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Question: <p>I was wondering how to answer a question I got from my students about the possible recovery of gold from solution. We just finished the reaction between silver ions and copper metal and they wondered why copper wouldn't displace gold from solution in an electrochemical reaction. The redox potentials sugge... | https://chemistry.stackexchange.com/questions/145552/electrochemistry-gold-recovery |
Question: <p>Unfortunately, I don't have batteries to waste to test this myself, but I am curious... </p>
<p>Let's say you have two identical batteries. AA Duracell.</p>
<p>Now let's say you run one of the batteries through an LED until the LED starts emitting at half the intensity it was emitting at when you first s... | https://chemistry.stackexchange.com/questions/883/can-i-use-one-alkaline-battery-to-recharge-another |
Question: <p>I recently conducted an experiment where I electrolyzed a solution of sodium chloride. I was using a copper coin as the anode, and I observed a pale blue precipitate in the cup when I was done with the experiment. I then deduced the following:</p>
<p>The chloride ions get oxidized at the anode: </p>
<p>$... | https://chemistry.stackexchange.com/questions/4803/electrolysis-water-to-hydrogen-gas |
Question: <p>I've got the following from a <a href="http://megglobal.com/commitment.html" rel="nofollow noreferrer">supposed new energy-storage technologist</a>. It's supposed to be a fancy new cheap, high-powered, highly scalable battery. I want to know if this is known chemistry, and if there's anything genuinely rev... | https://chemistry.stackexchange.com/questions/5109/is-there-anything-in-the-literature-that-supports-revolutionary-claims-for-this |
Question: <p>I have been watching some videos on how batteries work and they seem to talk about the cathode being the most important. I also watched another video a long time ago and while my memory is blurred it talked about impurities in the cathode being the only reason the electrical charge doesn't flow constantly.... | https://chemistry.stackexchange.com/questions/5446/in-a-battery-what-would-happen-if-you-had-a-perfectly-uniform-and-pure-cathode |
Question: <p>I am trying to make a copper sulfate electroplating solution. I came across a <a href="http://www2.bren.ucsb.edu/~dturney/port/papers/Modern%20Electroplating/02.pdf" rel="nofollow">document</a> (Schlesinger and Paunovic 2011) which mentions the amount of copper sulfate that should be added to water to crea... | https://chemistry.stackexchange.com/questions/6072/what-are-high-throw-solutions |
Question: <p>Take the electrolysis of Lead(II) bromide:</p>
<p>We can write it as two half-reactions:</p>
<p>$$\ce{Pb^{2+}(l) + 2e^{-} \rightarrow Pb(l)}$$</p>
<p>$$\ce{Br^{-} \rightarrow Br + e^{-}}$$</p>
<p>In the electrolysis reaction, lead is formed at the cathode and bromine is liberated at the anode. But why ... | https://chemistry.stackexchange.com/questions/6773/during-electrolysis-why-are-the-products-attracted-to-the-cathode |
Question: <p>A current of 2.25 A is applied to $\ce{NiCl2}$ solution</p>
<p>A. Write the balanced half reaction that takes place at the anode
B. Write the balanced half reaction that takes place at the cathode</p>
<p>Can someone check if my answers seem logical? I'm not quite sure if I did the problem correctly</p>
... | https://chemistry.stackexchange.com/questions/7726/balanced-reactions-at-the-anode-and-cathode |
Question: <p>The reduction of water at a cathode is represented by the following equation:</p>
<p>Cathode (reduction): $\ce{2 H2O_{(l)} + 2e^{−} → H2_{(g)} + 2 OH^{-}_{(aq)}}$</p>
<p>If this is done in a divided cell, what would happen to the $\ce{OH-}$ anions? The hydrogen gas would accumulate and bubble would form.... | https://chemistry.stackexchange.com/questions/8180/what-happens-to-the-hydroxide-anion-during-the-electroreduction-of-water |
Question: <p>I have a pot with some (bottled) water and added (sea) salt. It has a pencil (graphite) and tin foil (aluminum). The pencil is connected to the positive outlet of a solar panel and the tinfoil is connected to the negative outlet of the solar panel (effectively 'charging' the electrolytic cell).</p>
<p>To ... | https://chemistry.stackexchange.com/questions/9206/electrolytic-cell-chemical-composition-during-after-charging |
Question: <p>With the following setup: plastic container, water (impure), pencil (anode), tin foil (aluminum, cathode) and solar panels supplying electrical charge (roughly 36v at about 400-800ma), with the intention of producing lye via electrochemistry:</p>
<p>1) Would it be possible to produce the right kind of lye... | https://chemistry.stackexchange.com/questions/9214/electrochemistry-lye-quality |
Question: <p>I am doing a lab for school and I do not know what this question is asking. In this lab we are making electrochemical cells from different metals. </p>
Answer: <p>You have a standard pot of liquid electrolyte into which are dipped non-touching same-spaced paired strips of different clean metals. The exte... | https://chemistry.stackexchange.com/questions/9855/how-to-determine-the-relative-differences-in-activity-between-metals |
Question: <p>Why more attractive metals will be oxidized? Aren't they being reduced, because they attract and receive electrons from negative polyatomic ions? So they will be anodes, where oxidization occurs. Why anodes are negative in voltaic cells and positive in electrolytic cells? Same for cathodes.</p>
Answer: <p... | https://chemistry.stackexchange.com/questions/10203/voltaic-and-electrolytic-cells |
Question: <p>And how do I find the diffusion coefficient from a Levich plot?</p>
Answer: <p>I would recommend you take a look at the book Electrochemical Methods fundamentals and applications.</p>
<p>For the Koutecý-Levich equation (totally irreversible one-step, one-electron reaction):</p>
<p>$\Large \frac{1}{i}=\f... | https://chemistry.stackexchange.com/questions/10686/how-does-the-diffusion-coefficient-of-a-species-affect-the-limiting-current-for |
Question: <p>I know that the limiting current is proportional to the square root of the rotation speed, but what does the slope of the plot represent?</p>
Answer: <p>if you mean the following plot:
<img src="https://i.sstatic.net/zGGBU.jpg" alt="enter image description here"></p>
<p>(Electrochemical Methods. fundamen... | https://chemistry.stackexchange.com/questions/10688/what-does-the-slope-of-a-levich-plot-represent |
Question: <p>Is there any difference between the terms specific conductivity and conductance. If yes, please explain.</p>
Answer: <p>Let's take a wire inside cable for example. That wire's <strong>conductance</strong> is just the inverse of the resistance this cable is making when electricity passes through it. This d... | https://chemistry.stackexchange.com/questions/10949/confusion-regarding-specific-conductivity |
Question: <p>The electronic conductance of a metal depends on its density.Does this mean that if we increase the density of the metal,its electronic conductance will increase?How does it happen?</p>
Answer: <p>You cannot change the density of a metal without also changing other properties. </p>
<p>Brass is a mixture ... | https://chemistry.stackexchange.com/questions/13606/how-does-electronic-conductance-of-a-metal-change-with-density |
Question: <p>I'm doing Grade 12 Chemistry and I'm unsure of this, taking the hydrogen electorde as having a potential of 0 volts.</p>
<p>I'll use the copper-zinc cell as an example. Just let me know if I've got the full logic right:</p>
<ol>
<li><p>Zinc has higher electronegativity, so due to the equilibrium $\ce{Zn ... | https://chemistry.stackexchange.com/questions/15002/in-a-galvanic-cell-why-does-an-electrode-with-a-higher-potential-pull-the-ele |
Question: <p>I found that reaction: HNO3 + 4.1633363423443E-17 H3O = NO2{+} + OH{-}
Please help me understand " 4.1633363423443E-17" term.</p>
Answer: <p>It seems to me like you were asked to balance a chemical equation and you used some computer program to do it for you instead.</p>
<p>4.1633363423443E-17 is the res... | https://chemistry.stackexchange.com/questions/15760/protonation-of-nitric-acid |
Question: <p>I was carrying out an experiment into the effect of temperature changes on the standard potential of a cell. </p>
<p>$$\ce{Zn(s) +2Fe^{3+}->Zn^{2+} +2Fe^{2+}}$$
I used equi-molar concentrations of $\ce{Fe(CN)_6^{4-}}$and $\ce{Fe(CN)_6^{3-}}$. Thus the Nernst equation</p>
<p>$$\mathrm{E^{\theta}_{cell}... | https://chemistry.stackexchange.com/questions/16929/electrochemical-potentials |
Question: <p>During the electrolysis of $\ce{H2SO4}$, $\ce {OH-}$ ions are more reactive than $\ce {SO4^{2-} }$ ions and so they dissociate. as $\ce {OH-}$ ions dissociate, they are the negative ions that carry current. So when the concentration of $\ce {H2SO4}$ is increased, the concentration of $\ce {OH-}$ ions actua... | https://chemistry.stackexchange.com/questions/23495/in-the-electrolysis-of-h%e2%82%82so%e2%82%84-solution-when-the-concentration-is-increased-why-d |
Question: <p>Since in rusting (oxidation) of Iron, transfer of 4 electrons takes place is it possible to use this reaction under catalytic conditions to create a simple electric cell, even if it just gave a millivolt of potential.</p>
<p>$\ce {Fe + H2O -> FeOH3 + H2}$</p>
<p>Considering that we have complete contr... | https://chemistry.stackexchange.com/questions/23720/can-we-make-a-rusting-battery |
Question: <p>as far as I've understood to measure the decomposition potential of an electrolyte using a galvanic cell we just put two electrodes, connect them to a battery, and vary the external potential till when we observe a current. The potential at which the current starts to grow linearly is the decomposition pot... | https://chemistry.stackexchange.com/questions/24188/offset-in-measuring-decomposition-potentials |
Question: <p>I've been planning an experiment on how to make galvanic cells and during my research I came across an article in which chloridric acid was used, along with a soluble salt and agar-agar, in salt bridges.
Since then, I've been wondering why chloridric acid was added to agar-agar.</p>
<p>Thanks in advence... | https://chemistry.stackexchange.com/questions/25010/why-is-chloridric-acid-used-in-salt-bridges |
Question: <p>Streaming potential is an electrochemical phenomenon that a that relates
electric currents with the relative movement of solid and liquid phases in contact with
each other.</p>
<p>So when a liquid moves past a solid a potential is generated. The equations for the values of the potential and current genera... | https://chemistry.stackexchange.com/questions/26284/an-electric-potential-is-generated-when-a-liquid-moves-with-respect-to-a-solid |
Question: <p><a href="http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1548283&tag=1" rel="nofollow">This paper</a> describes the measurement of streaming potential using a potential divider configuration. However it is unclear where the potential difference is created. From the diagram it appears that it is cre... | https://chemistry.stackexchange.com/questions/26287/how-is-streaming-potential-measured |
Question: <p>I want to convert resultant hours of salt spray corrosion test to estimated values in years for real life environments such as marine. In other words, How could I predict the result of real life tests using salt spray data?</p>
Answer: <p><em>Note that I'm not an expert in this field and wikipedia itself ... | https://chemistry.stackexchange.com/questions/26452/how-to-use-salt-spray-data-in-real-environments |
Question: <p>This is the question extracted from my country high school level' exam.
So it asks to discuss the feasibility of the electrochemical cell to carry out electrolysis of an aqueous solution of sodium chloride at standard condition.</p>
<p>Al(s)/Al(aq)//Cu(aq)/Cu</p>
<p>My question is how I should start to ... | https://chemistry.stackexchange.com/questions/27035/the-feasibility-of-the-electrochemical-cell |
Question: <p>Following <a href="https://byo.com/stories/issue/item/3113-etch-your-kettle-projects" rel="nofollow">this plan</a>, I am wondering what the byproducts of this method are? At the site with the q-tip, the solution turned a bright yellow, with the q-tip turning a dark yellow, almost red. Holding the q-tip in ... | https://chemistry.stackexchange.com/questions/27126/reverse-electro-plating-byproducts |
Question: <p>According to the Nernst equation, the electrode potential $E$ is
$$E = E^\circ - \frac{RT}{nF}\ln\frac{[\ce{M}]}{[\ce{M^{$n$+}}]}$$</p>
<p>Question is, why? Assuming a simple galvanic cell, we know that in general if the temperature is increased, there should be more collisions of the solution with the el... | https://chemistry.stackexchange.com/questions/28036/why-does-an-increase-in-temperature-decrease-the-electrode-potential |
Question: <p>When recharging a lead-acid battery, how are the terminals of the battery connected to the voltage source. I mean, do we connect the positive terminal of the battery to the negative terminal of the source and vice versa? Or does the positive go with the positive and the negative with the negative? Also, ar... | https://chemistry.stackexchange.com/questions/28634/how-is-a-car-battery-recharged |
Question: <p>Two questions: </p>
<p>First, how does the gate provide a positive charge by running a current through it? I really just don't see how this positive charge could be achieved, unless you had some sort of battery in the gate itself and attached a wire to donate some of the electrons flowing through to the c... | https://chemistry.stackexchange.com/questions/28820/transistors-how-does-the-gate-work |
Question: <p>The equation: </p>
<p>$$E^{。}_{cell}= \frac{RT}{nF}\ln K_{eq}$$</p>
<p>We all know cell potential is intensive, not affected by the amount, Because: $volt=\frac{joule}{coulomb}$. Both joule and coulomb will be doubled altogether.</p>
<p>But as seen from the equation, cell potential is affected by the nu... | https://chemistry.stackexchange.com/questions/28954/does-the-relationship-equation-between-standard-cell-potential-and-equilibrium-c |
Question: <p>I mean by "combining" is to make a new half-reaction equation and not an overall equation for a reaction in whole.</p>
<p>For instance, I was trying to arrive at the following half-reaction:</p>
<p>$\ce{MnO2(s) + 4H+(aq) + 2e- -> Mn^{2+}(aq) + 2H2O(l)}\quad E^\circ= 1.23\,\mathrm{V}$</p>
<p>by combin... | https://chemistry.stackexchange.com/questions/28995/why-can-some-redox-half-reactions-be-combined-and-some-cannot |
Question: <p>The classic voltaic cell has a <span class="math-container">$\ce{Zn}$</span> anode and <span class="math-container">$\ce{Cu}$</span> cathode. The reduction half reaction occurring at the cathode combines aqueous copper ions and electrons supplied by the anode to form solid <span class="math-container">$\ce... | https://chemistry.stackexchange.com/questions/28732/why-does-the-cathode-have-to-be-made-out-cu-in-a-zn-cu-voltaic-cell |
Question: <h2>Question</h2>
<p>Suppose you have a cell set up between a copper metal/copper(II) ion electrode and a reference electrode.</p>
<p>Under standard conditions, the emf of this cell was −0.07 V. The standard electrode potential of the copper metal / copper(II) ion electrode is +0.34 V. Hence the standard el... | https://chemistry.stackexchange.com/questions/31921/what-is-the-meaning-of-signs-in-electrode-potentials |
Question: <p>I won this <a href="http://rads.stackoverflow.com/amzn/click/B007V5TEMW">"toy"</a> at a science fair...
Now I have to make a short presentation about it in school.
On the package description they describe its energy source as "fuel cell"...
It consists out of a metal plate(magnesium), a black metal plate ... | https://chemistry.stackexchange.com/questions/32907/is-this-product-description-wrong-and-a-simple-battery-and-not-a-fuel-cell |
Question: <p>Does flipping a reaction as written change the sign of the value of E or is it a completely different value? </p>
<p>For example if I have the value for the half reaction $\ce{Cl2 + 2e- -> 2Cl-}$ but need the value for the opposite reaction ($\ce{2Cl- -> Cl2 + 2e-}$), do I just put a negative sign a... | https://chemistry.stackexchange.com/questions/34268/electrode-potential-half-reactions |
Question: <blockquote>
<p>What are the products of an alkane and a perchlorate reaction?</p>
<p>e.g., making the alkane methane and the perchlorate anhydrous for simplicity:</p>
</blockquote>
<p><strong>My effort</strong>:</p>
<p><span class="math-container">$$\ce{Mg(ClO4)2 + 4CH4 -> MgCl2 + 4CO2}$$</span></p>
<p>le... | https://chemistry.stackexchange.com/questions/44119/stoichiometry-of-alkane-perchlorate-reaction |
Question: <p>Does "Mole of Iodine" or any other element that normally appears as diatomic molecules refer to a mole of single atoms (<span class="math-container">$6.02\times 10^{23}$</span> iodine atoms) or a mole of the molecules (<span class="math-container">$6.02\times 10^{23}$</span> molecules of <span cl... | https://chemistry.stackexchange.com/questions/53609/moles-of-diatomic-molecules |
Question: <blockquote>
<p>Which of the following samples contains the largest number of atoms?</p>
<p>a. 2.0 moles of <span class="math-container">$\ce{H3PO4}$</span><br />
b. 3.0 moles of <span class="math-container">$\ce{H2SO3}$</span><br />
c. 4.0 moles of <span class="math-container">$\ce{HNO3}$</span><br ... | https://chemistry.stackexchange.com/questions/59761/which-of-the-following-samples-contains-the-largest-number-of-atoms |
Question: <p>10 g of Mg(NO3)2 was dissolved in 120 g of water. The result is a solution with a
density of 1.12 g / ml. Determine the percentage concentration
(in %) and the molar concentration (in mol/L) of the resulting
solution</p>
Answer: <p>As you are new to this forum I want to welcome you but nevertheless I woul... | https://chemistry.stackexchange.com/questions/135405/stoichiometry-and-percentage-concentration |
Question: <p>Why are figures removed from the calculation for values that are known in more detail? E.g. if you want to calculate the number of moles in 75.0 g H2 molecules. Why should one here use
for the relative atomic mass/molar mass of H 1,008 u or g/mol instead of 1,0079 u or g/mol?
What is the purpose of this?
I... | https://chemistry.stackexchange.com/questions/136321/why-use-1-008-g-mol-instead-of-1-0079-g-mol-calculating-the-number-of-moles-in-7 |
Question: <blockquote>
<p>Tin(IV) iodide is prepared by direct combination of the elements.
Add 2.00 g of granulated tin to a solution of 6.35 g of iodine. Write an equation for this reaction.</p>
</blockquote>
<p>Attempt:</p>
<p><strong>1.</strong> Determine the amount of tin using <strong>moles = mass/molar mass</str... | https://chemistry.stackexchange.com/questions/35309/equation-for-reaction-of-tin-and-iodine-to-produce-tiniv-iodide |
Question: <p>What is the liquid which has the most hydrogen atoms per volume at STP ?
Is there anything better than water?</p>
<p><a href="https://chemistry.stackexchange.com/questions/117073/most-dense-hydrogen-containing-composition">This answer</a> does not answer this question because none of the compounds listed i... | https://chemistry.stackexchange.com/questions/138783/what-is-the-liquid-which-has-the-most-hydrogen-atoms-per-volume |
Question: <p>I calculated this:
molar mass (M) of Mg(NO3)2 is 148,32 (24,3 + 2<em>14,01 + 6</em>16)
so when there is 7 grams Mg(NO3)2 there is 0,0472 mol (7/148,32)</p>
<p>But how do i find out how much of that is oxygen? Do i just divide by 8 and multiply by 6? (because 8 atoms of with 6 are oxygen)</p>
Answer: <p>No... | https://chemistry.stackexchange.com/questions/141359/how-much-grams-oxygen-is-in-7-gram-magnesiumnitrate-mgno32 |
Question: <p>The problem is:</p>
<blockquote>
<p>A quantity of <span class="math-container">$\pu{35.2 g}$</span> if a certain hydrocarbon gas, occupies <span class="math-container">$\pu{13.2 L}$</span>, measured at <span class="math-container">$\pu{1 atm}$</span> and at <span class="math-container">$\pu{323 K}$</span>.... | https://chemistry.stackexchange.com/questions/143757/find-the-molecular-formula-of-a-gas |
Question: <p>How does the balanced reaction look for these compounds? I found that phosphoric acid instead of hydrogen phosphate creates a much easier problem, but the teacher said hydrogen phosphate and I can't seem to balance it.</p>
Answer: <p>Most likely that your teacher meant to say phosphoric acid ($\ce{H3PO4}$... | https://chemistry.stackexchange.com/questions/5018/calcium-carbonate-and-hydrogen-phosphate-producing-calcium-phosphate-carbon-dio |
Question: <p>My book gives me the following problem:
"A mixture of $125.0 g$ $\ce{N2}$ and $32.0 g$ $\ce{H2}$ reacts to $36.5 g$ $\ce{NH3}$. Calculate the efficiency."</p>
<p>My method to do this is - one I learned from my teacher, to put every given molecule's amount of substance (moles) in a table with 3 steps: star... | https://chemistry.stackexchange.com/questions/6640/stoichiometry-efficiency |
Question: <p>If $15.0\ \mathrm{mol}$ of nitrogen are reacted with $30.0\ \mathrm{mol}$ of hydrogen, how much ammonia will be produced?</p>
<p>$$\ce{N2 + 3H2 -> 2NH3}$$</p>
<p>What I’ve tried is the following: </p>
<p>$$\dfrac{n(\ce{N2})}{n(\ce{H2})}=\dfrac{1}{3}=\dfrac{15.0\ \mathrm{mol}}{x}$$</p>
<p>$$\dfrac{n(... | https://chemistry.stackexchange.com/questions/6716/amount-of-substance-produced-in-chemical-reaction |
Question: <p>$$C_x H_y O_z$$ </p>
<p>1.What are the units of x,y,z.I've read that they're termed as 'stoichiometric coefficients'.</p>
<p>2.What is the unit of mass proportion of carbon(c) in the fuel?</p>
<p>$$c=\frac{M_{carbon}}{M_{fuel}} .x$$</p>
Answer: <p>The stoichiometric coefficients is something else than ... | https://chemistry.stackexchange.com/questions/7727/units-in-stoichiometry |
Question: <blockquote>
<p>There are two gases in a container: krypton and carbon dioxide. If the mass of the gases is 35 grams, and total pressure of the container is 0.708 atm, and the pressure of krypton is 0.250 atm. What is the mass of the krypton?</p>
</blockquote>
<p>I've found the mole fraction of krypton is ... | https://chemistry.stackexchange.com/questions/7899/calculating-mass-of-krypton-from-mole-fraction |
Question: <p>I'm doing revision questions and want to double check something. The opening information reads: </p>
<blockquote>
<p>Two chlorides of iron were prepared. One was prepared by reacting iron with dry chlorine
gas. 4.50 g of iron reacted with chlorine gas to produce 13.01 g of the chloride.
The other ch... | https://chemistry.stackexchange.com/questions/9958/laws-of-chemical-combination |
Question: <p>I need to write balanced equations describing the following reactions:</p>
<ul>
<li>one mole of $\ce{Al2Me6}$ with two moles of water</li>
<li>excess of $\ce{Al2Me6}$ with silicon dioxide</li>
<li>excess of $\ce{Al2Me6}$ with tin(IV) chloride</li>
</ul>
<p>My answer so far:</p>
<ul>
<li>a) $\ce{2H2O + A... | https://chemistry.stackexchange.com/questions/10135/reactions-involving-trimethylaluminium-al2me6 |
Question: <p>here is a question that i don't know how it is solved :</p>
<p>A sample that is 75 % chloride by mass is dissolved in water and treated with an excess of AgNO3. If the mass of the AgCl precipitate that forms is 2.013 g, what was the mass of the original sample?</p>
<p>I hope you give me the the proper wa... | https://chemistry.stackexchange.com/questions/13751/whats-the-mass-of-the-original-sample-g |
Question: <p>the question says :</p>
<p>Two elements, A and B, combine to form two binary compounds. In the first
compound, 3.5 g of A combines with 8.00 g of B. In the second compound,
5.0 g of A combines with 17.1 g of B. If the formula of the first compound is
AB2, then the formula of the second compound would be ?... | https://chemistry.stackexchange.com/questions/13752/use-the-given-information-to-write-the-formula-of-this-compound |
Question: <p>A sample of copper(II) sulfate pentahydrate (CuSO4·5H2O) contains 0.360 g of water.
What is the total number of atoms in the compound</p>
<p>what's the idea of this question?</p>
<p>what i know is that atoms number is found by multiplying the Avogadro number by the mol's number</p>
<p>??</p>
Answer: <p... | https://chemistry.stackexchange.com/questions/13769/a-sample-of-copperii-sulfate-pentahydrate-cuso4-5h2o-contains-0-360-g-of-wat |
Question: <blockquote>
<p>A simple mixture of $\ce{NaCl}$ and $\ce{NaBr}$ weighing $0.180~ \mathrm{g}$ is treated with $\ce{AgNO3}$ solution to give $0.3715~ \mathrm{g}$ of precipitate. Calculate the content of $\ce{NaCl}$ and $\ce{NaBr}$ in the mixture.</p>
</blockquote>
<p>The answer given in book are $\ce{NaCl}$ ... | https://chemistry.stackexchange.com/questions/18756/given-the-mass-of-precipitate-how-can-i-calculate-the-relative-amount-of-the-or |
Question: <blockquote>
<p><strong>Question</strong><br>
If a metallic oxide has $40\,\%$ oxygen, find the equivalent weight of
the metal.</p>
</blockquote>
<p>This amounts to finding the atomic weight of the metal and the charge on the cation (in effect identifying the metal itself). </p>
<p>I didn't know how t... | https://chemistry.stackexchange.com/questions/18939/what-does-a-metallic-oxide-has-40-oxygen-mean |
Question: <p>If 2.30 mol of sodium reacts with 1.95 mol of water, how many moles of sodium hydroxide are produced? </p>
<p>Would it be 2.3 mol NaOH?</p>
Answer: <p>The first step is to figure out a reaction equation.</p>
<p>[I'm assuming elemental] sodium reacts with water violently because it releases a lot of ener... | https://chemistry.stackexchange.com/questions/19555/limiting-reactant-and-percent-yield |
Question: <p>As part of a pre-lab exercise in Chemistry, we went through the necessary calculations to identify an unknown metal in a metal carbonate. The method was gas evolution by means of hydrochloric acid (see equation below). </p>
<p><span class="math-container">$$\ce{HCl + M2CO3 -> MCl + CO2 + H2O}$$</span><... | https://chemistry.stackexchange.com/questions/24246/how-to-find-the-molar-mass-of-an-unknown-metal-carbonate-through-a-gas-evolution |
Question: <p>What mass of precipitate forms when a solution containing 6.24 g of potassium sulfide is reacted with a solution containing 19.2 g of barium nitrate?</p>
<p>I have already identified the limiting reagent $\left(\text{K}_2 \text{S}\right)$ as well as the mass of the precipitate.</p>
<p>My question, howeve... | https://chemistry.stackexchange.com/questions/24656/limiting-reagent-stoichiometry |
Question: <blockquote>
<p>One gram of Hydrogen reacts with exactly (almost) 8 grams of oxygen to produce $\ce{H2O}$. Another single gram of Hydrogen reacts with 16 grams of Oxygen to produce $\ce{H2O2}$. </p>
</blockquote>
<p>Can the ratio $\frac{m_O}{m_H}$ be determined from this information? If not, what else do c... | https://chemistry.stackexchange.com/questions/25027/atomic-mass-ratios-is-the-problem-providing-enough-info |
Question: <p>A student mixed 260ml of 1.2 M lead(II) nitrate with 300ml of 1.90M potassium iodide. What is the final concentration of $\ce{NO3^{-}}$ ?</p>
<p>the answer is 1.11M , but he used the moles of lead(II) nitrate to find out the moles of $\ce{NO3^{-}}$ ,, and I think he should had used the moles of potassium ... | https://chemistry.stackexchange.com/questions/26726/calculate-the-final-concentration-of-this-equation |
Question: <p>A question says:</p>
<p>Find the empirical formula of an organic compound from the following composition:</p>
<p>34.62% C, 3.88% H, 61.50% O.</p>
<p>The answer is $\ce{C3H4O4}$.
It was found by using the mass (percentages) divided by the molar mass of each element.</p>
<p>But they didn't consider the (... | https://chemistry.stackexchange.com/questions/26848/why-not-to-consider-hydrogen-and-oxygen-moles-to-determine-an-empirical-formula |
Question: <p>A student analysed a hydrocarbon X and found it to be containing 43g carbon and 7.2g hydrogen.The relative molecular mass of X was found to be 42.What is the molecular formula of X?</p>
Answer: <p>$43\ \mathrm g$ of carbon for $7.2\ \mathrm g$ hydrogen.<br>
Molar mass of carbon is $12\ \mathrm{g/mol}$ and... | https://chemistry.stackexchange.com/questions/27046/the-molecular-formula-of-an-unknown-hydrocarbon |
Question: <p>I was once told on this site that it was incorrect form to use units that specify the chemical being referred to in dimensional analysis. For example: </p>
<p>$$150.~\mathrm{g}~~\ce{KNO3} \cdot \frac{1~\mathrm{mol}~~\ce{KNO3}}{101.103~\mathrm{g}~~\ce{KNO3}} \cdot{} \frac{1~\mathrm{mol}~~\ce{C7H4O}}{6~\mat... | https://chemistry.stackexchange.com/questions/29711/dimensional-analysis-in-chemistry |
Question: <blockquote>
<p>What is the amount of nitrate ions in <span class="math-container">$20.0\:\mathrm{g}$</span> of <span class="math-container">$\ce{Fe(NO3)3}$</span>?</p>
</blockquote>
<p>The chemical formula for the nitrate ion is <span class="math-container">$\ce{NO3}$</span>, I think.</p>
<p>The molar ma... | https://chemistry.stackexchange.com/questions/33040/what-is-the-amount-of-nitrate-ions-in-20-g-of-feno33 |
Question: <p>The mass of one molecule of a compound is $2.19\times10^{-22}\ \mathrm g$. What is the molar mass of the compound?</p>
<p>My attempt:
Using the formula <strong>moles=mass/molar mass</strong>, I found how to calculate molar mass using the formula <strong>molar mass=moles/mass</strong>.
Therefore, I was und... | https://chemistry.stackexchange.com/questions/35257/calculate-molar-mass-of-a-compound-from-a-given-molecular-mass |
Question: <p>I will calculate the change in enthalpy of combustion of 1.12g of hexane.</p>
<p><strong>1)</strong> Calculate the energy transferred to 200g of water using the equation: <em>J = mass of water in grams (<strong>200g</strong>) x specific heat capacity of water (<strong>4.18 J/gK</strong>) x temperature inc... | https://chemistry.stackexchange.com/questions/36923/calculating-change-in-enthalpy-of-combustion-of-1-12g-of-hexane |
Question: <blockquote>
<p>A <span class="math-container">$\pu{4.250 g}$</span> sample of <span class="math-container">$\ce{Na2SO4.nH2O}$</span> the sample loses <span class="math-container">$\pu{2.388 g}$</span> upon heating. What is <span class="math-container">$n$</span> for this hydrate?</p>
</blockquote>
<p>Do I... | https://chemistry.stackexchange.com/questions/37592/how-to-calculate-the-number-of-water-molecules-of-a-hydrate-based-on-mass-loss-u |
Question: <p>We have to figure out what the water hardness in mg/L or ppm is for a $\pu{20ml}$ solution of $\pu{0.400M}$ $\ce{CaCl2}$. </p>
<p>We learned that the formula for hardness is mg/L of calcium carbonate per liter. I started by calculating that there would be $\pu{0.801 g}$ of $\ce{CaCO3}$ precipitate if reac... | https://chemistry.stackexchange.com/questions/37944/calculate-water-hardness-from-grams-of-caco3 |
Question: <p>I am a bit confused on how to account for the stoichiometry of a reaction as follows:</p>
<p>$$\ce{A}(s) + \delta \ce{B}(g) \ce{->} \ce{C}(s) + \delta \ce{D}(g)$$</p>
<p>The solid $\ce{A}$ is stationary in the reactor, and gas $\ce{B}$ flows through it with known inlet molar flow rate. Since 1 mol of ... | https://chemistry.stackexchange.com/questions/39498/stoichiometry-in-gas-solid-flow-system |
Question: <p>The equation for the burning of octane:</p>
<p>$$\ce{2C8H18 + 25O2 -> 16CO2 + 18H2O}$$</p>
<ol>
<li>How do i find the number of moles of carbon dioxide which is produced when one mole of octane burns ?</li>
<li>How do i find , at what volume , at STP , is occupied by the number of moles determined in... | https://chemistry.stackexchange.com/questions/40921/stoichiometric-calculations-for-the-combustion-of-octane |
Question: <p>The reason given for balancing chemical equations is the law of conservation of mass. They say that we balance equations with keeping in mind that atoms of every element included in the reaction must be equal on both sides of equations. And they just add some coefficients for this purpose. </p>
<p>But I a... | https://chemistry.stackexchange.com/questions/41390/validity-of-rationale-for-balancing-chemical-equations |
Question: <blockquote>
<p>Combustion analysis of a $\rm1.500~g$ sample of ascorbic acid yields $4.023\rm~g$ of $\ce{CO2}$ and $\rm0.96~g$ of $\ce{H2O}$. What is the empirical formula of ascorbic acid?</p>
</blockquote>
<p>Actually my question is that in many solutions I saw it's solved like that:</p>
<p>In $\ce{CO2... | https://chemistry.stackexchange.com/questions/46408/why-werent-the-moles-of-oxygen-calculated-the-same-way-as-c |
Question: <p><strong>How many atoms of Lithium are there in 14.3 grams of Lithium Fluoride?</strong>
I can't seem to single out how many atoms of Lithium are in lithium fluoride.</p>
<p>I know that the first step is to convert 14.3 grams to moles, so 14.3 multiplied by the molar mass of LiF divided by 1 is 0.55 moles.... | https://chemistry.stackexchange.com/questions/47849/how-many-atoms-of-lithium-are-there-in-14-3-grams-of-lithium-fluoride |
Question: <p>$\ce{2Ca3(PO4)2 +6SiO2 +10C->6CaSiO3 +P4 +10CO}$</p>
<p>What is the maximum amount of P4 that can be produced from 1.0 kg of phosphorite if the phosphorite sample is 75% $\ce{2Ca3(PO4)2}$ by mass</p>
<hr>
<p>The wording is confusing. I do not know what to do. Would you start by finding the limiting r... | https://chemistry.stackexchange.com/questions/48157/maximum-amount-of-p4 |
Question: <p>$\ce{2Ca3(PO4)2 +6SiO2 +10C->6CaSiO3 +P4 +10CO}$</p>
<p>What is the maximum amount of P4 that can be produced from 1.0 kg of phosphorite if the phosphorite sample is 75% $\ce{2Ca3(PO4)2}$ by mass</p>
<hr>
<p>I am confused. How do I find a maximum amount of a reaction</p>
Answer: <p>Phosphorite is a ... | https://chemistry.stackexchange.com/questions/48178/stoichiometry-assignment |
Question: <blockquote>
<p>Predict how the total pressure varies during the gas-phase reaction
$\ce{N_2}(g)+ 3 \ce{H2}(g) \rightarrow 2 \ce{NH3} (g) $ in a constant volume container. </p>
</blockquote>
<p>Reference: Atkin's Physical Chemistry, Tenth Edition, Chapter 20, Exercise 20A.1 (b) on page 870</p>
<p>My at... | https://chemistry.stackexchange.com/questions/54547/variation-in-pressure-for-a-gas-phase-reaction |
Question: <p>Problem : An organic compound containing carbon, nitrogen and oxygen will have a weight ratio $9:1:3$. The molecular weight of the compound is $108$. What is the formula of the compound?</p>
<p>I thought of calculating the empirical formula, but percentages are given for that, and not weight. </p>
Answer... | https://chemistry.stackexchange.com/questions/57897/how-do-i-find-the-formula-of-the-compound-given-the-ratio-of-its-constituents-by |
Question: <p>I know that the relation between Avogadro’s number and amu is a reciprocal relationship but the relation is slightly unclear.</p>
<p>Could anyone give me more clarification?</p>
Answer: <p>$\pu{1amu}$ is defined as one twelfth of the mass of one carbon-12 atom.</p>
<p>Avogadro's number is defined as the... | https://chemistry.stackexchange.com/questions/70135/what-is-the-relation-between-the-amu-and-avogadro-s-number |
Question: <p>My textbook had this question on balancing chemical reactions </p>
<blockquote>
<p>Ozone reacts with nitric oxide to give nitrogen dioxide and oxygen gas</p>
</blockquote>
<p>Here's how I balanced it: $$\ce{O3 + NO -> NO2 + O2}$$</p>
<p>However I realised that the equation is also balanced if I wri... | https://chemistry.stackexchange.com/questions/64202/more-than-one-way-of-balancing-a-chemical-equation |
Question: <p>How many liters of hydrogen, H2, are needed to react with 10 liters of nitrogen gas in the reaction forming ammonia?</p>
<p>$$\ce{3 H2(g) + N2(g) -> 2 NH3(g)}$$</p>
<p><strong>My try::</strong> Because we have 10 L of nitrogen gas, we have 10/22.4 moles = 0.446 moles of nitrogen gas, and thus need 0.4... | https://chemistry.stackexchange.com/questions/64333/how-many-liters-of-hydrogen-h2-are-needed-to-react-with-10-liters-of-nitrogen |
Question: <p>When diluting a mixture of two reactants with lets say a 100ml of H2O, how do you add this to the uncertainties of the concentrations of the reactants? Should the relative uncertainty of the added H2O be added to the relative uncertainty of the volume in both reactants? </p>
Answer: <p>When adding values ... | https://chemistry.stackexchange.com/questions/71658/help-with-uncertainties |
Question: <ul>
<li>I was wondering how I'd go around calculating the equivalent weight
of CaO. From my knowledge, the EW of a compound is its (given mass
)/(valence factor, n). Since CaO has no charge and no change in<br>
the oxidation number takes place, my valence factor comes out to be
0, which I know is wrong bec... | https://chemistry.stackexchange.com/questions/74410/equivalent-weight-for-cao |
Question: <p>I'm pretty new to chemistry and I've been stuck on it for hours.</p>
<p>Question: $\pu{10g}$ of the hydroxide of a metal on ignition gave $\pu{8g}$ of oxide. The equivalent weight of the metal is:<br>
a) $\pu{136g}$<br>
b) $\pu{40g}$<br>
c) $\pu{56g}$<br>
d) $\pu{28g}$ </p>
<p>I used the law of equivale... | https://chemistry.stackexchange.com/questions/76327/need-help-with-stoichiometry-problem |
Question: <blockquote>
<p>The equation below represents combustion of methane ($\ce{CH4}$, $\pu{16.04 g/mol}$). Balance the equation, and calculate the mass of water ($\pu{18.02 g/mol}$) formed when $\pu{40.0g}$ of methane is burned.
$$\ce{CH4(g) + O2(g) -> CO2 + H2O(g)}$$</p>
</blockquote>
<p>I have started t... | https://chemistry.stackexchange.com/questions/76548/how-to-calculate-mass-produced-when-a-given-gas-is-burned |
Question: <p>A colleague said we can’t dissolve a salt (whose solvation enthalpy is exothermic) faster if we increase the temperature (the solubility equilibrium product is not reached) because Le Chatelier‘s principle would favor the reactants.</p>
<p>For example, imagine dissolving NaOH(s) in distilled water, can’t t... | https://chemistry.stackexchange.com/questions/161619/reaction-kinetics-of-exothermic-reaction |
Question: <p><a href="https://i.sstatic.net/cMItP.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/cMItP.png" alt="enter image description here"></a></p>
<p>On an exam in organic chemistry I was asked why the reaction B proceeds faster than reaction A. </p>
<p>I answered that: in reaction B, I- is a bet... | https://chemistry.stackexchange.com/questions/100861/reaction-kinetics-organic-chemistry |
Question: <p>The addition of a catalyst is known to increase the rate constant of a reaction by providing an easier pathway for the reaction to occur, one with lesser activation energy. </p>
<p><em>My doubt is:</em></p>
<p>Is it possible that the addition of a catalyst, alters the <strong>order of a reaction</strong>... | https://chemistry.stackexchange.com/questions/86980/reaction-kinetics-and-catalyst-addition |
Question: <p><a href="https://i.sstatic.net/2srvk.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/2srvk.jpg" alt="enter image description here"></a></p>
<p>In this special reaction coordinate diagram with two reaction mechanisms, I tried to analyze it in two other ways, one with kinetics, another with e... | https://chemistry.stackexchange.com/questions/94751/reaction-coordinate-kinetics-equilibrium-in-example |
Question: <p>Specifically, I am interested in the reaction of different hydroxides (in aqueous form) with <span class="math-container">$\ce{CO_2}$</span>. I would like to determine which hydroxide would conduct the reaction the fastest. My initial thought would be that spectator ions would have no effect, and since the... | https://chemistry.stackexchange.com/questions/175496/can-spectator-ions-affect-reaction-kinetics |
Question: <p>This question has been bothering me for some time, and I can't seem to find a good answer online. </p>
<p>Say I have four chemical species $\ce{A}$, $\ce{B}$, $\ce{C}$, $\ce{D}$, and these four react in the following ways: </p>
<p>\begin{align}\ce{
A + A &-> B\\
A + B &-> C\\
A + C &-&g... | https://chemistry.stackexchange.com/questions/24506/reaction-kinetics-and-stoichiometry-mass-conservation |
Question: <p>According to the Arrhenius equation, the rate of reaction is proportional to $e^{-1/RT}$.</p>
<p>Here is a plot of the equation and its derivative with respect to temperature, both with respect to temperature. All constants are set to unity.</p>
<p><a href="https://i.sstatic.net/23Hut.png" rel="nofollow ... | https://chemistry.stackexchange.com/questions/67798/why-is-temperature-considered-as-an-important-factor-in-deciding-chemical-reacti |
Question: <p><img src="https://i.sstatic.net/8fKfm.png" alt="enter image description here"></p>
<p>How do I relate the half life to the overall rate of reaction? </p>
<p>I argued that from the data, doubling the partial pressure of either reactant, keeping the other constant, will half the half life. </p>
<p>So try ... | https://chemistry.stackexchange.com/questions/32561/reaction-kinetics-relating-half-life-to-reaction-rate |
Question: <p>We were taught that the kinetics of a reaction is determined by the reactions ‘rate determining step’ which is also the slowest step of the reaction. For E1 as well as E2 reactions the slowest steps are easily determined by the mechanism and I derived the rate laws for those. </p>
<p>In the case of E1cb r... | https://chemistry.stackexchange.com/questions/112482/kinetics-for-e1cb-reactions |
Question: <p>The rate constant for the reaction of hydrogen with iodine is <span class="math-container">$\pu{2.45E-4 M-1 s-1}$</span> at 302 °C and <span class="math-container">$\pu{0.905 M-1 s-1}$</span> at 508 °C.</p>
<p>a. calculate the activation energy and Arrhenius preexponential factor for this reaction.</p>
<p>... | https://chemistry.stackexchange.com/questions/178022/reaction-kinetics-exercise-for-hydrogen-iodide-synthesis |
Question: <p>In kinetics, zero order reactions are those reactions who are independent from the concentration of the reactant or the product. So their rate is equal to the constant <strong>k</strong>. But still we build the diagram where we find the correlation between concentration and time, where the slope is negativ... | https://chemistry.stackexchange.com/questions/30849/order-of-reactions-in-kinetics |
Question: <p>I was solving some problems on chemical kinetics, then I was just struck at some ques of sequential reaction kinetics. </p>
<p>Given reactions $$\ce{O_3 + Cl \rightarrow O_2 + ClO ~~~ k_1=5.2 \times 10^9~Lmol^{-1}s^{-1}}$$</p>
<p>and $$\ce{ClO + O \rightarrow O_2 + Cl ~~~ ~~~ k_2=2.6 \times 10^{10} ~Lm... | https://chemistry.stackexchange.com/questions/27466/sequential-kinetics |
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