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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Empirical and Molecular formula: Homework

I'm working on a high school chemistry book and want to double check one of the homework assignments. The question is for students to write the empirical and molecular formula for 1,2-dichloroethane. ...
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What is a simple ratio in which atoms combine?

According to Modern Atomic Theory: The ratio in which the different atoms combine may be fixed and integral but may not always be simple. The example given is that in sugar molecule the ratio of $\...
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Indonesian Chemical Olympiad: Calculating mass from predicted reaction

This problem is taken from the Indonesian Chemical Olympiad. A sample containing barium peroxide was added to a glass full of sulfuric acid. It produced an insoluble product and its filtrate. The ...
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C + O2 is equal to C + O, how is that possible

C + O = CO2 . This is because carbon has valency of 4 while oxygen has valency of 2. When they react the valencies are criss crossed which means we will get C2O4 but this is simplified to CO2. But ...
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CH4 + O2 => CO2 + 2H2, what's wrong with it?

It says in my textbook that: $$\ce{CH4 + 2 O2 -> CO2 + 2 H2O}$$ which seems like a displacement reaction to me. Shouldn't the reaction be: $$\ce{CH4 + O2 -> CO2 + 2 H2}$$ since $\ce{4H}$ ...
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Figuring out the theoretical mass of reactants?

Hi Stackexchange Community, I'm working on my chemistry lab report. The initial instructions were to test the hypothesis that the mass of products of a reaction will equal the mass of the reactants. ...
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How much potassium permanganate is needed to completely oxidize ferrous oxalate?

Amount of substance of $\ce{MnO4-}$ required to oxidize one mole of ferrous oxalate completely in acid medium will be: (a) 7.5 moles (b) 0.2 moles (c) 0.6 moles (d) 0.4 moles In ...
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Rate and order confusion

I just learned about rate and order... I just want to confirm if these three ideas are correct: If the first elementary step is the slow step, will the stoichiometric coefficients of the reactants in ...
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Would 2 C₂ be 2 moles of diatomic carbon, or 4 moles of carbon?

Would molecules like $\ce{C2, H2}$, etc., be considered 1 mole of diatomic [element] or 2 moles of [element]?
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Which ions are accounted for in total and net ionic equations?

There are a number of things I don't understand about ionic equations. First off, when you do net ionic equations, is it correct that you're only focusing on precipitates? The way I understood it, ...
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Calculating mass of krypton from mole fraction

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 ...
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220 views

How to find how much there is of a compound given the following information?

The detailed version of the question: If we burn a strip of magnesium in air, there will be two main products, magnesium oxide and magnesium nitride. If we then treat that mixture with water, the ...
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What is an equivalent?

I want to know what is an equivalent and how is it different from equivalent mass. How to calculate and why is it used in chemistry for knowing concentration?
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Units in stoichiometry

$$C_x H_y O_z$$ 1.What are the units of x,y,z.I've read that they're termed as 'stoichiometric coefficients'. 2.What is the unit of mass proportion of carbon(c) in the fuel? $$c=\frac{M_{carbon}}{...
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Molarity exercises [closed]

Can anyone direct me to a good book with lots of molarity exercises, i really want to practice this and would like to find as many types of exercises involving molarity. I of course did google this ...
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Gas law and moles

A sample of solid magnesium reacts with excess $\ce{HCl}$ solution to form hydrogen gas. The sample of gas measures $1.628\ \mathrm{L}$ at $22.0\ \mathrm{^\circ C}$ and $0.930\ \mathrm{atm}$ of ...
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How can zinc metal still be present after the reaction? [closed]

A $\pu{15.8 g}$ strip of zinc metal was placed in $\pu{100 ml}$ of silver nitrate. When the reaction was complete, the strip of zinc had a mass of $\pu{13.1 g}$. What was the concentration of the ...
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How do I find the ratio of the reaction of the residue and HCl?

A mixture weighing $4.08\ \mathrm g$ of $\ce{BaO}$ ($M(\ce{Ba})$ = $138\ \mathrm{g\ mol^{-1}}$) and an unknown carbonate $\ce{XCO3}$ was heated strongly. The residue weighed $3.64\ \mathrm g$. This ...
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How do I calculate the normality of NaBrO3?

Find the mass of $\ce{NaBrO_3}$ required to prepare $150 \text{ml}$ of $0.75N$ solution based on the reaction $$\ce{BrO_3^- +6H^+ +6e^- \bond{->}Br^- +3H_2O}$$ My analysis: $150 \text{ml}$ ...
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How are non-Stoichiometric compounds determined?

For solids where the compound contains defects, the stoichiometric equation deviates from the "pure" one. How are these compounds determined? I am looking in my chemistry book but I do not see ...
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Finding the percent of calcium carbonate in commercial antacid by using back titration

I'm an IB Chemistry student and I had to do a back titration lab where 1g of a powdered antacid tablet were mixed with 50mL 1M HCl, and the mixture was titrated using 0.2 M NaOH; the NaOH was to ...
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Amount of substance produced in chemical reaction

If $15.0\ \mathrm{mol}$ of nitrogen are reacted with $30.0\ \mathrm{mol}$ of hydrogen, how much ammonia will be produced? $$\ce{N2 + 3H2 -> 2NH3}$$ What I’ve tried is the following: $$\dfrac{n(\...
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Stoichiometry: efficiency

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." My method to do this is - one I learned from ...
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Copper oxidation

In an experiment we conducted, we heated 1.6 grams of copper dust, and got 1.7 grams of oxidised copper, (it probably reacted with 0.1 grams of $\ce{O2}$) and our goal was to find which of the two ...
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How to determine the concentration of a permanganate solution by redox titration?

I need to find the concentration of $\ce{KMnO4}$ as it is an unknown. It is a titration experiment between $\ce{KMnO4}$ and sodium oxalate solution. I assumed I had $25.00 \ \ce{ml}$ of $0.01003 \ ...
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Attempting to balance a redox reaction using half reactions leaves an unbalanced component

I have this redox reaction that I can't balance using half reaction method. $$\ce{Mg + HNO3 -> Mg(NO3)2 + N2O + H2O}$$ What I get at the end is $$\ce{2Mg + 6HNO3 -> 2Mg(NO3)2 + 3N2O +3H2O}$$...
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Can 1 mole of H2 react partially with one mole of O2?

I am currently studying stoichiometry (high school level) and we came across the following equation in school: $\ce{2H2 + 1O2 -> 2H2O}$ which is clear to me. We learned in school that reactions ...
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Law of Definite Proportion: Do the numbers indicating moles count?

I need to find the ratio of a substance as it converts from a bicarbonate to a carbonate: ex: $\ce{Fe(HCO3)2 -> FeCO3 + CO2 + H2O}$ $\ce{Fe(HCO3)2} / \ce{FeCO3}$ = $3/2$ *using molar ...
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Figuring out formula of a hydrocarbon from amount of products obtained and reactants used

One mole of a hydrocarbon is combusted. The products obtained are cooled down to STP and occupy a volume of $89.6\:\ell$. Oxygen required for conbustion was $145.6\:\ell$ at STP. Find the molecular ...
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How to determine the empirical formula for an unknown iron oxide?

I have to determine the empirical formula of an oxide of iron which has $69.9\%$ iron and $30.1\%$ dioxygen by mass in it. I have started as follows: For our convenience we take $\pu{100 g}$ of that ...
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Calcium carbonate and hydrogen phosphate producing calcium phosphate, carbon dioxide, and water

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 ...
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Find the volume of the carbon dioxide product

Below you can see the chemical reaction I'm working with: $$\ce{CH_3CH_2OH(l) + 3O_2(g) -> 2CO_2 (g) + 3H_2O(g)}$$ I've got so far: How can I calculate the volume of the product of carbon ...
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Empirical formula when given percentages?

A binary compound of lead and oxygen contains $90.66 \% \ce{Pb}$. What is the empirical formula for the compound? How do I use the percentage to get to the normal formula, then how do I change the ...
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Balancing a chemical equation [duplicate]

I'm in chemistry and I still have a hard time comprehending how to balance a chemical equation. What are the main steps and general things to know? thank you.
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Balancing a chemical equation, but with an incorrect mole ratio

I'm wondering if it's possible to balance a chemical equation with an incorrect mole ratio. I have the unbalanced equation $\ce{AgNO3 + Cu -> Ag + Cu(NO3)2}$, I have a $2:3$ ratio of $\ce{Cu}$ and ...
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Law of Multiple Proportions: What is the significance of small whole numbers?

I'm new to Chemistry and in my textbook, it describes the Law of Definite Proportions (aka Proust's Law) and then goes on to describe the Law of Multiple Proportions. The example they give is carbon ...
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How to compute molecular formula?

I have the following question to solve: Tungsten, $\ce{W}$, and chlorine, $\ce{Cl}$, form a series of compounds with the following compositions: \begin{array}{rr} \text{Mass % W} & \text{...