answer string | choices dict | id string | kind string | lang string | question string | steps list | subject string | text string | topic string |
|---|---|---|---|---|---|---|---|---|---|
Empowerment gives employees authority to decide within bounds, speeding service and raising ownership. | null | bus_0201 | concept | en | What is employee empowerment? | [
"Define delegated decision authority.",
"Note faster frontline response.",
"Note higher ownership and morale."
] | business | Answer: Authority for employees to decide within bounds.
Steps:
1. Define delegated decision authority.
2. Note faster frontline response.
3. Note higher ownership and morale. | management |
Kaizen znamená neustálé drobné zlepšování procesů zdola, které se sčítá ve velké přínosy. | {
"A": "Jednorázová revoluce",
"B": "Neustálé drobné zlepšování",
"C": "Snižování mezd",
"D": "Rušením oddělení"
} | bus_0202 | multiple_choice | cs | Co znamená kaizen v managementu? | [
"Definuj postupné zlepšování.",
"Zapojení všech zaměstnanců.",
"Vyber možnost B."
] | business | Answer: Neustálé drobné zlepšování.
Steps:
1. Definuj postupné zlepšování.
2. Zapojení všech zaměstnanců.
3. Vyber možnost B.
Answer: (B) | management |
The span ratio is 1:8, from 24 workers divided by 3 team leaders. | null | bus_0203 | worked_example | en | A factory has 24 workers and 3 team leaders. Compute the supervisor span ratio. | [
"Write: Span = Workers / Leaders.",
"Substitute: 24 / 3 = 8.",
"Span ratio = 1:8."
] | business | Answer: 1:8.
Steps:
1. Write: Span = Workers / Leaders.
2. Substitute: 24 / 3 = 8.
3. Span ratio = 1:8. | management |
Benchmarking compares processes against best-in-class performers to find improvement gaps. | null | bus_0204 | concept | en | What is benchmarking? | [
"Define comparison to best practice.",
"Measure performance gaps.",
"Adopt better methods."
] | business | Answer: Comparing against best-in-class performers.
Steps:
1. Define comparison to best practice.
2. Measure performance gaps.
3. Adopt better methods. | management |
A laissez-faire leader grants full autonomy, which suits experts but risks drift without direction. | {
"A": "Controls every detail",
"B": "Grants full autonomy",
"C": "Decides by lottery",
"D": "Bans all initiative"
} | bus_0205 | multiple_choice | en | What is a laissez-faire leadership style? | [
"Recall hands-off autonomy.",
"Match to experts needing freedom.",
"Select option B."
] | business | Answer: Grants full autonomy.
Steps:
1. Recall hands-off autonomy.
2. Match to experts needing freedom.
3. Select option B.
Answer: (B) | management |
Engagement is 72%, from 180 engaged employees divided by 250 surveyed. | null | bus_0206 | worked_example | en | A survey finds 180 engaged employees out of 250. Compute the engagement rate. | [
"Write: Rate = Engaged / Surveyed.",
"Substitute: 180 / 250 = 0.72.",
"Engagement = 72%."
] | business | Answer: 72%.
Steps:
1. Write: Rate = Engaged / Surveyed.
2. Substitute: 180 / 250 = 0.72.
3. Engagement = 72%. | management |
Time management prioritizes tasks by impact and deadline so limited hours go to what matters most. | null | bus_0207 | concept | en | What is time management? | [
"Define prioritizing by impact.",
"Use deadlines to order work.",
"Protect focus from low-value tasks."
] | business | Answer: Prioritizing tasks by impact and deadline.
Steps:
1. Define prioritizing by impact.
2. Use deadlines to order work.
3. Protect focus from low-value tasks. | management |
Situační vedení přizpůsobuje styl zralosti týmu, od direktivy po delegování. | {
"A": "Vždy stejný styl",
"B": "Styl podle zralosti týmu",
"C": "Žádné vedení",
"D": "Jen tresty"
} | bus_0208 | multiple_choice | cs | Co je situační vedení? | [
"Posuď zralost a úkol.",
"Zvol direktivu nebo podporu.",
"Vyber možnost B."
] | business | Answer: Styl podle zralosti týmu.
Steps:
1. Posuď zralost a úkol.
2. Zvol direktivu nebo podporu.
3. Vyber možnost B.
Answer: (B) | management |
The retention rate is 88%, from 220 stayers divided by 250 employees at year start. | null | bus_0209 | worked_example | en | A firm starts the year with 250 employees and 220 stay. Compute the retention rate. | [
"Write: Retention = Stayers / Start.",
"Substitute: 220 / 250 = 0.88.",
"Retention = 88%."
] | business | Answer: 88%.
Steps:
1. Write: Retention = Stayers / Start.
2. Substitute: 220 / 250 = 0.88.
3. Retention = 88%. | management |
PEST analysis scans political, economic, social, and technological forces shaping the macro environment. | null | bus_0210 | concept | en | What does a PEST analysis cover? | [
"Name political and economic forces.",
"Name social and technological forces.",
"Use the scan for strategy input."
] | business | Answer: Political, economic, social, technological forces.
Steps:
1. Name political and economic forces.
2. Name social and technological forces.
3. Use the scan for strategy input. | firm_strategy |
A cash cow has high share in a slow market, funding other units with its surplus. | {
"A": "High share, high growth",
"B": "High share, low growth",
"C": "Low share, high growth",
"D": "Low share, low growth"
} | bus_0211 | multiple_choice | en | What is a cash cow in the BCG matrix? | [
"Recall BCG axes: share and growth.",
"Cash cow means high share, low growth.",
"Select option B."
] | business | Answer: High share, low growth.
Steps:
1. Recall BCG axes: share and growth.
2. Cash cow means high share, low growth.
3. Select option B.
Answer: (B) | firm_strategy |
Růst trhu je 20 %, protože (120 - 100) děleno 100 se rovná 0,20. | null | bus_0212 | worked_example | cs | Trh vzrostl ze 100 na 120 miliard Kč. Vypočítej tempo růstu trhu. | [
"Rozdíl = 120 - 100 = 20.",
"Vyděl základem: 20 / 100.",
"Růst = 20 %."
] | business | Answer: 20 %.
Steps:
1. Rozdíl = 120 - 100 = 20.
2. Vyděl základem: 20 / 100.
3. Růst = 20 %. | firm_strategy |
Market penetration grows by selling more of current products to current markets. | null | bus_0213 | concept | en | What is market penetration in the Ansoff matrix? | [
"Recall Ansoff axes: products and markets.",
"Penetration means current-current.",
"List tactics: pricing, promotion."
] | business | Answer: More of current products to current markets.
Steps:
1. Recall Ansoff axes: products and markets.
2. Penetration means current-current.
3. List tactics: pricing, promotion. | firm_strategy |
Diversification in Ansoff terms means new products for new markets, the riskiest growth path. | {
"A": "Current products, current markets",
"B": "New products, new markets",
"C": "Current products, new markets",
"D": "New products, current markets"
} | bus_0214 | multiple_choice | en | What is diversification in the Ansoff matrix? | [
"Recall both axes turn new.",
"Note highest risk.",
"Select option B."
] | business | Answer: New products, new markets.
Steps:
1. Recall both axes turn new.
2. Note highest risk.
3. Select option B.
Answer: (B) | firm_strategy |
The new-product share is 25%, from $50M new-product sales divided by $200M total sales. | null | bus_0215 | worked_example | en | New products generate $50M of $200M total sales. Compute the new-product sales share. | [
"Write: Share = New / Total.",
"Substitute: 50 / 200 = 0.25.",
"Share = 25%."
] | business | Answer: 25%.
Steps:
1. Write: Share = New / Total.
2. Substitute: 50 / 200 = 0.25.
3. Share = 25%. | firm_strategy |
Nákladové vedení vyžaduje úspory z rozsahu, štíhlé procesy a tvrdé vyjednávání s dodavateli. | null | bus_0216 | concept | cs | Jak firma dosáhne nákladového vedení? | [
"Využij úspory z rozsahu.",
"Zjednoduš procesy.",
"Vyjednej nízké ceny vstupů."
] | business | Answer: Rozsahem, štíhlostí a vyjednáváním.
Steps:
1. Využij úspory z rozsahu.
2. Zjednoduš procesy.
3. Vyjednej nízké ceny vstupů. | firm_strategy |
A question mark has low share in a fast market, needing investment to become a star or be dropped. | {
"A": "High share, low growth",
"B": "Low share, high growth",
"C": "High share, high growth",
"D": "Low share, low growth"
} | bus_0217 | multiple_choice | en | What is a question mark in the BCG matrix? | [
"Recall BCG axes.",
"Question mark means low share, high growth.",
"Select option B."
] | business | Answer: Low share, high growth.
Steps:
1. Recall BCG axes.
2. Question mark means low share, high growth.
3. Select option B.
Answer: (B) | firm_strategy |
The acquisition premium is 25%, from a $150M price minus $120M standalone value divided by $120M. | null | bus_0218 | worked_example | en | A buyer pays $150M for a firm worth $120M standalone. Compute the acquisition premium. | [
"Excess = 150 - 120 = 30.",
"Divide: 30 / 120 = 0.25.",
"Premium = 25%."
] | business | Answer: 25%.
Steps:
1. Excess = 150 - 120 = 30.
2. Divide: 30 / 120 = 0.25.
3. Premium = 25%. | firm_strategy |
Switching costs lock customers in by making change expensive in money, time, or learning. | null | bus_0219 | concept | en | What are switching costs? | [
"Define costs of changing supplier.",
"List money, time, learning.",
"Note they protect incumbents."
] | business | Answer: Costs that lock customers to a supplier.
Steps:
1. Define costs of changing supplier.
2. List money, time, learning.
3. Note they protect incumbents. | firm_strategy |
Síťový efekt zvyšuje hodnotu produktu s každým dalším uživatelem, což urychluje růst lídra. | {
"A": "Hodnota klesá s uživateli",
"B": "Hodnota roste s uživateli",
"C": "Uživatelé jsou irelevantní",
"D": "Platí jen pro hardware"
} | bus_0220 | multiple_choice | cs | Co je síťový efekt? | [
"Každý uživatel přidá hodnotu ostatním.",
"Růst se zrychluje.",
"Vyber možnost B."
] | business | Answer: Hodnota roste s uživateli.
Steps:
1. Každý uživatel přidá hodnotu ostatním.
2. Růst se zrychluje.
3. Vyber možnost B.
Answer: (B) | firm_strategy |
The divested share is 10%, from $20M divested sales divided by $200M total sales. | null | bus_0221 | worked_example | en | A firm divests a $20M unit from $200M total sales. Compute the divested sales share. | [
"Write: Share = Divested / Total.",
"Substitute: 20 / 200 = 0.10.",
"Share = 10%."
] | business | Answer: 10%.
Steps:
1. Write: Share = Divested / Total.
2. Substitute: 20 / 200 = 0.10.
3. Share = 10%. | firm_strategy |
A turnaround strategy cuts costs, refocuses the core, and rebuilds cash to rescue a declining firm. | null | bus_0222 | concept | en | What is a turnaround strategy? | [
"Stabilize cash first.",
"Cut costs and refocus.",
"Rebuild growth on the core."
] | business | Answer: Rescue plan built on cash, cuts, and refocus.
Steps:
1. Stabilize cash first.
2. Cut costs and refocus.
3. Rebuild growth on the core. | firm_strategy |
Horizontal mergers unite rivals at the same stage, raising share but inviting antitrust review. | {
"A": "Unite suppliers and buyers",
"B": "Unite direct rivals",
"C": "Split one firm in two",
"D": "Sell to customers"
} | bus_0223 | multiple_choice | en | What is a horizontal merger? | [
"Recall same-stage combination.",
"Note share gains and scrutiny.",
"Select option B."
] | business | Answer: Unite direct rivals.
Steps:
1. Recall same-stage combination.
2. Note share gains and scrutiny.
3. Select option B.
Answer: (B) | firm_strategy |
Koncentrace dvou největších firem je 55 %, protože 35 % plus 20 % se rovná 55 %. | null | bus_0224 | worked_example | cs | Dvě největší firmy mají podíly 35 % a 20 %. Vypočítej jejich společnou koncentraci. | [
"Sečti podíly: 35 + 20.",
"Výsledek = 55 %.",
"Vysoká koncentrace znamená oligopol."
] | business | Answer: 55 %.
Steps:
1. Sečti podíly: 35 + 20.
2. Výsledek = 55 %.
3. Vysoká koncentrace znamená oligopol. | firm_strategy |
Strategic fit means activities reinforce each other, making the whole strategy hard to imitate. | null | bus_0225 | concept | en | What is strategic fit? | [
"Define mutually reinforcing activities.",
"Explain system-level advantage.",
"Note imitation difficulty."
] | business | Answer: Activities that reinforce each other.
Steps:
1. Define mutually reinforcing activities.
2. Explain system-level advantage.
3. Note imitation difficulty. | firm_strategy |
A dog has low share in a slow market and is usually divested or harvested. | {
"A": "High share, high growth",
"B": "Low share, low growth",
"C": "High share, low growth",
"D": "Low share, high growth"
} | bus_0226 | multiple_choice | en | What is a dog in the BCG matrix? | [
"Recall BCG axes.",
"Dog means low share, low growth.",
"Select option B."
] | business | Answer: Low share, low growth.
Steps:
1. Recall BCG axes.
2. Dog means low share, low growth.
3. Select option B.
Answer: (B) | firm_strategy |
Licensing grants foreign partners rights to technology or brand for royalties, a low-risk entry mode. | null | bus_0227 | concept | en | What is licensing as a market entry mode? | [
"Define rights granted for royalties.",
"Note low investment and risk.",
"Note limited control."
] | business | Answer: Rights granted abroad for royalties.
Steps:
1. Define rights granted for royalties.
2. Note low investment and risk.
3. Note limited control. | firm_strategy |
Licenční poplatek je 500 000 Kč, protože 5 % z 10 milionů Kč se rovná 500 000 Kč. | null | bus_0228 | worked_example | cs | Licence činí 5 % z tržeb 10 milionů Kč. Vypočítej licenční poplatek. | [
"Napiš vzorec: tržby x sazba.",
"Dosaď: 10 000 000 x 0,05.",
"Poplatek = 500 000 Kč."
] | business | Answer: 500 000 Kč.
Steps:
1. Napiš vzorec: tržby x sazba.
2. Dosaď: 10 000 000 x 0,05.
3. Poplatek = 500 000 Kč. | firm_strategy |
A star has high share in a fast market and needs investment to defend its lead. | null | bus_0229 | concept | en | What is a star in the BCG matrix? | [
"Recall BCG axes.",
"Star means high share, high growth.",
"Note investment need."
] | business | Answer: High share in a fast-growing market.
Steps:
1. Recall BCG axes.
2. Star means high share, high growth.
3. Note investment need. | firm_strategy |
Profit margin is 12%, from $60,000 profit divided by $500,000 sales. | null | bus_0230 | worked_example | en | Profit is $60,000 on sales of $500,000. Compute the profit margin. | [
"Write: Margin = Profit / Sales.",
"Substitute: 60,000 / 500,000 = 0.12.",
"Margin = 12%."
] | business | Answer: 12%.
Steps:
1. Write: Margin = Profit / Sales.
2. Substitute: 60,000 / 500,000 = 0.12.
3. Margin = 12%. | business_math |
Opportunity cost is the value of the best alternative given up when a choice is made. | {
"A": "Total accounting cost",
"B": "Value of the best alternative given up",
"C": "Sunk cost only",
"D": "Fixed cost only"
} | bus_0231 | multiple_choice | en | What is opportunity cost? | [
"Recall forgone-alternative definition.",
"Eliminate accounting, sunk, fixed.",
"Select option B."
] | business | Answer: Value of the best alternative given up.
Steps:
1. Recall forgone-alternative definition.
2. Eliminate accounting, sunk, fixed.
3. Select option B.
Answer: (B) | business_math |
The annuity value is $3,310, from $1,000 times (1.05^3 - 1) / 0.05 = 1,000 x 3.310. | null | bus_0232 | worked_example | en | Compute the future value of $1,000 saved yearly for 3 years at 5% interest. | [
"Factor = (1.05^3 - 1) / 0.05 = 3.310.",
"Multiply: 1,000 x 3.310.",
"FV = $3,310."
] | business | Answer: $3,310.
Steps:
1. Factor = (1.05^3 - 1) / 0.05 = 3.310.
2. Multiply: 1,000 x 3.310.
3. FV = $3,310. | business_math |
Anuita je série stejných plateb v pravidelných intervalech, například měsíční splátky úvěru. | null | bus_0233 | concept | cs | Co je anuita? | [
"Definuj stejné pravidelné platby.",
"Uveď příklad splátek úvěru.",
"Rozliš předlhůtní a polhůtní."
] | business | Answer: Stejné platby v pravidelných intervalech.
Steps:
1. Definuj stejné pravidelné platby.
2. Uveď příklad splátek úvěru.
3. Rozliš předlhůtní a polhůtní. | business_math |
Total interest of $450 comes from $5,000 at 3% annual simple interest for 3 years. | {
"A": "$150",
"B": "$300",
"C": "$450",
"D": "$500"
} | bus_0234 | multiple_choice | en | What is the simple interest on $5,000 at 3% for 3 years? | [
"Write: I = 5,000 x 0.03 x 3.",
"Compute: 5,000 x 0.09 = 450.",
"Select option C."
] | business | Answer: $450.
Steps:
1. Write: I = 5,000 x 0.03 x 3.
2. Compute: 5,000 x 0.09 = 450.
3. Select option C.
Answer: (C) | business_math |
Cena s DPH je 12 100 Kč, protože 10 000 krát 1,21 je 12 100. | null | bus_0235 | worked_example | cs | Cena bez DPH je 10 000 Kč a sazba DPH 21 %. Vypočítej cenu s DPH. | [
"Napiš vzorec: 10 000 x 1,21.",
"Vynásob: 10 000 x 1,21.",
"Cena s DPH = 12 100 Kč."
] | business | Answer: 12 100 Kč.
Steps:
1. Napiš vzorec: 10 000 x 1,21.
2. Vynásob: 10 000 x 1,21.
3. Cena s DPH = 12 100 Kč. | business_math |
Marginal cost is the cost of producing one more unit and guides produce-or-stop decisions. | null | bus_0236 | concept | en | What is marginal cost? | [
"Define cost of one extra unit.",
"Compare to marginal revenue.",
"Produce while MR exceeds MC."
] | business | Answer: Cost of one more unit.
Steps:
1. Define cost of one extra unit.
2. Compare to marginal revenue.
3. Produce while MR exceeds MC. | business_math |
The exchange yields 22,500 CZK, from 1,000 EUR times 22.50. | {
"A": "20,000 CZK",
"B": "21,500 CZK",
"C": "22,500 CZK",
"D": "25,000 CZK"
} | bus_0237 | multiple_choice | en | Convert 1,000 EUR to CZK at 22.50 CZK per EUR. | [
"Write: 1,000 x 22.50.",
"Compute: 22,500.",
"Select option C."
] | business | Answer: 22,500 CZK.
Steps:
1. Write: 1,000 x 22.50.
2. Compute: 22,500.
3. Select option C.
Answer: (C) | business_math |
Jednotkové náklady jsou 250 Kč, protože 500 000 děleno 2 000 se rovná 250. | null | bus_0238 | worked_example | cs | Celkové náklady jsou 500 000 Kč na 2 000 kusů. Vypočítej jednotkové náklady. | [
"Napiš vzorec: celkem / kusy.",
"Dosaď: 500 000 / 2 000.",
"Náklady = 250 Kč na kus."
] | business | Answer: 250 Kč.
Steps:
1. Napiš vzorec: celkem / kusy.
2. Dosaď: 500 000 / 2 000.
3. Náklady = 250 Kč na kus. | business_math |
Sunk costs are past and unrecoverable, so rational decisions ignore them. | null | bus_0239 | concept | en | Why should sunk costs be ignored in decisions? | [
"Define sunk as past and unrecoverable.",
"Note no choice changes them.",
"Decide on future costs and benefits."
] | business | Answer: They are unrecoverable and unaffected by choice.
Steps:
1. Define sunk as past and unrecoverable.
2. Note no choice changes them.
3. Decide on future costs and benefits. | business_math |
The wage bill rises by $24,000, from 20 workers times a $100 monthly raise times 12 months. | {
"A": "$12,000",
"B": "$20,000",
"C": "$24,000",
"D": "$30,000"
} | bus_0240 | multiple_choice | en | Twenty workers get a $100 monthly raise. What is the yearly cost increase? | [
"Monthly rise = 20 x 100 = 2,000.",
"Yearly = 2,000 x 12 = 24,000.",
"Select option C."
] | business | Answer: $24,000.
Steps:
1. Monthly rise = 20 x 100 = 2,000.
2. Yearly = 2,000 x 12 = 24,000.
3. Select option C.
Answer: (C) | business_math |
Days sales outstanding is 36.5 days, from 365 divided by a receivables turnover of 10. | null | bus_0241 | worked_example | en | Receivables turnover is 10 times per year. Compute days sales outstanding. | [
"Write: DSO = 365 / Turnover.",
"Substitute: 365 / 10.",
"DSO = 36.5 days."
] | business | Answer: 36.5 days.
Steps:
1. Write: DSO = 365 / Turnover.
2. Substitute: 365 / 10.
3. DSO = 36.5 days. | business_math |
Rozdíl mezi hrubou a čistou mzdou tvoří daň z příjmu a odvody na pojištění. | null | bus_0242 | concept | cs | Co tvoří rozdíl mezi hrubou a čistou mzdou? | [
"Hrubá mzda je sjednaná částka.",
"Odečti daň a pojistné.",
"Zbytek je čistá mzda."
] | business | Answer: Daň z příjmu a pojistné odvody.
Steps:
1. Hrubá mzda je sjednaná částka.
2. Odečti daň a pojistné.
3. Zbytek je čistá mzda. | business_math |
The real rate is about 2.9%, from (1.05 / 1.02) minus 1. | {
"A": "2.0%",
"B": "2.9%",
"C": "3.0%",
"D": "7.0%"
} | bus_0243 | multiple_choice | en | The nominal rate is 5% and inflation is 2%. What is the real interest rate? | [
"Write: (1.05 / 1.02) - 1.",
"Compute: 1.0294 - 1 = 0.0294.",
"Select option B."
] | business | Answer: About 2.9%.
Steps:
1. Write: (1.05 / 1.02) - 1.
2. Compute: 1.0294 - 1 = 0.0294.
3. Select option B.
Answer: (B) | business_math |
The EOQ is 447 units, from the square root of (2 x 10,000 x 100) / 10. | null | bus_0244 | worked_example | en | Annual demand is 10,000 units, ordering cost is $100, and holding cost is $10 per unit. Compute EOQ. | [
"Write: sqrt(2 x 10,000 x 100 / 10).",
"Simplify: sqrt(200,000).",
"EOQ = 447 units."
] | business | Answer: 447 units.
Steps:
1. Write: sqrt(2 x 10,000 x 100 / 10).
2. Simplify: sqrt(200,000).
3. EOQ = 447 units. | business_math |
Amortization spreads a loan into equal payments covering interest first and principal increasingly over time. | null | bus_0245 | concept | en | How does loan amortization work? | [
"Fix equal periodic payments.",
"Early payments skew to interest.",
"Later payments skew to principal."
] | business | Answer: Equal payments shifting from interest to principal.
Steps:
1. Fix equal periodic payments.
2. Early payments skew to interest.
3. Later payments skew to principal. | business_math |
Provize 7 % z 2 milionů Kč činí 140 000 Kč. | {
"A": "100 000 Kč",
"B": "120 000 Kč",
"C": "140 000 Kč",
"D": "200 000 Kč"
} | bus_0246 | multiple_choice | cs | Obchodník má provizi 7 % z prodeje 2 miliony Kč. Kolik činí provize? | [
"Napiš vzorec: 2 000 000 x 0,07.",
"Vypočítej: 140 000.",
"Vyber možnost C."
] | business | Answer: 140 000 Kč.
Steps:
1. Napiš vzorec: 2 000 000 x 0,07.
2. Vypočítej: 140 000.
3. Vyber možnost C.
Answer: (C) | business_math |
The contribution margin ratio is 40%, from ($50 - $30) divided by $50. | null | bus_0247 | worked_example | en | Price is $50 and variable cost is $30. Compute the contribution margin ratio. | [
"Margin = 50 - 30 = 20.",
"Divide: 20 / 50 = 0.40.",
"Ratio = 40%."
] | business | Answer: 40%.
Steps:
1. Margin = 50 - 30 = 20.
2. Divide: 20 / 50 = 0.40.
3. Ratio = 40%. | business_math |
Index numbers track relative change against a base period set to 100. | null | bus_0248 | concept | en | What is an index number? | [
"Set a base period to 100.",
"Express later values relatively.",
"Read 110 as 10% growth."
] | business | Answer: Relative change against base 100.
Steps:
1. Set a base period to 100.
2. Express later values relatively.
3. Read 110 as 10% growth. | business_math |
The weighted average is 83, from 45 plus 24 plus 14. | {
"A": "78",
"B": "80",
"C": "83",
"D": "85"
} | bus_0249 | multiple_choice | en | Scores of 90, 80, and 70 carry weights 0.5, 0.3, and 0.2. Compute the weighted average. | [
"Multiply: 0.5x90=45, 0.3x80=24, 0.2x70=14.",
"Sum: 45 + 24 + 14 = 83.",
"Select option C."
] | business | Answer: 83.
Steps:
1. Multiply: 0.5x90=45, 0.3x80=24, 0.2x70=14.
2. Sum: 45 + 24 + 14 = 83.
3. Select option C.
Answer: (C) | business_math |
Cena po slevě je 1 700 Kč, protože 2 000 minus 15 % (300) se rovná 1 700. | null | bus_0250 | worked_example | cs | Zboží za 2 000 Kč je zlevněno o 15 %. Vypočítej cenu po slevě. | [
"Sleva = 2 000 x 0,15 = 300.",
"Odečti: 2 000 - 300.",
"Cena = 1 700 Kč."
] | business | Answer: 1 700 Kč.
Steps:
1. Sleva = 2 000 x 0,15 = 300.
2. Odečti: 2 000 - 300.
3. Cena = 1 700 Kč. | business_math |
One mole contains exactly 6.022 x 10^23 particles, linking atomic-scale mass to grams chemists can weigh. | null | che_0001 | concept | en | What is a mole in chemistry? | [
"Define the mole as the SI amount unit.",
"Give Avogadro's number: 6.022 x 10^23 per mole.",
"Note molar mass converts moles to grams."
] | chemistry | Answer: 6.022 x 10^23 particles.
Steps:
1. Define the mole as the SI amount unit.
2. Give Avogadro's number: 6.022 x 10^23 per mole.
3. Note molar mass converts moles to grams. | stoichiometry |
There are 2.00 mol of water, from 36.0 g divided by 18.015 g/mol. | null | che_0002 | worked_example | en | How many moles are in 36.0 g of water (M = 18.015 g/mol)? | [
"Write: n = mass / molar mass.",
"Substitute: 36.0 / 18.015.",
"n = 2.00 mol."
] | chemistry | Answer: 2.00 mol.
Steps:
1. Write: n = mass / molar mass.
2. Substitute: 36.0 / 18.015.
3. n = 2.00 mol. | stoichiometry |
The molar mass of CO2 is 44.01 g/mol, from 12.01 plus twice 16.00. | {
"A": "28.01 g/mol",
"B": "32.00 g/mol",
"C": "44.01 g/mol",
"D": "18.02 g/mol"
} | che_0003 | multiple_choice | en | What is the molar mass of carbon dioxide? | [
"Add C: 12.01.",
"Add two O: 2 x 16.00 = 32.00.",
"Total 44.01; select C."
] | chemistry | Answer: 44.01 g/mol.
Steps:
1. Add C: 12.01.
2. Add two O: 2 x 16.00 = 32.00.
3. Total 44.01; select C.
Answer: (C) | stoichiometry |
Mol je jednotka látkového množství obsahující 6,022 x 10^23 částic, což spojuje atomové hmotnosti s gramy. | null | che_0004 | concept | cs | Co je mol (látkové množství)? | [
"Definuj mol jako jednotku SI.",
"Uveď Avogadrovu konstantu 6,022 x 10^23.",
"Vysvětli převod přes molární hmotnost."
] | chemistry | Answer: 6,022 x 10^23 částic.
Steps:
1. Definuj mol jako jednotku SI.
2. Uveď Avogadrovu konstantu 6,022 x 10^23.
3. Vysvětli převod přes molární hmotnost. | stoichiometry |
The mass is 146.1 g, from 2.50 mol times 58.44 g/mol. | null | che_0005 | worked_example | en | What mass is 2.50 mol of NaCl (M = 58.44 g/mol)? | [
"Write: mass = n x M.",
"Substitute: 2.50 x 58.44.",
"Mass = 146.1 g."
] | chemistry | Answer: 146.1 g.
Steps:
1. Write: mass = n x M.
2. Substitute: 2.50 x 58.44.
3. Mass = 146.1 g. | stoichiometry |
Oxygen is limiting because 1 mol O2 needs 2 mol H2 but 4 mol H2 are present, so at most 2 mol H2O form. | {
"A": "H2 is limiting",
"B": "O2 is limiting",
"C": "Both limit equally",
"D": "Neither limits"
} | che_0006 | multiple_choice | en | For 2H2 + O2 -> 2H2O with 4 mol H2 and 1 mol O2, which reactant limits? | [
"Need ratio H2:O2 = 2:1.",
"Have ratio 4:1, excess H2.",
"Select option B."
] | chemistry | Answer: O2 is limiting.
Steps:
1. Need ratio H2:O2 = 2:1.
2. Have ratio 4:1, excess H2.
3. Select option B.
Answer: (B) | stoichiometry |
Balancing enforces conservation of mass so each element has equal atom counts on both sides of the equation. | null | che_0007 | concept | en | Why must chemical equations be balanced? | [
"State conservation of mass.",
"Require equal atoms per element both sides.",
"Adjust coefficients, never subscripts."
] | chemistry | Answer: To conserve atoms of each element.
Steps:
1. State conservation of mass.
2. Require equal atoms per element both sides.
3. Adjust coefficients, never subscripts. | stoichiometry |
Ve 44 g CO2 je 1,00 mol, protože 44 děleno 44,01 se rovná 1,00. | null | che_0008 | worked_example | cs | Kolik molů je ve 44 g CO2 (M = 44,01 g/mol)? | [
"Napiš vzorec: n = m / M.",
"Dosaď: 44 / 44,01.",
"n = 1,00 mol."
] | chemistry | Answer: 1,00 mol.
Steps:
1. Napiš vzorec: n = m / M.
2. Dosaď: 44 / 44,01.
3. n = 1,00 mol. | stoichiometry |
Percent yield is 80%, from 40 g actual divided by 50 g theoretical times 100. | {
"A": "60%",
"B": "70%",
"C": "80%",
"D": "90%"
} | che_0009 | multiple_choice | en | Theoretical yield is 50 g and actual yield is 40 g. What is the percent yield? | [
"Write: actual / theoretical x 100.",
"Substitute: 40 / 50 x 100 = 80.",
"Select option C."
] | chemistry | Answer: 80%.
Steps:
1. Write: actual / theoretical x 100.
2. Substitute: 40 / 50 x 100 = 80.
3. Select option C.
Answer: (C) | stoichiometry |
The empirical formula gives the simplest whole-number atom ratio while the molecular formula gives the true atom counts. | null | che_0010 | concept | en | How do empirical and molecular formulas differ? | [
"Define empirical as simplest ratio.",
"Define molecular as actual counts.",
"Give glucose: CH2O versus C6H12O6."
] | chemistry | Answer: Simplest ratio versus true counts.
Steps:
1. Define empirical as simplest ratio.
2. Define molecular as actual counts.
3. Give glucose: CH2O versus C6H12O6. | stoichiometry |
There are 3.011 x 10^23 atoms, from 0.500 mol times 6.022 x 10^23 per mole. | null | che_0011 | worked_example | en | How many atoms are in 0.500 mol of iron? | [
"Write: N = n x Avogadro.",
"Substitute: 0.500 x 6.022 x 10^23.",
"N = 3.011 x 10^23 atoms."
] | chemistry | Answer: 3.011 x 10^23 atoms.
Steps:
1. Write: N = n x Avogadro.
2. Substitute: 0.500 x 6.022 x 10^23.
3. N = 3.011 x 10^23 atoms. | stoichiometry |
Molární hmotnost je hmotnost jednoho molu látky v g/mol, číselně rovná relativní molekulové hmotnosti. | null | che_0012 | concept | cs | Co je molární hmotnost? | [
"Definuj hmotnost 1 molu.",
"Jednotka g/mol.",
"Příklad: voda 18,015 g/mol."
] | chemistry | Answer: Hmotnost 1 molu v g/mol.
Steps:
1. Definuj hmotnost 1 molu.
2. Jednotka g/mol.
3. Příklad: voda 18,015 g/mol. | stoichiometry |
The balanced equation is CH4 + 2O2 -> CO2 + 2H2O, with coefficients 1, 2, 1, 2. | {
"A": "1, 1, 1, 1",
"B": "1, 2, 2, 1",
"C": "2, 2, 1, 2",
"D": "1, 2, 1, 2"
} | che_0013 | multiple_choice | en | What coefficients balance CH4 + O2 -> CO2 + H2O? | [
"Balance C: 1 each side.",
"Balance H with 2 H2O.",
"Balance O with 2 O2; select D."
] | chemistry | Answer: 1, 2, 1, 2.
Steps:
1. Balance C: 1 each side.
2. Balance H with 2 H2O.
3. Balance O with 2 O2; select D.
Answer: (D) | stoichiometry |
The volume is 44.8 L, from 2.00 mol times 22.414 L/mol at STP. | null | che_0014 | worked_example | en | What volume does 2.00 mol of ideal gas occupy at STP (22.414 L/mol)? | [
"Write: V = n x molar volume.",
"Substitute: 2.00 x 22.414.",
"V = 44.8 L."
] | chemistry | Answer: 44.8 L.
Steps:
1. Write: V = n x molar volume.
2. Substitute: 2.00 x 22.414.
3. V = 44.8 L. | stoichiometry |
Limitující reaktant se spotřebuje jako první a určuje maximální množství produktu. | null | che_0015 | concept | cs | Co je limitující reaktant? | [
"Definuj reaktant spotřebovaný první.",
"Určuje maximální výtěžek.",
"Ostatní jsou v nadbytku."
] | chemistry | Answer: Reaktant určující maximální výtěžek.
Steps:
1. Definuj reaktant spotřebovaný první.
2. Určuje maximální výtěžek.
3. Ostatní jsou v nadbytku. | stoichiometry |
The concentration is 0.25 M, from 0.500 mol divided by 2.00 L. | {
"A": "0.25 M",
"B": "0.50 M",
"C": "1.00 M",
"D": "4.00 M"
} | che_0016 | multiple_choice | en | What is the molarity of 0.500 mol dissolved in 2.00 L? | [
"Write: M = n / V.",
"Substitute: 0.500 / 2.00 = 0.25.",
"Select option A."
] | chemistry | Answer: 0.25 M.
Steps:
1. Write: M = n / V.
2. Substitute: 0.500 / 2.00 = 0.25.
3. Select option A.
Answer: (A) | stoichiometry |
Dilute to 300 mL total by adding 200 mL water, since 100 mL x 6 M / 2 M = 300 mL. | null | che_0017 | worked_example | en | How to dilute 100 mL of 6.0 M stock to 2.0 M? | [
"Use M1V1 = M2V2.",
"V2 = 100 x 6.0 / 2.0 = 300 mL.",
"Add 300 - 100 = 200 mL water."
] | chemistry | Answer: Add 200 mL water to reach 300 mL.
Steps:
1. Use M1V1 = M2V2.
2. V2 = 100 x 6.0 / 2.0 = 300 mL.
3. Add 300 - 100 = 200 mL water. | stoichiometry |
Avogadro's law states equal gas volumes at equal temperature and pressure contain equal numbers of molecules. | null | che_0018 | concept | en | What is Avogadro's law? | [
"Fix temperature and pressure.",
"Volume scales with moles.",
"All ideal gases share molar volume."
] | chemistry | Answer: Equal volumes hold equal molecule counts.
Steps:
1. Fix temperature and pressure.
2. Volume scales with moles.
3. All ideal gases share molar volume. | stoichiometry |
Dva moly vody váží 36 g, protože 2 krát 18,015 se rovná 36,03. | {
"A": "9 g",
"B": "18 g",
"C": "36 g",
"D": "44 g"
} | che_0019 | multiple_choice | cs | Kolik gramů váží 2 moly vody? | [
"Vynásob: 2 x 18,015 = 36,03.",
"Zaokrouhli na 36 g.",
"Vyber možnost C."
] | chemistry | Answer: 36 g.
Steps:
1. Vynásob: 2 x 18,015 = 36,03.
2. Zaokrouhli na 36 g.
3. Vyber možnost C.
Answer: (C) | stoichiometry |
A Bronsted-Lowry acid donates a proton while a base accepts one, forming conjugate pairs. | null | che_0020 | concept | en | What is the Bronsted-Lowry definition of acids and bases? | [
"Define acid as proton donor.",
"Define base as proton acceptor.",
"Link pairs like HCl/Cl-."
] | chemistry | Answer: Acids donate, bases accept protons.
Steps:
1. Define acid as proton donor.
2. Define base as proton acceptor.
3. Link pairs like HCl/Cl-. | acids_bases |
The conjugate base of H2SO4 is HSO4-, formed by losing one proton. | {
"A": "SO4(2-)",
"B": "HSO4(-)",
"C": "H3SO4(+)",
"D": "OH(-)"
} | che_0021 | multiple_choice | en | What is the conjugate base of sulfuric acid (H2SO4)? | [
"Remove one H+ from H2SO4.",
"Result is HSO4-.",
"Select option B."
] | chemistry | Answer: HSO4-.
Steps:
1. Remove one H+ from H2SO4.
2. Result is HSO4-.
3. Select option B.
Answer: (B) | acids_bases |
The pH is 2.00, from -log(0.010) for the strong acid HCl. | null | che_0022 | worked_example | en | Compute the pH of 0.010 M HCl. | [
"HCl dissociates fully: [H+] = 0.010 M.",
"Write: pH = -log[H+].",
"pH = -log(0.010) = 2.00."
] | chemistry | Answer: 2.00.
Steps:
1. HCl dissociates fully: [H+] = 0.010 M.
2. Write: pH = -log[H+].
3. pH = -log(0.010) = 2.00. | acids_bases |
pH je záporný dekadický logaritmus koncentrace iontů H+, takže pH 7 je neutrální. | null | che_0023 | concept | cs | Co je pH a jak se počítá? | [
"Definuj pH = -log[H+].",
"Pod 7 kyselé, nad 7 zásadité.",
"Příklad: 0,01 M HCl má pH 2."
] | chemistry | Answer: Záporný logaritmus [H+].
Steps:
1. Definuj pH = -log[H+].
2. Pod 7 kyselé, nad 7 zásadité.
3. Příklad: 0,01 M HCl má pH 2. | acids_bases |
HCl is the strong acid because it dissociates fully, unlike the weak acids listed. | {
"A": "HCl",
"B": "CH3COOH",
"C": "H2CO3",
"D": "NH4(+)"
} | che_0024 | multiple_choice | en | Which of these is a strong acid? | [
"Recall strong acids dissociate fully.",
"Eliminate acetic, carbonic, ammonium.",
"Select option A."
] | chemistry | Answer: HCl.
Steps:
1. Recall strong acids dissociate fully.
2. Eliminate acetic, carbonic, ammonium.
3. Select option A.
Answer: (A) | acids_bases |
Neutralization combines H+ and OH- into water while the counterions form a salt. | null | che_0025 | concept | en | What happens in a neutralization reaction? | [
"Combine H+ with OH- to make water.",
"Pair remaining ions as salt.",
"Example: HCl + NaOH -> NaCl + H2O."
] | chemistry | Answer: Acid plus base give salt and water.
Steps:
1. Combine H+ with OH- to make water.
2. Pair remaining ions as salt.
3. Example: HCl + NaOH -> NaCl + H2O. | acids_bases |
At 25 C the sum pH + pOH equals 14, so each can be found from the other. | null | che_0026 | concept | en | How are pH and pOH related? | [
"Define pOH = -log[OH-].",
"Use Kw: pH + pOH = 14 at 25 C.",
"Convert: pH = 14 - pOH."
] | chemistry | Answer: pH + pOH = 14 at 25 C.
Steps:
1. Define pOH = -log[OH-].
2. Use Kw: pH + pOH = 14 at 25 C.
3. Convert: pH = 14 - pOH. | acids_bases |
The hydrogen ion concentration is 3.16 x 10^-4 M, from 10 raised to -3.50. | null | che_0027 | worked_example | en | A solution has pH 3.50. Compute [H+]. | [
"Write: [H+] = 10^(-pH).",
"Substitute: 10^(-3.50).",
"[H+] = 3.16 x 10^-4 M."
] | chemistry | Answer: 3.16 x 10^-4 M.
Steps:
1. Write: [H+] = 10^(-pH).
2. Substitute: 10^(-3.50).
3. [H+] = 3.16 x 10^-4 M. | acids_bases |
A buffer pairs a weak acid with its conjugate base to resist pH change. | {
"A": "Strong acid plus strong base",
"B": "Weak acid only",
"C": "Salt only",
"D": "Weak acid plus conjugate base"
} | che_0028 | multiple_choice | en | Which mixture forms a buffer? | [
"Recall buffers need conjugate pairs.",
"Eliminate strong-strong, single, salt-only.",
"Select option D."
] | chemistry | Answer: Weak acid plus conjugate base.
Steps:
1. Recall buffers need conjugate pairs.
2. Eliminate strong-strong, single, salt-only.
3. Select option D.
Answer: (D) | acids_bases |
pH je 11, protože pOH = -log(0,001) = 3 a pH = 14 - 3. | null | che_0029 | worked_example | cs | Vypočítej pH roztoku 0,001 M NaOH. | [
"NaOH disociuje plně: [OH-] = 0,001 M.",
"pOH = -log(0,001) = 3.",
"pH = 14 - 3 = 11."
] | chemistry | Answer: 11.
Steps:
1. NaOH disociuje plně: [OH-] = 0,001 M.
2. pOH = -log(0,001) = 3.
3. pH = 14 - 3 = 11. | acids_bases |
Exactly 25.0 mL of 0.100 M NaOH is needed, matching moles of HCl one to one. | null | che_0030 | worked_example | en | What volume of 0.100 M NaOH neutralizes 25.0 mL of 0.100 M HCl? | [
"Moles HCl = 0.0250 x 0.100 = 0.00250 mol.",
"Same moles NaOH needed (1:1).",
"V = 0.00250 / 0.100 = 0.0250 L = 25.0 mL."
] | chemistry | Answer: 25.0 mL.
Steps:
1. Moles HCl = 0.0250 x 0.100 = 0.00250 mol.
2. Same moles NaOH needed (1:1).
3. V = 0.00250 / 0.100 = 0.0250 L = 25.0 mL. | acids_bases |
A Lewis acid accepts an electron pair while a Lewis base donates one, generalizing beyond protons. | null | che_0031 | concept | en | What is the Lewis definition of acids and bases? | [
"Define Lewis acid as pair acceptor.",
"Define Lewis base as pair donor.",
"Example: BF3 with NH3."
] | chemistry | Answer: Acids accept, bases donate electron pairs.
Steps:
1. Define Lewis acid as pair acceptor.
2. Define Lewis base as pair donor.
3. Example: BF3 with NH3. | acids_bases |
For a conjugate pair Ka times Kb equals Kw, which is 1.0 x 10^-14 at 25 C. | {
"A": "Ka x Kb = Kw",
"B": "Ka + Kb = Kw",
"C": "Ka / Kb = Kw",
"D": "Ka - Kb = Kw"
} | che_0032 | multiple_choice | en | How are Ka and Kb of a conjugate pair related? | [
"Recall product equals water constant.",
"Kw = 1.0 x 10^-14 at 25 C.",
"Select option A."
] | chemistry | Answer: Ka x Kb = Kw.
Steps:
1. Recall product equals water constant.
2. Kw = 1.0 x 10^-14 at 25 C.
3. Select option A.
Answer: (A) | acids_bases |
Neutralizace je reakce kyseliny se zásadou za vzniku soli a vody. | null | che_0033 | concept | cs | Co je neutralizace? | [
"Kyselina dodá H+, zásada OH-.",
"Vznikne voda a sůl.",
"Příklad: HCl + NaOH -> NaCl + H2O."
] | chemistry | Answer: Kyselina + zásada -> sůl + voda.
Steps:
1. Kyselina dodá H+, zásada OH-.
2. Vznikne voda a sůl.
3. Příklad: HCl + NaOH -> NaCl + H2O. | acids_bases |
The equivalence point is reached when added titrant stoichiometrically matches the analyte. | null | che_0034 | concept | en | What is the equivalence point of a titration? | [
"Define stoichiometric match.",
"Contrast with indicator endpoint.",
"Moles titrant = moles analyte x ratio."
] | chemistry | Answer: Stoichiometric match of titrant and analyte.
Steps:
1. Define stoichiometric match.
2. Contrast with indicator endpoint.
3. Moles titrant = moles analyte x ratio. | acids_bases |
Phosphoric acid is triprotic with three dissociable protons and three Ka values. | {
"A": "Monoprotic",
"B": "Diprotic",
"C": "Triprotic",
"D": "Aprotic"
} | che_0035 | multiple_choice | en | How is phosphoric acid (H3PO4) classified? | [
"Count dissociable protons: three.",
"Match to triprotic.",
"Select option C."
] | chemistry | Answer: Triprotic.
Steps:
1. Count dissociable protons: three.
2. Match to triprotic.
3. Select option C.
Answer: (C) | acids_bases |
Koncentrace H+ je 1 x 10^-5 M, protože 10 na -5 odpovídá pH 5. | null | che_0036 | worked_example | cs | Roztok má pH 5. Vypočítej [H+]. | [
"Napiš vzorec: [H+] = 10^(-pH).",
"Dosaď: 10^(-5).",
"[H+] = 1 x 10^-5 M."
] | chemistry | Answer: 1 x 10^-5 M.
Steps:
1. Napiš vzorec: [H+] = 10^(-pH).
2. Dosaď: 10^(-5).
3. [H+] = 1 x 10^-5 M. | acids_bases |
Phenolphthalein stays colorless in acid and turns pink in base around pH 8-10. | {
"A": "Pink in acid, colorless in base",
"B": "Blue in acid, yellow in base",
"C": "Colorless in acid, pink in base",
"D": "Red in acid, blue in base"
} | che_0037 | multiple_choice | en | How does phenolphthalein change color? | [
"Recall acid form is colorless.",
"Base form is pink above pH 8.",
"Select option C."
] | chemistry | Answer: Colorless in acid, pink in base.
Steps:
1. Recall acid form is colorless.
2. Base form is pink above pH 8.
3. Select option C.
Answer: (C) | acids_bases |
The pH is 2.87, from [H+] = sqrt(1.8 x 10^-5 x 0.10) = 1.34 x 10^-3 M. | null | che_0038 | worked_example | en | Compute the pH of 0.10 M acetic acid (Ka = 1.8 x 10^-5). | [
"Approximate: [H+] = sqrt(Ka x C).",
"Substitute: sqrt(1.8 x 10^-6) = 1.34 x 10^-3.",
"pH = -log(1.34 x 10^-3) = 2.87."
] | chemistry | Answer: 2.87.
Steps:
1. Approximate: [H+] = sqrt(Ka x C).
2. Substitute: sqrt(1.8 x 10^-6) = 1.34 x 10^-3.
3. pH = -log(1.34 x 10^-3) = 2.87. | acids_bases |
Oxidation is loss of electrons and reduction is gain, remembered as OILRIG. | null | che_0039 | concept | en | What are oxidation and reduction? | [
"Oxidation: lose electrons.",
"Reduction: gain electrons.",
"They always occur together."
] | chemistry | Answer: Loss versus gain of electrons.
Steps:
1. Oxidation: lose electrons.
2. Reduction: gain electrons.
3. They always occur together. | redox |
Oxidace je ztráta elektronů a redukce jejich zisk; probíhají vždy současně. | null | che_0040 | concept | cs | Co je oxidace a redukce? | [
"Oxidace: odevzdání elektronů.",
"Redukce: přijetí elektronů.",
"Příklad: Zn + Cu2+ -> Zn2+ + Cu."
] | chemistry | Answer: Ztráta versus zisk elektronů.
Steps:
1. Oxidace: odevzdání elektronů.
2. Redukce: přijetí elektronů.
3. Příklad: Zn + Cu2+ -> Zn2+ + Cu. | redox |
Sulfur has oxidation state +6, since 2(+1) + S + 4(-2) = 0 gives S = +6. | {
"A": "-2",
"B": "0",
"C": "+4",
"D": "+6"
} | che_0041 | multiple_choice | en | What is the oxidation state of sulfur in H2SO4? | [
"Assign H +1 and O -2.",
"Solve: 2 + S - 8 = 0.",
"S = +6; select D."
] | chemistry | Answer: +6.
Steps:
1. Assign H +1 and O -2.
2. Solve: 2 + S - 8 = 0.
3. S = +6; select D.
Answer: (D) | redox |
Manganese is +7, since +1 + Mn + 4(-2) = 0 gives Mn = +7. | null | che_0042 | worked_example | en | Find the oxidation number of Mn in KMnO4. | [
"Assign K +1 and O -2.",
"Equation: 1 + Mn - 8 = 0.",
"Mn = +7."
] | chemistry | Answer: +7.
Steps:
1. Assign K +1 and O -2.
2. Equation: 1 + Mn - 8 = 0.
3. Mn = +7. | redox |
The oxidizing agent is reduced while the reducing agent is oxidized in the reaction. | null | che_0043 | concept | en | How do oxidizing and reducing agents change? | [
"Oxidizing agent gains electrons.",
"Reducing agent loses electrons.",
"Example: Cu2+ oxidizes Zn."
] | chemistry | Answer: Oxidizer is reduced; reducer is oxidized.
Steps:
1. Oxidizing agent gains electrons.
2. Reducing agent loses electrons.
3. Example: Cu2+ oxidizes Zn. | redox |
The reduced species gains electrons, so its oxidation number decreases. | {
"A": "Loses electrons",
"B": "Gains electrons",
"C": "Loses protons",
"D": "Gains protons"
} | che_0044 | multiple_choice | en | What happens to the species being reduced? | [
"Recall reduction means gain.",
"Electrons are gained.",
"Select option B."
] | chemistry | Answer: Gains electrons.
Steps:
1. Recall reduction means gain.
2. Electrons are gained.
3. Select option B.
Answer: (B) | redox |
The balanced equation is 4Fe + 3O2 -> 2Fe2O3. | null | che_0045 | worked_example | en | Balance: Fe + O2 -> Fe2O3. | [
"Balance Fe with 2 Fe2O3 and 4 Fe.",
"Count O: 6 atoms each side.",
"Use 3 O2: 4Fe + 3O2 -> 2Fe2O3."
] | chemistry | Answer: 4Fe + 3O2 -> 2Fe2O3.
Steps:
1. Balance Fe with 2 Fe2O3 and 4 Fe.
2. Count O: 6 atoms each side.
3. Use 3 O2: 4Fe + 3O2 -> 2Fe2O3. | redox |
Chrom má oxidační číslo +6, protože 2 + 2Cr - 14 = 0 dává Cr = +6. | null | che_0046 | worked_example | cs | Urči oxidační číslo chromu v K2Cr2O7. | [
"Přiřaď K +1 a O -2.",
"Rovnice: 2 + 2Cr - 14 = 0.",
"Cr = +6."
] | chemistry | Answer: +6.
Steps:
1. Přiřaď K +1 a O -2.
2. Rovnice: 2 + 2Cr - 14 = 0.
3. Cr = +6. | redox |
Zinc dissolves in acid because it sits above hydrogen in the activity series, unlike copper or silver. | {
"A": "Cu",
"B": "Ag",
"C": "Zn",
"D": "Au"
} | che_0047 | multiple_choice | en | Which metal is oxidized by H+ from dilute acid? | [
"Recall only metals above H react.",
"Eliminate Cu, Ag, Au.",
"Select option C."
] | chemistry | Answer: Zn.
Steps:
1. Recall only metals above H react.
2. Eliminate Cu, Ag, Au.
3. Select option C.
Answer: (C) | redox |
The activity series ranks metals by ease of oxidation, predicting single-replacement outcomes. | null | che_0048 | concept | en | What is the metal activity series? | [
"Rank by tendency to oxidize.",
"Higher metals displace lower ions.",
"Example: Zn displaces Cu2+."
] | chemistry | Answer: Ranking of metals by reactivity.
Steps:
1. Rank by tendency to oxidize.
2. Higher metals displace lower ions.
3. Example: Zn displaces Cu2+. | redox |
Four electrons transfer: each Mg loses 2 and the O2 molecule gains 4 total. | null | che_0049 | worked_example | en | How many electrons transfer in 2Mg + O2 -> 2MgO? | [
"Each Mg: 0 -> +2, loses 2.",
"Two Mg lose 4 total.",
"O2 gains 4; transfer = 4 e-."
] | chemistry | Answer: 4 electrons.
Steps:
1. Each Mg: 0 -> +2, loses 2.
2. Two Mg lose 4 total.
3. O2 gains 4; transfer = 4 e-. | redox |
Chlorine is both oxidized and reduced in Cl2 + H2O -> Cl- + ClO- + 2H+, a disproportionation. | {
"A": "Cl2 -> Cl- plus ClO-",
"B": "Zn + Cu2+ -> Zn2+ + Cu",
"C": "HCl + NaOH -> NaCl + H2O",
"D": "Ag+ + Cl- -> AgCl"
} | che_0050 | multiple_choice | en | Which reaction is a disproportionation? | [
"Need one element both oxidized and reduced.",
"Only chlorine qualifies.",
"Select option A."
] | chemistry | Answer: Cl2 -> Cl- plus ClO-.
Steps:
1. Need one element both oxidized and reduced.
2. Only chlorine qualifies.
3. Select option A.
Answer: (A) | redox |
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