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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333 views

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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287 views

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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1answer
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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 ...
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Finding x and y in Pt(NH3)xCly

Questions 8 and 9 refer to the analysis of a salt whose formula is $\ce{Pt(NH3)_xCl_y}$. $0.02$ moles [sic!] of this salt required $40.0~\mathrm{cm^3}$ of $2.0~\mathrm{mol\,l^{-1}}$ nitric ...
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How to make copper plating solution?

I intend to make the following composition of copper plating solution: \begin{array}{c:c} \rm material & \rm concentration \\\hline \rm Copper sulfate & \pu{200 \frac{g}{L}} \\ \rm ...
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733 views

Calculating the chloride concentration

What are the concentrations of $\ce{Cl-}$ in the following solution? $1.9\ \mathrm{g}\ \ce{MgCl2}$ is dissolved in water to make $1\ \mathrm{L}$ total solution $$48.31\ \mathrm{g/mol}\ \ce{MgCl2}$$ $...
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Balanced equation for neutralisation reaction betweeen potassium carbonate and hydrochloric acid

They seem all correct to me, is there any reason why one reaction would happen over the other(s)? $$\begin{align} \ce{K2CO3 + 2 HCl &-> 2 KCl + H2CO3}\\[6pt] \ce{K2CO3 + 2 HCl &-> 2 KCl ...
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Writing equation of reaction in stoichiometry of redox titrations

While solving some questions on the stoichiometry on redox titrations, I come across this question: Calculate the volume of $0.05\ \mathrm{M} \ \ce{KMnO4}$ solution required to oxidize completely $...
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Can a chemical reaction have two balanced equations?

I was recently studying Xenon compounds and read this reaction: $$\ce{6XeF4 + 12H2O -> 4Xe + 2XeO3 + 24HF + 3O2}$$ However this reaction can also be written as the following: $$\ce{4XeF4 + 8H2O ...
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How to make by dilution a certain ion concentration

The question I'm trying to answer is this: What volume of $0.25\ \mathrm{mol/l}$ calcium nitrate is required to make by dilution with water $500\ \mathrm{cm^3}$ of a solution with a nitrate ion ...
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How do I find the formula of the compound given the ratio of its constituents by weight? [closed]

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? I thought of ...
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How do we count charges in this example of a Redox reaction equation?

My brother(younger) had a doubt regarding this chemistry book example so I let him here : Question : Balance the equation : $\ce{H+ + MnO4- + Fe^2+ -> Fe^3+ + Mn^2+}$ Solution steps(as given by ...
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Calculate the mass of Mg needed to produce 5 kg of vanadium

I need to calculate the mass of magnesium needed to produce $\pu{5 kg}$ of vanadium from the following reaction: $$\ce{3Mg + 2VCl3 -> 2V + 3MgCl2}$$ given relative atomic masses for $\ce{Mg}$ and ...
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Why does multipying a scalar in both sides of a balanced chemical equation, change related quantities?

Stoichiometric coefficients appearing in a balanced chemical equation are unrelated to the actual concentration of reactant/products at any stage of a chemical reaction. They give information only ...
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How much volume of oxygen will be required for complete combustion of 40 ml of acetylene and how much volume of CO2 and H2O will be formed?

How much volume of oxygen will be required for complete combustion of 40 ml of acetylene and how much volume of $\ce{CO2}$ and $\ce{H2O}$ will be formed? After balancing the left-hand side produces 5 ...
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Variation in pressure for a gas phase reaction

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. Reference: Atkin's Physical Chemistry, ...
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Empirical formula, simplifying problems

Need some help with second part.....can't get it to be balanced and therefore can't find the formula and name! Thanks in advance! What is the empirical formula of each of the following compounds? a)...
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Coefficient in front of molecules in a chemical equation

In a chemical equation representing a chemical reaction what do the numbers in front of the molecules of compound and elements indicate? Do they signify number of molecules or moles or volume? ...
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Balancing by oxidation numbers method multiple atoms

In my Chemistry textbook, the rules for balancing a chemical equation using the oxidation-Number method are as follows: Assign oxidation numbers to all the atoms in the equation. Identify the atoms ...
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Dissolving limestone in HCl and then neutralising the solution with NaOH

$15.0~\mathrm{mL}$ of $1.4~\mathrm{M}\ \ce{HCl}$ was mixed with $1.00~\mathrm{g}$ of limestone (impure $\ce{CaCO3}$) until all the solid had dissolved. The solution was then transferred to a conical ...
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What happens when potassium iodide is added to a copper (II) salt?

$$\ce{Cu^2+ + KI -> ??}$$ I thought of this reaction: $$\ce{Cu^2+ + 2KI -> CuI2 + 2K+}$$ But since $\ce{CuI2}$ doesn't exist, the $\ce{I-}$ ions must reduce $\ce{Cu^2+}$ to $\ce{CuI}$ and ...
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Why convert to moles for stoichiometry calculations? [closed]

Why do you have to convert the reactants and products of an equation to moles when doing stoichiometry problems? Why can't you just convert straight to grams to solve the problem?
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Moles of Diatomic Molecules [duplicate]

Does "Mole of Iodine" or any other element that normally appears as diatomic molecules refer to a mole of single atoms ($6.02\times 10^{23}$ iodine atoms) or a mole of the molecules ($6.02\times 10^{...
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Preparing a 0.030 M solution of potassium ferrocyanide trihydrate?

I am a little bit confused on what I am supposed to do. The instructions say to prepare 250 mL of this solution by measuring out in grams the amount of PFT using a 250 mL volumetric flask. Then it ...
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1answer
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How to find the concentration of an of ammonia solution by titration with nitric acid?

I am stuck with this question I am doing: To determine the ammonia ($\ce{NH3}$) concentration in a cleaning product, a chemist diluted 20 mL of the product to 500 mL. Of the 500 mL solution, 25 mL ...