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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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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'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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646 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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127 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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759 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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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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1answer
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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 $...
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How do I calculate the number of molecules in an equilibrium depending on a change in the equilibrium constant? [closed]

Consider 1000 molecules of $\ce{A}$ and 1000 molecules of $\ce{B}$ in a eucaryotic cell. The concentration of both will be about $\pu{10^-9 M}$. If the equilibrium constant $K$ for $\ce{A + B <--&...
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A metal, M, forms two fluorides containing 40.43% F and 50.44% F by mass. Identify the metal

A metal, $\ce{M}$, forms two fluorides containing 40.43 % $\ce{F}$ and 50.44 % $\ce{F}$ by mass. Identify the metal. I get that you can find out how much of the metal reacts with 1 mole of fluorine ...
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Stoichiometry and POAC Contradiction

Lets say we have the reaction $$\ce{H2 + O2 -> H2O}$$ And we are given 10 moles of $\ce{O2}$ and are asked that How many moles of hydrogen gas do we need to complete the reaction ? ...
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Why is potassium phosphate KH2PO4 in this reaction?

This is a continuation of this question because the first thing that came in my mind is that why potassium phosphate in this reaction is $\ce{KH2PO4}$ and not $\ce{K3PO4}$? In the wikipedia article ...
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How many liters of hydrogen, H2, are needed to react with 10 liters of nitrogen gas in the reaction forming ammonia?

How many liters of hydrogen, H2, are needed to react with 10 liters of nitrogen gas in the reaction forming ammonia? $$\ce{3 H2(g) + N2(g) -> 2 NH3(g)}$$ My try:: Because we have 10 L of nitrogen ...
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What is the meaning of a decimal in a subscript in a chemical formulas? [duplicate]

What is the meaning of a decimal in a subscript in a chemical formulas? I came across the fractional subscripts in a publication,[1] for example: We introduce oxygen into a ferromagnetic metallic ...
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Help balancing reaction between Iron (II) chloride and potassium phosphate

Very rusty with chemistry and looking to review some basics. Came across the following: Iron(II) chloride and potassium phosphate react. Write and balance the molecular, ionic, and net ionic ...
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More than one way of balancing a chemical equation

My textbook had this question on balancing chemical reactions Ozone reacts with nitric oxide to give nitrogen dioxide and oxygen gas Here's how I balanced it: $$\ce{O3 + NO -> NO2 + O2}$$ ...
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is avogadro's law for the same gas?

Avogadro's law is V1/n1 = v2/n2 - volume and number of moles are directly proportional. My question is - can this law apply to two different gases - for example, Hydrogen with volume v1 and number n1,...
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Ideal Gas Law: What is P? [closed]

I know P is the pressure, but is it the outside pressure or inside pressure? I know that in equilibrium, it doesn't matter, but then in this problem I got confused: 193 mL of O2 was collected over ...
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How to determine the equivalent weight of carbon dioxide correctly?

I just started learning about equivalent weight and encountered this solved example. Problem Statement: $4.215~\mathrm{g}$ of a metallic carbonate was heated in a hard glass tube and the $\ce{...
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Oxidation of malonic acid

Question How many grams $\ce{CO2}$ will result when burning $\pu{100 g}$ malonic acid? The formula for malonic acid is $\ce{C3H4O4}$ so 3 $\ce{CO2}$ molecules should result from oxidating one ...
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Multiple solutions in the balancing of redox reactions

While looking at the reaction between potassium permanganate and hydrogen peroxide in the presence of sulfuric acid a friend and I were attempting to find a general equation to yield the coefficients ...
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Why are there so many reactions for the discharge of LiCoO2?

I've just managed to understand a bit the meaning of having the notation of 0.5 in a molecular formula, when I found a set of multiple notations for the same discharge process that started to confuse ...
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How can there be decimal subscripts in a molecular formula?

While learning about how batteries work I have encountered the following notation for a Li-ion cathode: $\ce{Li_{0.5}FePO4}$.[1] According to Wikipedia, the subscript number in a reaction equation ...
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Balance redox equation with only one product

Is it possible to balance this equation using the half reaction method? $$\ce{Au + Cl2 + HCl⟶HAuCl4}$$ I know that the equation balanced would be: $$\ce{2Au + 3Cl2 + 2HCl⟶2HAuCl4}$$ However, how ...
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Do I have to consider the water in the hydrate of a salt in a mass percent calculation?

When calculating the mass percent of an element in a compound, I understand that you divide the molar mass of the element by the molar mass of a compound. In a case such as $\ce{NH4MgPO4.6H2O}$ is ...
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Balancing the equation

I've got a question: $$\ce{Cr2O7^2- -> Cr^3+}$$ This reaction takes place in a acidic medium - how many $\ce{H+}$ are required to balance the equation? How do I balance this reaction. Cr had ...
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Producing NaCl from 2 Na and Cl2

I want to react 250 g of $\ce{Na}$ and enough $\ce{Cl2}$ to produce $\ce{NaCl}$ and see how many grams of $\ce{NaCl}$ I can get. I guess I should create a scheme like this ...
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Given an unbalanced chemical equation, is it possible to determine the largest possible coefficient that could be used in the balanced equation?

I am writing a program to balance chemical equations, and would love to know if there is an algebraic way to determine the greatest possible coefficient that I would need to check.
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How do I know what the end products of the reaction of glucose and fructose?

I am unsure about why the end products of the reaction are what they are. Let's say I was combining glucose and fructose in a dehydration synthesis reaction to create sucrose. The equation is: $$\ce{...
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Beryl is a mineral which contains 5.03% Be, 10.4% Al, 35.5% Si and 53.58% O. What is the simplest formula for beryl?

So I tried to follow a 3 step rule to solving this equation: Divide each % by it's own atomic mass Dived each of those by whichever is smallest Find the lowest whole # Be = 5.03% / 9 = .558 ...
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Brackets in chemical formulas

When you have brackets such as $\ce{Zn(NO3)2}$, if there is a coefficient around the formula such as $\ce{2Zn(NO3)2}$, how would you read this? Would there be 2 zinc atoms, 4 nitrogen and 12 oxygen ...
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Which of the following samples contains the largest number of atoms?

Which of the following samples contains the largest number of atoms? a.    2.0 moles of $\ce{H3PO4}$ b.    3.0 moles of $\ce{H2SO3}$ c.    4.0 moles of $\ce{HNO3}$ d.    6.0 moles of $\ce{...
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Does titration usually always involve neutralization?

I've been doing titration exercises that involve figuring out the molarity of an unknown solution when you know the molarity of another (so like knowing the molarity of solution A but figuring out the ...
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Balancing the reaction equation for the oxidation of lead(II) sulfide with ozone

While I was reading about the chemical reactions of ozone, I came across this reaction. $$\ce{PbS + 4O3 -> PbSO4 + 4O2}$$ Though the reaction seems well balanced, but when I attempted to balance ...
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How to calculate the number of atoms of each element in a urea?

I have a stoichiometry question which I answered incorrectly and I am not sure where I went wrong. The question is as follows: Urea, $\ce{(NH2)2CO}$, is used for fertilizer and many other things. ...
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How to calculate the amount of substances product produces from the masses and amounts of starting materials?

Calculate the amount of carbon dioxide formed when we burn 1 mole of carbon in the presence of 16 g of dioxygen. $$\ce{C + O2 -> CO2}$$ 1 mole of carbon means 12 g. Therefore amount of ...