Questions tagged [stoichiometry]

Stoichiometry refers to the relationship between the amounts of substances of the reactants and the amount of substances of the formed products. This tag should be used for specific questions about chemical reaction equations.

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529 views

Balanced equation for the hydration of cyclohexene to synthesise cyclohexanol [duplicate]

I'm trying to determine the full balanced equation for a hydration of cyclohexene to synthesise cyclohexanol using concentrated sulfuric acid as catalyst and distillation as the extraction method. I'm ...
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648 views

Finding the molar concentration of reactant used

We were given this problem at my university, and I can't seem to figure out how it was solved. The question says we have $\ce{NaHCO3}$ and 100 ml of $\ce{HCl}$ react and one of their products is $\ce{...
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How can I convert weight percentage of calcium chloride hexahydrate to calcium chloride dihydrate? [closed]

I have a chemical formula with $27\%$ $\ce{CaCl2.6H2O}$ and $43\%$ water with the balance of $30\%$ being other chemicals. I want to convert the $\ce{CaCl2.6H2O}$ and water percentage to $\ce{CaCl2....
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How is the the law of chemical equivalence defined and what are its limitations?

I've heard that the law of chemical equivalence states that the gram equivalence of each of the reactants equals the gram equivalence of each of the products. But I'm facing difficulties in ...
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In a mixture of NaOH and Na2CO3, why doesn't phenolpthalein change its color until Na2CO3 is half neutralised?

Let us consider a mixture of $\ce{NaOH}$ and $\ce{Na2CO3}$. Based on what I have understood, double titration works in the below manner : Phenolpthalein turns pink when added to the mixture. As $\...
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Calculate the molarity of Na+ ions in 20 mL of a .130 M solution of Na2Cr2O7?

The answer is $\pu{0.260 M}$, but I keep getting $\pu{0.0052 M}$ because I thought the right way to do it was by multiplying $\pu{0.130 M}$ by $\pu{0.02 L}$, then multiplying by $2$ moles of $\ce{Na+}$...
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How to calculate atoms of *each* element in a compound

I am trying to do the following exercise in a chemistry workbook. I have searched over internet but I couldn't find or understand it. How many atoms of each element are found in: 5 moles $\...
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How to determine an unknown metal based on the reaction products with oxygen and fluorine?

The following question is, as it will probably be obvious, a homework question, however I have absolutely no idea how to progress with it beyond what I have already done. This is the question: $\pu{...
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Equivalent weight for CaO

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 ...
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How much KMnO4 is required for the complete oxidation of ferric/ferrous oxalate in acidic medium?

Find out the amount of $\ce{KMnO4}$ required for the complete oxidation of $\pu{5 mol}$ of an equimolar mixture of ferric oxalate and ferrous oxalate. I understand that $\ce{MnO4-}$ will be oxidised ...
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On what factors does the true reaction Stoichiometry depend when there are multiple valid options?

Consider the following unbalanced reaction: $$\ce{XeF4 + H2O -> Xe + XeO2 + HF + O2}$$ There are six variables to be solved, but only four equations linking them. I solved the set of equations ...
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Molar ratio of two oxides of the same metal

A certain "metal oxide" is made of the oxides $A$ and $B$ of the same metal. In the oxide $A$, the metal is divalent, and in B, the metal is tetravalent. By reduction with hydrogen of a quantity $a$ ...
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1answer
47 views

Chemistry Calculation Dilutions of Acid

I was presented with the following problem in my lecture and I am confused as to what to do. You are required to prepare $\pu{250 cm3}$ of $\pu{0.100 mol dm-3}$ HCl by diluting $\pu{0.600 mol dm-3}...
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467 views

Precipitation reaction stoichiometry?

I have a question where I do not understand the final step to solve...here it is: What will be the Strontium ion concentration remaining after 30.0 mL of 0.10 M Na2SO4 solution are added to 70.0 mL ...
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1answer
151 views

Oxide and chloride of a metal [closed]

I found this problem: The oxide of a metal contains 60.0% metal and the chloride of the same metal contains 25.26% metal (in mass percents). What are the possible formulas for the oxide and the ...
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127 views

Why doesn't hydroxide concentration equal concentration of carbonic acid and bicarbonate in a sodium bicarbonate solution?

To find the pOH of solution of $\pu{0.42 M}$ of $\ce{NaHCO3}$, given a $\ce{Kb}$ of $\pu{2.4E-8}$, my solution manual does the following steps: Reaction is similar to : $\ce{HCO3- + H2O <=> ...
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149 views

How to balance the redox reaction between bismuth(III) sulfide and nitrate anion?

I have to solve the following redox reaction which occurs in an acidic environment, using the half-equation method. $$\ce {Bi2S3_{(s)} + NO3-_{(aq)} -> BiO3-_{(aq)} + SO4^2-_{(aq)} + NO_{(g)}}$$ ...
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Calculating stoichiometry of a reaction between xenon and fluorine

Xenon and fluorine were mixed in a 1:1 ratio by volume and sealed in a vessel attached to a barometer. After some time, crystals were found to have formed on the walls of the vessel and the barometer ...
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Why is it wrong to calculate the amount of oxygen directly from the products of a combustion reaction?

I've been stumped by a question in my textbook concerning combustion analysis. A $\pu{0.5438g}$ sample of a liquid consisting of only $\ce{C}$, $\ce{H}$, and $\ce{O}$ was burned in pure oxygen, ...
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Calculating a theoretical degree of polymerisation of ethylene oxide

This is the problem: Researchers add 88 grams of ethylene oxide. This reacts fully to 92 grams of poly ethylene oxide. Calculate the degree of polymerisation. I thought: molecular weight of ethylene ...
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Help with uncertainties

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 ...
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How to determine the theoretical concentration of the acetic acid solution in mol dm-3 of vinegar

How do you determine the theoretical concentration of an acetic acid solution in mol dm-3 of vinegar that is 5% acetic acid, knowing that the density of vinegar is 1.000g cm-3?
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What is the best approach to balance this equation? Why I cannot do it efficiently?

What is the best approach to balance this equation? $$\ce{CO2 + H2O <--> C2H2 + O2}$$ I did it at first this way and I was not successful: \begin{align} \ce{4CO2 + H2O &<--> C2H2 + ...
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Why does one of Dalton's compound elements with oxygen and phosphor consists of four atoms instead of two?

I stumbled across a peculiar detail while reading the chapter about the Chemical Revolution in Bowler and Morus' book Making Modern Science. According to this book, Dalton argued that compound ...
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51 views

Theoritical amount of Sodium Bicarbonate

I have to find the theoretical amount of sodium bicarbonate. The steps I followed in order to produce it are: 15g $\ce{NaCl}$ are added to a beaker. Then we add 87.5 mL of $\ce{NH3}(12M)$ We add 115g ...
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Finding the formula of an alcohol with a given molecular mass

Deduce the molecular formula of the alcohol that has molecular mass 158. I tried dividing this molecular mass (158) by the molecular mass of ethanol (46) to get a ratio, and then multiply the formula ...
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If there are multiple bases in solution and a strong acid is added, will both bases react?

For example, if there is one mole of carbonate ions ($\ce{CO3 ^2-}$) and sulfate ions ($\ce{SO4 ^2-}$) in a solution, and one mole of hydrochloric acid ($\ce{HCl}$) is added, will the one mole of ...
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Calculation of empirical formula from elemental analysis

A compound contains 40.0% Carbon, 6.7% Hydrogen, and 53.3% Nitrogen (by mass). Calculate the empirical formula. I'm getting $\ce{C7H14N8}$, but my professor says it is $\ce{CH2N}$. Which is the ...
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Can equivalent mass be more than the molecular mass? Can it be applied to radical reactions?

Consider a reaction involving radicals: $$\ce{CH3^. + Cl^. -> CH3Cl}$$ Is the definition of equivalent mass applicable here? If yes, how? Are there reactions where equivalent mass of a reagent ...
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Neutralization Reaction problem

$\frac x4$ equivalent of $\ce{NaAl(OH)2CO3}$ is neutralized by $x$ equivalent of $\ce{HCl}$ Milliequivalent of $$\ce{HCl}=\mathrm{{160}\times{0.25}\times{1}\times{40}}/100=16$$ $1$ is for one $\ce{H+...
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234 views

'Rate' in the rate law

I am slightly confused about what the rate is that is given by the rate law. Is it the rate of reaction (I.e. the rate of loss of reactant or formation of product divided by its stoichiometric ...
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What is the relation between the amu and avogadro’s number? [closed]

I know that the relation between Avogadro’s number and amu is a reciprocal relationship but the relation is slightly unclear. Could anyone give me more clarification?
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How to move forward in balancing this equation?

I want to get the molecular formula for this reaction: $$\ce{{$trans$-stilbene} + {$m$-chloroperoxybenzoic acid} -> {$trans$-1,2-diphenyloxirane}}$$ and if you do you get this: $$\ce{C14H12 + ...
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1answer
509 views

Stoichiometric reaction of hydrochloric acid, potassium nitrate, and copper

I have the following reaction involving these elements: $\ce{HCl}$ (hydrochloric acid) $\ce{KNO3}$ (potassium nitrate, a nitrate salt) $\ce{Cu}$ (copper) The reaction should produce nitrogen dioxide ...
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Why are the stoichiometric coefficients used as exponents in the chemical equilibrium constant?

From what I can ascertain, the formulation of the chemical equilibrium constant is somewhat arbitrary. I don't understand the motivation for putting the stoichiometric coefficients in the exponents. ...
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Law of mass action & Collision Theory

I don't understand why the stoichiometric coefficients of reactants and products are expotentialized in law of mass action. So I checked on Wikipedia. And this popped out: In the 1879 paper[9] the ...
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During the decomposition of sodium bicarbonate lab, the mass of the final solid I received was less than expected. Errors?

The lab procedure that my class used can be found in the photo attachment. The purpose of the lab was to determine the equation for the decomposition of sodium bicarbonate. The two possible equations ...
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How to calculate the heat released by the combustion of ethanol in excess oxygen?

I have a question in my textbook and I do not really understand their explanation of the answer, it is as follows: $$\ce{2CH3OH + 3O2 -> 2CO2 + 4H2O}$$ When 2 moles of $\ce{CH3OH}$ react with ...
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107 views

What is the molar mass of a compound with 0.5 atoms in its molecular formula?

I'm trying to calculate the theoretical specific capacity of the $\ce{LiFePO4}$ cathode for a fully discharged state, let's say when the cathode has the following notation $\ce{Li_{0.5}FePO4}$. And I'...
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How many grams of CuSO4*5H2O yield 10 grams of H2O?

If I want there to be 10.00 g of water in the copper (II) sulphate pentahydrate sample that I'm measuring, what mass of the substance will I need in order to have 10.00 g of water? I solved this ...
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Confusion regarding a stoichiometric formula

In a book, which contains only stoichiometry problems, I came across this formula. For any given compound $\ce{M_xN_y}$, $x \text{ Moles of N} = y \text{ moles of M}$ According to this rule if I ...
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489 views

How to calculate the percentage yield for a reaction with excess reagent?

A chemist mixed $12~\mathrm{g}$ of phosphorus with $35.5\ \mathrm{g}$ of chlorine gas to synthesize phosphorus(III) chloride (phosphorus trichloride). The yield was $42.4~\mathrm{g}$ of $\ce{PCl3}$. ...
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Determine chemical reaction stoichiometry?

Unfortunately my background on chemistry is very weak but I have to do some experiments in that field as a part of my project. Here is my problem: I am doing some leaching experiments on realgar (one ...
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Why can't I balance this reaction algebraically?

$$\ce{aCu + bHNO3 -> cCu(NO3)2 + dNO + eH2O}$$ (Source) I calculated: \begin{align} a &= c &(\ce{Cu})\\ b &= 2e &(\ce{H})\\ b &= 2c + d &(\ce{N})\\ 3b &= 6c + d + ...
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Percentage of yield reaction question

By bubbling $\ce{Cl2}$ in a solution containing $176.6~\mathrm{g}$ of $\ce{MgBr2}$ are obtained [sic!] $135~\mathrm{g}$ of $\ce{Br2}$. However, the yield of this reaction is not $100~\%$. How many ...
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Why is finding [H+] when given [OH-]= 3.57e-5 M wrong when I use -log[OH-]?

Question/Problem I know that [H+][OH-]=$10^{-14}$ And the problem asks to find out the concentration of H+ when the concentration of OH- is $3.57*10^{-5}$M By using the equation above i find that ...
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Stoichiometry Chemistry Lab: Copper (II) Sulphate Pentahydrate and Iron Single Displacement Reaction?

In my grade 11 chemistry class, we performed a lab in which we added 1.00g of iron to 6.00g of copper (II) sulphate which was dissolved in water. Using stoichiometry, we predicted that if the iron was ...
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Do moles of an acid and base have to be exactly equal for neutralization to occur?

I'm supposed to prove whether a statement is true or false: 5 moles of sodium hydroxide will neutralize $\ce{250 cm^3}$ of hydrochloric acid of concentration $\ce{10 mol/dm^3}$. So far, I've ...
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32 views

If propane with specific parameters were to combust in open air, what is actual volume of CO2 produced

Lets say we have a sample of propane gas having a volume of 2.70 L at standard room temperature and 1.75 atm. This gas is exposed to our air. The equation that governs this reaction is: $mC_3H_8 + ...
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158 views

How to solvethis problem related to redox titration?

A $1.0\ \mathrm{g}$ sample containing $\ce{BaCl2*2H2O}$ was dissolved and an excess of $\ce{K2CrO4}$ solution added. After a suitable period, the $\ce{BaCrO4}$ was filtered, washed and redissolved in $...