answer string | choices dict | id string | kind string | lang string | question string | steps list | subject string | text string | topic string |
|---|---|---|---|---|---|---|---|---|---|
The atomic mass unit is 1/12 the mass of a carbon-12 atom. | null | che_0751 | concept | en | What is the atomic mass unit? | [
"Based on carbon-12.",
"One unit is 1/12 of it.",
"Equals 1.661e-27 kg."
] | chemistry | Answer: 1/12 of carbon-12.
Steps:
1. Based on carbon-12.
2. One unit is 1/12 of it.
3. Equals 1.661e-27 kg. | stoichiometry |
One amu is defined as 1/12 the mass of a carbon-12 atom. | {
"A": "1 gram",
"B": "1/12 of carbon-12",
"C": "1 mole",
"D": "1 liter"
} | che_0752 | multiple_choice | en | What does 1 amu equal? | [
"Carbon-12 standard.",
"Divide by 12.",
"Select option B."
] | chemistry | Answer: 1/12 of carbon-12.
Steps:
1. Carbon-12 standard.
2. Divide by 12.
3. Select option B.
Answer: (B) | stoichiometry |
The mass is 100.90 g, from 5.00 mol times 20.180 g/mol. | null | che_0753 | worked_example | en | What mass is 5.00 mol of neon (M = 20.180 g/mol)? | [
"Write: m = 5.00 x 20.180.",
"Multiply.",
"m = 100.90 g."
] | chemistry | Answer: 100.90 g.
Steps:
1. Write: m = 5.00 x 20.180.
2. Multiply.
3. m = 100.90 g. | stoichiometry |
Atomová hmotnostní jednotka je 1/12 hmotnosti atomu uhlíku 12. | null | che_0754 | concept | cs | Co je atomová hmotnostní jednotka? | [
"Základ uhlík 12.",
"Jednotka je 1/12.",
"Rovná se 1,661e-27 kg."
] | chemistry | Answer: 1/12 uhlíku 12.
Steps:
1. Základ uhlík 12.
2. Jednotka je 1/12.
3. Rovná se 1,661e-27 kg. | stoichiometry |
There are 0.494 mol, from 12.0 g divided by 24.305 g/mol. | null | che_0755 | worked_example | en | How many moles are in 12.0 g of magnesium (M = 24.305 g/mol)? | [
"Write: n = 12.0/24.305.",
"Divide.",
"n = 0.494 mol."
] | chemistry | Answer: 0.494 mol.
Steps:
1. Write: n = 12.0/24.305.
2. Divide.
3. n = 0.494 mol. | stoichiometry |
Ammonia totals 17.03 g/mol from 1 N and 3 H. | {
"A": "14.01 g/mol",
"B": "16.04 g/mol",
"C": "17.03 g/mol",
"D": "18.02 g/mol"
} | che_0756 | multiple_choice | en | What is the molar mass of NH3? | [
"14.01 + 3x1.008.",
"Total 17.03.",
"Select option C."
] | chemistry | Answer: 17.03 g/mol.
Steps:
1. 14.01 + 3x1.008.
2. Total 17.03.
3. Select option C.
Answer: (C) | stoichiometry |
Mass spectrometry weighs isotopes to give average atomic masses. | null | che_0757 | concept | en | How does mass spectrometry give atomic mass? | [
"Ions sort by mass.",
"Abundances measured.",
"Weighted average taken."
] | chemistry | Answer: Weighted isotope average.
Steps:
1. Ions sort by mass.
2. Abundances measured.
3. Weighted average taken. | stoichiometry |
There are 1.00 x 10^23 atoms, from 0.1665 mol times Avogadro's number. | null | che_0758 | worked_example | en | How many atoms are in 2.00 g of carbon (M = 12.011 g/mol)? | [
"Moles = 2.00/12.011 = 0.1665.",
"Multiply: 0.1665 x 6.022 x 10^23.",
"N = 1.00 x 10^23."
] | chemistry | Answer: 1.00 x 10^23.
Steps:
1. Moles = 2.00/12.011 = 0.1665.
2. Multiply: 0.1665 x 6.022 x 10^23.
3. N = 1.00 x 10^23. | stoichiometry |
Hmotnost je 41,44 g, protože 0,2 krát 207,2 se rovná 41,44. | null | che_0759 | worked_example | cs | Jaká je hmotnost 0,2 molu olova (M = 207,2 g/mol)? | [
"Napiš vzorec: m = 0,2 x 207,2.",
"Vynásob.",
"m = 41,44 g."
] | chemistry | Answer: 41,44 g.
Steps:
1. Napiš vzorec: m = 0,2 x 207,2.
2. Vynásob.
3. m = 41,44 g. | stoichiometry |
The balanced equation is H2 + Cl2 -> 2HCl. | {
"A": "1, 1, 2",
"B": "2, 1, 2",
"C": "1, 2, 2",
"D": "2, 2, 2"
} | che_0760 | multiple_choice | en | What coefficients balance H2 + Cl2 -> HCl? | [
"H: 2 HCl.",
"Cl: 2 HCl.",
"Select option A."
] | chemistry | Answer: 1, 1, 2.
Steps:
1. H: 2 HCl.
2. Cl: 2 HCl.
3. Select option A.
Answer: (A) | stoichiometry |
The CO2 mass is 33.0 g, from 0.75 mol times 44.01 g/mol. | null | che_0761 | worked_example | en | What mass of CO2 forms from 0.25 mol of propane (C3H8 + 5O2 -> 3CO2 + 4H2O)? | [
"Moles CO2 = 0.25 x 3 = 0.75.",
"Multiply: 0.75 x 44.01.",
"Mass = 33.0 g."
] | chemistry | Answer: 33.0 g.
Steps:
1. Moles CO2 = 0.25 x 3 = 0.75.
2. Multiply: 0.75 x 44.01.
3. Mass = 33.0 g. | stoichiometry |
Atom economy is the share of reactant mass ending in the desired product. | null | che_0762 | concept | en | What is atom economy? | [
"Divide product mass by reactants.",
"Times 100 percent.",
"Higher means greener."
] | chemistry | Answer: Product share of mass.
Steps:
1. Divide product mass by reactants.
2. Times 100 percent.
3. Higher means greener. | stoichiometry |
Full atom economy means every reactant atom lands in the product. | {
"A": "No product forms",
"B": "Half is waste",
"C": "Gas evolves",
"D": "All atoms in product"
} | che_0763 | multiple_choice | en | What does 100% atom economy mean? | [
"No atoms wasted.",
"All in desired product.",
"Select option D."
] | chemistry | Answer: All atoms in product.
Steps:
1. No atoms wasted.
2. All in desired product.
3. Select option D.
Answer: (D) | stoichiometry |
Limitující reaktant určíš porovnáním poměrů molů ke koeficientům. | null | che_0764 | concept | cs | Jak se určí limitující reaktant? | [
"Vyděl moly koeficientem.",
"Nejmenší podíl limituje.",
"Ten určí výtěžek."
] | chemistry | Answer: Nejmenším poměrem molů.
Steps:
1. Vyděl moly koeficientem.
2. Nejmenší podíl limituje.
3. Ten určí výtěžek. | stoichiometry |
The ammonia mass is 56.3 g, from 3.307 mol times 17.031 g/mol. | null | che_0765 | worked_example | en | What mass of NH3 forms from 10.0 g H2 with excess N2? | [
"Moles H2 = 10.0/2.016 = 4.960.",
"NH3 = 4.960 x 2/3 = 3.307 mol.",
"Mass = 3.307 x 17.031 = 56.3 g."
] | chemistry | Answer: 56.3 g.
Steps:
1. Moles H2 = 10.0/2.016 = 4.960.
2. NH3 = 4.960 x 2/3 = 3.307 mol.
3. Mass = 3.307 x 17.031 = 56.3 g. | stoichiometry |
Molality counts moles per kilogram of solvent, unlike molarity per liter of solution. | {
"A": "L of solution",
"B": "kg of solvent",
"C": "kg of solution",
"D": "L of solvent"
} | che_0766 | multiple_choice | en | How is molality defined? | [
"Moles of solute.",
"Per kg of solvent.",
"Select option B."
] | chemistry | Answer: kg of solvent.
Steps:
1. Moles of solute.
2. Per kg of solvent.
3. Select option B.
Answer: (B) | stoichiometry |
The molality is 0.500 m, from 1.00 mol divided by 2.00 kg. | null | che_0767 | worked_example | en | 1.00 mol of NaCl dissolves in 2.00 kg of water. Find molality. | [
"Write: m = 1.00/2.00.",
"Divide.",
"m = 0.500 mol/kg."
] | chemistry | Answer: 0.500 m.
Steps:
1. Write: m = 1.00/2.00.
2. Divide.
3. m = 0.500 mol/kg. | stoichiometry |
Objem je 44,8 l, protože 2 krát 22,414 se rovná 44,828. | null | che_0768 | worked_example | cs | Jaký objem mají 2 moly plynu za normálních podmínek? | [
"Napiš vzorec: V = 2 x 22,414.",
"Vynásob.",
"V = 44,8 l."
] | chemistry | Answer: 44,8 l.
Steps:
1. Napiš vzorec: V = 2 x 22,414.
2. Vynásob.
3. V = 44,8 l. | stoichiometry |
The volume is 11.2 L, from 0.500 mol times 22.414 L/mol. | {
"A": "11.2 L",
"B": "22.4 L",
"C": "5.6 L",
"D": "44.8 L"
} | che_0769 | multiple_choice | en | What volume does 0.500 mol of gas occupy at STP? | [
"Multiply: 0.500 x 22.414.",
"Result 11.2 L.",
"Select option A."
] | chemistry | Answer: 11.2 L.
Steps:
1. Multiply: 0.500 x 22.414.
2. Result 11.2 L.
3. Select option A.
Answer: (A) | stoichiometry |
The hydronium ion H3O+ is a proton bound to a water molecule. | null | che_0770 | concept | en | What is the hydronium ion? | [
"H+ joins H2O.",
"Forms H3O+.",
"True form of acidity."
] | chemistry | Answer: H+ bound to water.
Steps:
1. H+ joins H2O.
2. Forms H3O+.
3. True form of acidity. | acids_bases |
Free protons hydrate instantly to H3O+ in water. | {
"A": "Bare H+",
"B": "H2 gas",
"C": "H3O+",
"D": "OH-"
} | che_0771 | multiple_choice | en | How does H+ exist in water? | [
"Protons hydrate.",
"Form is H3O+.",
"Select option C."
] | chemistry | Answer: H3O+.
Steps:
1. Protons hydrate.
2. Form is H3O+.
3. Select option C.
Answer: (C) | acids_bases |
The pH is 2.10, from -log(0.0080). | null | che_0772 | worked_example | en | Compute the pH of 0.0080 M HCl. | [
"[H+] = 0.0080 M.",
"pH = -log(0.0080).",
"pH = 2.10."
] | chemistry | Answer: 2.10.
Steps:
1. [H+] = 0.0080 M.
2. pH = -log(0.0080).
3. pH = 2.10. | acids_bases |
Hydroniový ion H3O+ je proton navázaný na molekulu vody. | null | che_0773 | concept | cs | Co je hydroniový ion? | [
"H+ se váže na H2O.",
"Vzniká H3O+.",
"Skutečná forma kyselosti."
] | chemistry | Answer: H+ navázaný na vodu.
Steps:
1. H+ se váže na H2O.
2. Vzniká H3O+.
3. Skutečná forma kyselosti. | acids_bases |
Removing a proton from H3O+ leaves water, H2O. | {
"A": "OH(-)",
"B": "H2O",
"C": "O2(-)",
"D": "H2"
} | che_0774 | multiple_choice | en | What is the conjugate base of H3O+? | [
"Remove one H+.",
"Left with H2O.",
"Select option B."
] | chemistry | Answer: H2O.
Steps:
1. Remove one H+.
2. Left with H2O.
3. Select option B.
Answer: (B) | acids_bases |
Hydroxide concentration is 1.0 x 10^-11 M, from pOH = 14 - 3 = 11. | null | che_0775 | worked_example | en | A solution has pH 3.00. Compute [OH-]. | [
"pOH = 14 - 3.00 = 11.00.",
"Write: [OH-] = 10^(-11).",
"[OH-] = 1.0 x 10^-11 M."
] | chemistry | Answer: 1.0 x 10^-11 M.
Steps:
1. pOH = 14 - 3.00 = 11.00.
2. Write: [OH-] = 10^(-11).
3. [OH-] = 1.0 x 10^-11 M. | acids_bases |
A strong acid has a weak conjugate base, and vice versa. | null | che_0776 | concept | en | How are acid and conjugate base strengths related? | [
"Strong acid donates easily.",
"Its base holds H+ weakly.",
"Ka x Kb = Kw proves it."
] | chemistry | Answer: Inversely related strengths.
Steps:
1. Strong acid donates easily.
2. Its base holds H+ weakly.
3. Ka x Kb = Kw proves it. | acids_bases |
Kb is 5.6 x 10^-10, from 1.0 x 10^-14 divided by 1.8 x 10^-5. | null | che_0777 | worked_example | en | An acid has Ka = 1.8 x 10^-5. Compute Kb of its conjugate base. | [
"Write: Kb = Kw/Ka.",
"Substitute: 1.0e-14/1.8e-5.",
"Kb = 5.6 x 10^-10."
] | chemistry | Answer: 5.6 x 10^-10.
Steps:
1. Write: Kb = Kw/Ka.
2. Substitute: 1.0e-14/1.8e-5.
3. Kb = 5.6 x 10^-10. | acids_bases |
The product Ka x Kb always equals Kw = 1.0 x 10^-14. | {
"A": "1.0 x 10^-14",
"B": "14",
"C": "1.0",
"D": "0"
} | che_0778 | multiple_choice | en | What is Ka x Kb for NH4+/NH3 at 25 C? | [
"Conjugate pair rule.",
"Product equals Kw.",
"Select option A."
] | chemistry | Answer: 1.0 x 10^-14.
Steps:
1. Conjugate pair rule.
2. Product equals Kw.
3. Select option A.
Answer: (A) | acids_bases |
pH je 2,40, protože -log(0,004) = 2,40. | null | che_0779 | worked_example | cs | Vypočítej pH roztoku 0,004 M HCl. | [
"HCl disociuje plně.",
"pH = -log(0,004).",
"pH = 2,40."
] | chemistry | Answer: 2,40.
Steps:
1. HCl disociuje plně.
2. pH = -log(0,004).
3. pH = 2,40. | acids_bases |
Salt ions from weak acids or bases react with water to shift pH. | null | che_0780 | concept | en | Why do some salts change pH? | [
"Weak-parent ions hydrolyze.",
"H+ or OH- released.",
"Strong-parent ions stay neutral."
] | chemistry | Answer: Hydrolysis of weak-parent ions.
Steps:
1. Weak-parent ions hydrolyze.
2. H+ or OH- released.
3. Strong-parent ions stay neutral. | acids_bases |
Both ions come from strong parents, so neither hydrolyzes. | {
"A": "Acidic",
"B": "Neutral",
"C": "Basic",
"D": "Cannot tell"
} | che_0781 | multiple_choice | en | Is NaCl solution acidic or basic? | [
"Na+ from strong base.",
"Cl- from strong acid.",
"Select option B."
] | chemistry | Answer: Neutral.
Steps:
1. Na+ from strong base.
2. Cl- from strong acid.
3. Select option B.
Answer: (B) | acids_bases |
The buffer pH is 3.76, from 4.76 + log(0.1). | null | che_0782 | worked_example | en | An acetate buffer (pKa = 4.76) has base/acid = 0.10. Find pH. | [
"Write: pH = 4.76 + log(0.10).",
"log(0.10) = -1.",
"pH = 3.76."
] | chemistry | Answer: 3.76.
Steps:
1. Write: pH = 4.76 + log(0.10).
2. log(0.10) = -1.
3. pH = 3.76. | acids_bases |
Buffers are made by mixing a weak acid with its conjugate salt. | null | che_0783 | concept | en | How are buffers prepared? | [
"Pick acid near target pH.",
"Add its salt.",
"Ratio sets exact pH."
] | chemistry | Answer: Weak acid plus its salt.
Steps:
1. Pick acid near target pH.
2. Add its salt.
3. Ratio sets exact pH. | acids_bases |
Hydrolýza solí je reakce iontů soli s vodou měnící pH. | null | che_0784 | concept | cs | Co je hydrolýza solí? | [
"Ionty reagují s vodou.",
"Vzniká H+ nebo OH-.",
"Silné páry nereagují."
] | chemistry | Answer: Reakce iontů s vodou.
Steps:
1. Ionty reagují s vodou.
2. Vzniká H+ nebo OH-.
3. Silné páry nereagují. | acids_bases |
The conjugate base hydrolyzes, leaving excess OH- above pH 7. | {
"A": "pH 7",
"B": "Below 7",
"C": "Above 7",
"D": "pH 1"
} | che_0785 | multiple_choice | en | What is the equivalence pH of weak acid with strong base? | [
"Salt of weak acid forms.",
"Anion makes OH-.",
"Select option C."
] | chemistry | Answer: Above 7.
Steps:
1. Salt of weak acid forms.
2. Anion makes OH-.
3. Select option C.
Answer: (C) | acids_bases |
There are 10.0 mmol, from 25.0 mL times 0.400 M. | null | che_0786 | worked_example | en | How many millimoles are in 25.0 mL of 0.400 M NaOH? | [
"Write: mmol = 25.0 x 0.400.",
"Multiply.",
"mmol = 10.0."
] | chemistry | Answer: 10.0 mmol.
Steps:
1. Write: mmol = 25.0 x 0.400.
2. Multiply.
3. mmol = 10.0. | acids_bases |
[OH-] je 1 x 10^-2 M, protože pOH = 14 - 12 = 2. | null | che_0787 | worked_example | cs | Roztok má pH 12. Vypočítej [OH-]. | [
"pOH = 14 - 12 = 2.",
"Napiš vzorec: [OH-] = 10^(-2).",
"[OH-] = 1 x 10^-2 M."
] | chemistry | Answer: 1 x 10^-2 M.
Steps:
1. pOH = 14 - 12 = 2.
2. Napiš vzorec: [OH-] = 10^(-2).
3. [OH-] = 1 x 10^-2 M. | acids_bases |
Cyanide hydrolyzes to make OH-, so the solution is basic. | {
"A": "Basic",
"B": "Acidic",
"C": "Neutral",
"D": "Cannot tell"
} | che_0788 | multiple_choice | en | Is KCN solution acidic or basic? | [
"CN- from weak HCN.",
"It makes OH-.",
"Select option A."
] | chemistry | Answer: Basic.
Steps:
1. CN- from weak HCN.
2. It makes OH-.
3. Select option A.
Answer: (A) | acids_bases |
Hydrogen is +1 except in metal hydrides, where it is -1. | null | che_0789 | concept | en | When is hydrogen's oxidation state negative? | [
"Normal rule: H is +1.",
"Metals less electronegative.",
"In hydrides H is -1."
] | chemistry | Answer: In metal hydrides.
Steps:
1. Normal rule: H is +1.
2. Metals less electronegative.
3. In hydrides H is -1. | redox |
Calcium is +2, so each H must be -1 to balance. | {
"A": "+1",
"B": "-1",
"C": "0",
"D": "+2"
} | che_0790 | multiple_choice | en | What is the oxidation state of H in CaH2? | [
"Ca is +2.",
"Solve: 2 + 2H = 0.",
"H = -1; select B."
] | chemistry | Answer: -1.
Steps:
1. Ca is +2.
2. Solve: 2 + 2H = 0.
3. H = -1; select B.
Answer: (B) | redox |
Boron is +3, since 3(+1) + B + 3(-2) = 0. | null | che_0791 | worked_example | en | Find the oxidation number of B in H3BO3. | [
"Assign H +1 and O -2.",
"Equation: 3 + B - 6 = 0.",
"B = +3."
] | chemistry | Answer: +3.
Steps:
1. Assign H +1 and O -2.
2. Equation: 3 + B - 6 = 0.
3. B = +3. | redox |
Redukční činidlo odevzdává elektrony a samo se oxiduje. | null | che_0792 | concept | cs | Co je redukční činidlo? | [
"Odevzdává elektrony.",
"Samo se oxiduje.",
"Příklad: Zn, H2."
] | chemistry | Answer: Dárce elektronů.
Steps:
1. Odevzdává elektrony.
2. Samo se oxiduje.
3. Příklad: Zn, H2. | redox |
Magnesium loses electrons to oxygen, so it is the reducing agent. | {
"A": "Mg",
"B": "O2",
"C": "MgO",
"D": "Heat"
} | che_0793 | multiple_choice | en | In 2Mg + O2 -> 2MgO, what is the reducing agent? | [
"Mg is oxidized.",
"Oxidized species reduces.",
"Select option A."
] | chemistry | Answer: Mg.
Steps:
1. Mg is oxidized.
2. Oxidized species reduces.
3. Select option A.
Answer: (A) | redox |
The balanced equation is C + 2H2 -> CH4. | null | che_0794 | worked_example | en | Balance: C + H2 -> CH4. | [
"Balance H with 2 H2.",
"Check C: 1 each side.",
"Result: C + 2H2 -> CH4."
] | chemistry | Answer: C + 2H2 -> CH4.
Steps:
1. Balance H with 2 H2.
2. Check C: 1 each side.
3. Result: C + 2H2 -> CH4. | redox |
Balance first as in acid, then neutralize H+ with OH- into water. | null | che_0795 | concept | en | How is redox balanced in basic solution? | [
"Balance as in acid.",
"Add OH- to both sides.",
"Combine H+ and OH- to H2O."
] | chemistry | Answer: Acid method plus OH- fix.
Steps:
1. Balance as in acid.
2. Add OH- to both sides.
3. Combine H+ and OH- to H2O. | redox |
Three electrons are gained as nitrogen drops from +5 to +2. | null | che_0796 | worked_example | en | How many electrons are gained in NO3- -> NO? | [
"N goes +5 to +2.",
"Change = 3 down.",
"Electrons gained = 3."
] | chemistry | Answer: 3 electrons.
Steps:
1. N goes +5 to +2.
2. Change = 3 down.
3. Electrons gained = 3. | redox |
Chlorine gains electrons to form chloride, so Cl2 is reduced. | {
"A": "Na",
"B": "NaCl",
"C": "Cl2",
"D": "None"
} | che_0797 | multiple_choice | en | In 2Na + Cl2 -> 2NaCl, what is reduced? | [
"Cl goes 0 to -1.",
"That is reduction.",
"Select option C."
] | chemistry | Answer: Cl2.
Steps:
1. Cl goes 0 to -1.
2. That is reduction.
3. Select option C.
Answer: (C) | redox |
Uhlík má oxidační číslo +2, protože C + (-2) = 0. | null | che_0798 | worked_example | cs | Urči oxidační číslo uhlíku v CO. | [
"Přiřaď O -2.",
"Rovnice: C - 2 = 0.",
"C = +2."
] | chemistry | Answer: +2.
Steps:
1. Přiřaď O -2.
2. Rovnice: C - 2 = 0.
3. C = +2. | redox |
Smelting reduces metal oxides with carbon or CO to free metals. | null | che_0799 | concept | en | How does smelting extract metals? | [
"Heat oxide ore.",
"Carbon reduces it.",
"Metal melts out."
] | chemistry | Answer: Carbon reduces ore oxides.
Steps:
1. Heat oxide ore.
2. Carbon reduces it.
3. Metal melts out. | redox |
Coke provides CO that reduces iron ore in the blast furnace. | {
"A": "Oxygen",
"B": "Coke",
"C": "Water",
"D": "Acid"
} | che_0800 | multiple_choice | en | What reduces iron ore in a blast furnace? | [
"Need a reducer.",
"Coke supplies CO.",
"Select option B."
] | chemistry | Answer: Coke.
Steps:
1. Need a reducer.
2. Coke supplies CO.
3. Select option B.
Answer: (B) | redox |
The balanced equation is TiCl4 + 2Mg -> Ti + 2MgCl2. | null | che_0801 | worked_example | en | Balance: TiCl4 + Mg -> Ti + MgCl2. | [
"Balance Cl with 2 MgCl2.",
"Balance Mg with 2 Mg.",
"Result: TiCl4 + 2Mg -> Ti + 2MgCl2."
] | chemistry | Answer: TiCl4 + 2Mg -> Ti + 2MgCl2.
Steps:
1. Balance Cl with 2 MgCl2.
2. Balance Mg with 2 Mg.
3. Result: TiCl4 + 2Mg -> Ti + 2MgCl2. | redox |
V metalurgii se oxidace používá k pražení a redukce k získání kovu. | null | che_0802 | concept | cs | Jak se redox používá v metalurgii? | [
"Pražení: oxidace sulfidů.",
"Tavení: redukce oxidů.",
"Výsledek: čistý kov."
] | chemistry | Answer: Pražení a redukce rud.
Steps:
1. Pražení: oxidace sulfidů.
2. Tavení: redukce oxidů.
3. Výsledek: čistý kov. | redox |
Phosphorus is +5, since 2P + 5(-2) = 0 gives P = +5. | {
"A": "+2",
"B": "+3",
"C": "+4",
"D": "+5"
} | che_0803 | multiple_choice | en | What is the oxidation state of P in P2O5? | [
"Assign O -2.",
"Solve: 2P - 10 = 0.",
"P = +5; select D."
] | chemistry | Answer: +5.
Steps:
1. Assign O -2.
2. Solve: 2P - 10 = 0.
3. P = +5; select D.
Answer: (D) | redox |
Redox indicators change color at a specific electrode potential. | null | che_0804 | concept | en | What are redox indicators? | [
"Oxidized form one color.",
"Reduced form another.",
"Flip marks endpoint."
] | chemistry | Answer: Color at set potential.
Steps:
1. Oxidized form one color.
2. Reduced form another.
3. Flip marks endpoint. | redox |
Vyčíslená rovnice je 2Ag2O -> 4Ag + O2. | null | che_0805 | worked_example | cs | Vyčísli: Ag2O -> Ag + O2. | [
"Kyslík: 2 Ag2O a 1 O2.",
"Stříbro: 4 Ag.",
"Výsledek: 2Ag2O -> 4Ag + O2."
] | chemistry | Answer: 2Ag2O -> 4Ag + O2.
Steps:
1. Kyslík: 2 Ag2O a 1 O2.
2. Stříbro: 4 Ag.
3. Výsledek: 2Ag2O -> 4Ag + O2. | redox |
The Mn2+ ion has manganese at +2 by its charge. | {
"A": "+2",
"B": "+4",
"C": "+7",
"D": "0"
} | che_0806 | multiple_choice | en | What is the oxidation state of Mn in Mn2+? | [
"Monoatomic ion rule.",
"State equals charge.",
"Select option A."
] | chemistry | Answer: +2.
Steps:
1. Monoatomic ion rule.
2. State equals charge.
3. Select option A.
Answer: (A) | redox |
Two electrons are lost as copper goes from 0 to +2. | null | che_0807 | worked_example | en | How many electrons are lost in Cu -> Cu2+? | [
"Change: 0 to +2.",
"Difference = 2 up.",
"Electrons lost = 2."
] | chemistry | Answer: 2 electrons.
Steps:
1. Change: 0 to +2.
2. Difference = 2 up.
3. Electrons lost = 2. | redox |
Heat is energy in transit while temperature measures average particle energy. | null | che_0808 | concept | en | How do heat and temperature differ? | [
"Heat flows between bodies.",
"Temperature is intensity.",
"Same T can hold more heat."
] | chemistry | Answer: Energy flow versus intensity.
Steps:
1. Heat flows between bodies.
2. Temperature is intensity.
3. Same T can hold more heat. | thermochemistry |
Temperature reflects the average kinetic energy of particles. | {
"A": "Total mass",
"B": "Total volume",
"C": "Average kinetic energy",
"D": "Total charge"
} | che_0809 | multiple_choice | en | What does temperature measure? | [
"Faster particles mean hotter.",
"Average kinetic energy.",
"Select option C."
] | chemistry | Answer: Average kinetic energy.
Steps:
1. Faster particles mean hotter.
2. Average kinetic energy.
3. Select option C.
Answer: (C) | thermochemistry |
The internal energy change is -150 J, from -100 plus -50 J. | null | che_0810 | worked_example | en | A system releases 100 J of heat and does 50 J of work. Find ΔU. | [
"Write: ΔU = -100 + (-50).",
"Add.",
"ΔU = -150 J."
] | chemistry | Answer: -150 J.
Steps:
1. Write: ΔU = -100 + (-50).
2. Add.
3. ΔU = -150 J. | thermochemistry |
Teplota je míra průměrné kinetické energie částic. | null | che_0811 | concept | cs | Co je teplota? | [
"Průměrná energie částic.",
"Měří se teploměrem.",
"Jednotky: °C, K."
] | chemistry | Answer: Míra energie částic.
Steps:
1. Průměrná energie částic.
2. Měří se teploměrem.
3. Jednotky: °C, K. | thermochemistry |
The SI unit of heat energy is the joule. | {
"A": "Joule",
"B": "Watt",
"C": "Newton",
"D": "Pascal"
} | che_0812 | multiple_choice | en | What is the SI unit of heat? | [
"Heat is energy.",
"Energy unit is joule.",
"Select option A."
] | chemistry | Answer: Joule.
Steps:
1. Heat is energy.
2. Energy unit is joule.
3. Select option A.
Answer: (A) | thermochemistry |
The heat is 20.9 kJ, from 1000 g x 4.184 x 5. | null | che_0813 | worked_example | en | How much heat warms 1.00 kg of water by 5.00 C? | [
"Write: q = 1000 x 4.184 x 5.",
"Multiply: 20,920 J.",
"q = 20.9 kJ."
] | chemistry | Answer: 20.9 kJ.
Steps:
1. Write: q = 1000 x 4.184 x 5.
2. Multiply: 20,920 J.
3. q = 20.9 kJ. | thermochemistry |
Metals heat quickly because their specific heats are low. | null | che_0814 | concept | en | Why do metals heat faster than water? | [
"Low specific heat.",
"Little energy per degree.",
"Example: Al 0.897 J/gC."
] | chemistry | Answer: Low specific heat.
Steps:
1. Low specific heat.
2. Little energy per degree.
3. Example: Al 0.897 J/gC. | thermochemistry |
The rise is 26.0 C, from 2000 J divided by (200 x 0.385). | null | che_0815 | worked_example | en | 200 g of Cu (c = 0.385 J/gC) gains 2000 J. Find ΔT. | [
"Write: ΔT = 2000/(200 x 0.385).",
"Divide: 2000/77.",
"ΔT = 26.0 C."
] | chemistry | Answer: 26.0 C.
Steps:
1. Write: ΔT = 2000/(200 x 0.385).
2. Divide: 2000/77.
3. ΔT = 26.0 C. | thermochemistry |
Water's hydrogen bonding gives it the highest common specific heat. | {
"A": "Iron",
"B": "Water",
"C": "Copper",
"D": "Lead"
} | che_0816 | multiple_choice | en | Which has the highest specific heat? | [
"Water is 4.184 J/gC.",
"Metals far lower.",
"Select option B."
] | chemistry | Answer: Water.
Steps:
1. Water is 4.184 J/gC.
2. Metals far lower.
3. Select option B.
Answer: (B) | thermochemistry |
Potřebné teplo je 4184 J, protože 1000 x 4,184 x 1 se rovná 4184. | null | che_0817 | worked_example | cs | Kolik tepla ohřeje 1 kg vody o 1 °C? | [
"Napiš vzorec: q = 1000 x 4,184 x 1.",
"Vynásob.",
"q = 4184 J."
] | chemistry | Answer: 4184 J.
Steps:
1. Napiš vzorec: q = 1000 x 4,184 x 1.
2. Vynásob.
3. q = 4184 J. | thermochemistry |
Latent heat changes phase at constant temperature without a thermometer rise. | null | che_0818 | concept | en | What is latent heat? | [
"Heat for phase change.",
"Temperature stays flat.",
"Bonds rearrange instead."
] | chemistry | Answer: Heat of phase change.
Steps:
1. Heat for phase change.
2. Temperature stays flat.
3. Bonds rearrange instead. | thermochemistry |
Phase changes absorb or release heat while temperature holds steady. | {
"A": "Rising T",
"B": "Falling T",
"C": "Any T",
"D": "Constant T"
} | che_0819 | multiple_choice | en | At what temperature does latent heat act? | [
"Phase change plateau.",
"T stays fixed.",
"Select option D."
] | chemistry | Answer: Constant T.
Steps:
1. Phase change plateau.
2. T stays fixed.
3. Select option D.
Answer: (D) | thermochemistry |
The overall ΔH is +50 kJ, from +20 plus +30 kJ. | null | che_0820 | worked_example | en | A->B has ΔH = +20 kJ and B->C has ΔH = +30 kJ. Find ΔH for A->C. | [
"Apply Hess's law: sum steps.",
"Add: 20 + 30.",
"ΔH = +50 kJ."
] | chemistry | Answer: +50 kJ.
Steps:
1. Apply Hess's law: sum steps.
2. Add: 20 + 30.
3. ΔH = +50 kJ. | thermochemistry |
Skupenské teplo je teplo potřebné ke změně skupenství při stálé teplotě. | null | che_0821 | concept | cs | Co je skupenské teplo? | [
"Teplo fázové změny.",
"Teplota se nemění.",
"Příklady: tání, var."
] | chemistry | Answer: Teplo změny skupenství.
Steps:
1. Teplo fázové změny.
2. Teplota se nemění.
3. Příklady: tání, var. | thermochemistry |
Sublimation absorbs heat to free molecules directly into gas. | {
"A": "Endothermic",
"B": "Exothermic",
"C": "Athermal",
"D": "Nuclear"
} | che_0822 | multiple_choice | en | Is sublimation endothermic or exothermic? | [
"Bonds break to gas.",
"Breaking needs energy.",
"Select option A."
] | chemistry | Answer: Endothermic.
Steps:
1. Bonds break to gas.
2. Breaking needs energy.
3. Select option A.
Answer: (A) | thermochemistry |
ΔG is -90 kJ, from -60 minus 300 x 0.100. | null | che_0823 | worked_example | en | ΔH = -60 kJ and ΔS = +0.100 kJ/K at 300 K. Compute ΔG. | [
"Write: ΔG = -60 - 300 x 0.100.",
"Simplify: -60 - 30.",
"ΔG = -90 kJ."
] | chemistry | Answer: -90 kJ.
Steps:
1. Write: ΔG = -60 - 300 x 0.100.
2. Simplify: -60 - 30.
3. ΔG = -90 kJ. | thermochemistry |
Samovolný děj probíhá bez vnějšího přísunu energie. | null | che_0824 | concept | cs | Co je samovolný děj? | [
"Běží sám od sebe.",
"ΔG je záporné.",
"Může být pomalý."
] | chemistry | Answer: Děj bez vnější energie.
Steps:
1. Běží sám od sebe.
2. ΔG je záporné.
3. Může být pomalý. | thermochemistry |
Positive ΔG means the process needs driving and is nonspontaneous. | {
"A": "Spontaneous",
"B": "Nonspontaneous",
"C": "At equilibrium",
"D": "Impossible"
} | che_0825 | multiple_choice | en | What does ΔG > 0 mean? | [
"Free energy rises.",
"Needs external drive.",
"Select option B."
] | chemistry | Answer: Nonspontaneous.
Steps:
1. Free energy rises.
2. Needs external drive.
3. Select option B.
Answer: (B) | thermochemistry |
Vaporizing needs 77.2 kJ, from 2.00 mol times 38.6 kJ/mol. | null | che_0826 | worked_example | en | How much heat vaporizes 2.00 mol of ethanol (ΔHvap = 38.6 kJ/mol)? | [
"Write: q = 2.00 x 38.6.",
"Multiply.",
"q = 77.2 kJ."
] | chemistry | Answer: 77.2 kJ.
Steps:
1. Write: q = 2.00 x 38.6.
2. Multiply.
3. q = 77.2 kJ. | thermochemistry |
Substituents are listed alphabetically, ignoring di- and tri- prefixes. | null | che_0827 | concept | en | In what order are substituents listed? | [
"Sort alphabetically.",
"Ignore di-, tri-.",
"Example: ethyl before methyl."
] | chemistry | Answer: Alphabetical order.
Steps:
1. Sort alphabetically.
2. Ignore di-, tri-.
3. Example: ethyl before methyl. | organic_naming |
Ethyl comes before methyl alphabetically. | {
"A": "Methyl",
"B": "Ethyl",
"C": "Propyl",
"D": "Butyl"
} | che_0828 | multiple_choice | en | Which substituent is listed first? | [
"Compare first letters.",
"E beats M.",
"Select option B."
] | chemistry | Answer: Ethyl.
Steps:
1. Compare first letters.
2. E beats M.
3. Select option B.
Answer: (B) | organic_naming |
The name is 2-methylbutane: four carbons with a methyl on carbon 2. | null | che_0829 | worked_example | en | Name CH3CH(CH3)CH2CH3. | [
"Longest chain: 4 = butane.",
"Methyl on carbon 2.",
"Name: 2-methylbutane."
] | chemistry | Answer: 2-methylbutane.
Steps:
1. Longest chain: 4 = butane.
2. Methyl on carbon 2.
3. Name: 2-methylbutane. | organic_naming |
Substituenty se řadí abecedně bez ohledu na předpony di- a tri-. | null | che_0830 | concept | cs | Jak se řadí substituenty? | [
"Abecední pořadí.",
"Di- a tri- se ignorují.",
"Příklad: ethyl před methyl."
] | chemistry | Answer: Abecedně.
Steps:
1. Abecední pořadí.
2. Di- a tri- se ignorují.
3. Příklad: ethyl před methyl. | organic_naming |
The di- prefix counts two identical substituents. | {
"A": "Two methyls",
"B": "Two chains",
"C": "Two bonds",
"D": "Two rings"
} | che_0831 | multiple_choice | en | What does dimethyl mean? | [
"Di- means two.",
"Two methyl groups.",
"Select option A."
] | chemistry | Answer: Two methyls.
Steps:
1. Di- means two.
2. Two methyl groups.
3. Select option A.
Answer: (A) | organic_naming |
The name is 2-methylpentane: five carbons with a methyl on carbon 2. | null | che_0832 | worked_example | en | Name (CH3)2CHCH2CH2CH3. | [
"Longest chain: 5 = pentane.",
"Methyl on carbon 2.",
"Name: 2-methylpentane."
] | chemistry | Answer: 2-methylpentane.
Steps:
1. Longest chain: 5 = pentane.
2. Methyl on carbon 2.
3. Name: 2-methylpentane. | organic_naming |
The parent chain is the longest one, preferring most substituents on ties. | null | che_0833 | concept | en | How is the parent chain chosen? | [
"Find longest chain.",
"Tie-break: most branches.",
"It sets the root name."
] | chemistry | Answer: Longest with most branches.
Steps:
1. Find longest chain.
2. Tie-break: most branches.
3. It sets the root name. | organic_naming |
The name is chloroethene: chlorine on a two-carbon double bond. | null | che_0834 | worked_example | en | Name CH2=CHCl. | [
"Count 2 carbons, double bond.",
"Chlorine substituent.",
"Name: chloroethene."
] | chemistry | Answer: Chloroethene.
Steps:
1. Count 2 carbons, double bond.
2. Chlorine substituent.
3. Name: chloroethene. | organic_naming |
Chloroethene is commonly called vinyl chloride. | {
"A": "Ethylene",
"B": "Acetylene",
"C": "Vinyl chloride",
"D": "Styrene"
} | che_0835 | multiple_choice | en | What is the common name of CH2=CHCl? | [
"Vinyl group plus chloride.",
"Standard trivial name.",
"Select option C."
] | chemistry | Answer: Vinyl chloride.
Steps:
1. Vinyl group plus chloride.
2. Standard trivial name.
3. Select option C.
Answer: (C) | organic_naming |
C3H8 je propan. | null | che_0836 | worked_example | cs | Pojmenuj sloučeninu C3H8. | [
"Tři uhlíky.",
"Jen jednoduché vazby.",
"Název: propan."
] | chemistry | Answer: Propan.
Steps:
1. Tři uhlíky.
2. Jen jednoduché vazby.
3. Název: propan. | organic_naming |
Dienes have two double bonds and use the -diene suffix with locants. | null | che_0837 | concept | en | How are dienes named? | [
"Find both double bonds.",
"Number lowest set.",
"Suffix -diene with locants."
] | chemistry | Answer: Locants plus -diene.
Steps:
1. Find both double bonds.
2. Number lowest set.
3. Suffix -diene with locants. | organic_naming |
Two double bonds use the -diene suffix. | {
"A": "-ene",
"B": "-diene",
"C": "-yne",
"D": "-ane"
} | che_0838 | multiple_choice | en | What suffix marks two double bonds? | [
"One gives -ene.",
"Two give -diene.",
"Select option B."
] | chemistry | Answer: -diene.
Steps:
1. One gives -ene.
2. Two give -diene.
3. Select option B.
Answer: (B) | organic_naming |
The name is buta-1,3-diene: double bonds at carbons 1 and 3. | null | che_0839 | worked_example | en | Name CH2=CHCH=CH2. | [
"Count 4 carbons.",
"Bonds at 1 and 3.",
"Name: buta-1,3-diene."
] | chemistry | Answer: Buta-1,3-diene.
Steps:
1. Count 4 carbons.
2. Bonds at 1 and 3.
3. Name: buta-1,3-diene. | organic_naming |
Phenyl attaches the ring directly while benzyl adds a CH2 spacer. | null | che_0840 | concept | en | How do phenyl and benzyl differ? | [
"Phenyl is C6H5-.",
"Benzyl is C6H5CH2-.",
"Spacer changes reactivity."
] | chemistry | Answer: Direct versus CH2 spacer.
Steps:
1. Phenyl is C6H5-.
2. Benzyl is C6H5CH2-.
3. Spacer changes reactivity. | organic_naming |
Benzyl je skupina C6H5CH2- s methylenovým můstkem. | null | che_0841 | concept | cs | Co je benzyl? | [
"Fenyl plus CH2.",
"Vzorec C6H5CH2-.",
"Příklad: benzylchlorid."
] | chemistry | Answer: Skupina C6H5CH2-.
Steps:
1. Fenyl plus CH2.
2. Vzorec C6H5CH2-.
3. Příklad: benzylchlorid. | organic_naming |
The C6H5CH2- fragment is called benzyl. | {
"A": "Phenyl",
"B": "Benzyl",
"C": "Tolyl",
"D": "Styryl"
} | che_0842 | multiple_choice | en | What is the C6H5CH2- group called? | [
"Ring plus CH2 spacer.",
"Named benzyl.",
"Select option B."
] | chemistry | Answer: Benzyl.
Steps:
1. Ring plus CH2 spacer.
2. Named benzyl.
3. Select option B.
Answer: (B) | organic_naming |
The name is pentanoic acid: five carbons ending in -COOH. | null | che_0843 | worked_example | en | Name CH3CH2CH2CH2COOH. | [
"Count 5 carbons.",
"-COOH gives -oic acid.",
"Name: pentanoic acid."
] | chemistry | Answer: Pentanoic acid.
Steps:
1. Count 5 carbons.
2. -COOH gives -oic acid.
3. Name: pentanoic acid. | organic_naming |
CH4 je methan. | null | che_0844 | worked_example | cs | Pojmenuj sloučeninu CH4. | [
"Jeden uhlík.",
"Jen jednoduché vazby.",
"Název: methan."
] | chemistry | Answer: Methan.
Steps:
1. Jeden uhlík.
2. Jen jednoduché vazby.
3. Název: methan. | organic_naming |
Esterification joins a carboxylic acid and an alcohol, releasing water. | null | che_0845 | concept | en | How do esters form? | [
"Acid plus alcohol.",
"Water splits out.",
"Acid catalyst helps."
] | chemistry | Answer: Acid plus alcohol minus water.
Steps:
1. Acid plus alcohol.
2. Water splits out.
3. Acid catalyst helps. | organic_naming |
Planar carbocations are attacked from both faces, giving a racemic mix. | null | che_0846 | concept | en | Why does SN1 give racemic products? | [
"Carbocation is flat.",
"Attack from either face.",
"Both enantiomers form."
] | chemistry | Answer: Flat ion, both faces.
Steps:
1. Carbocation is flat.
2. Attack from either face.
3. Both enantiomers form. | organic_mechanisms |
SN1 attack from both faces yields a racemic mixture. | {
"A": "Inversion",
"B": "Racemic",
"C": "Retention",
"D": "None"
} | che_0847 | multiple_choice | en | What stereochemistry results from SN1? | [
"Planar intermediate.",
"Both faces attacked.",
"Select option B."
] | chemistry | Answer: Racemic.
Steps:
1. Planar intermediate.
2. Both faces attacked.
3. Select option B.
Answer: (B) | organic_mechanisms |
The SN2 rate stays the same because 2 x 0.5 equals 1. | null | che_0848 | worked_example | en | SN2 rate = k[RX][Nu]. [RX] doubles and [Nu] halves. What happens? | [
"Write: rate = k x 2[RX] x 0.5[Nu].",
"Factor: 1 x k[RX][Nu].",
"Rate unchanged."
] | chemistry | Answer: Unchanged.
Steps:
1. Write: rate = k x 2[RX] x 0.5[Nu].
2. Factor: 1 x k[RX][Nu].
3. Rate unchanged. | organic_mechanisms |
Racemizace je vznik směsi obou enantiomerů 1:1. | null | che_0849 | concept | cs | Co je racemizace? | [
"Planární meziprodukt.",
"Atak z obou stran.",
"Směs 1:1 bez otáčivosti."
] | chemistry | Answer: Směs enantiomerů 1:1.
Steps:
1. Planární meziprodukt.
2. Atak z obou stran.
3. Směs 1:1 bez otáčivosti. | organic_mechanisms |
E1 first loses the leaving group, then a base removes a proton. | null | che_0850 | concept | en | What are the E1 mechanism steps? | [
"Leaving group departs.",
"Carbocation forms.",
"Base removes H+."
] | chemistry | Answer: Ionize, then deprotonate.
Steps:
1. Leaving group departs.
2. Carbocation forms.
3. Base removes H+. | organic_mechanisms |
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