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.

Filter by
Sorted by
Tagged with
-1
votes
0answers
12 views

How do we find the limiting reagent of a reaction eithout knowing what the elements are? [closed]

*The black atom is A, white is B Question 2: If there are 6.0L of A, what is the final volume?
-1
votes
0answers
15 views

How many grams of K2CrO4 are formed from 65.2g of K2CO3? [closed]

4 FeCr2O7 + 8 K2CO3 + O2 ---> 2 Fe2O3 + 8 K2CrO4 + 8 CO2 I got 91.6 g but I'm not sure.
-3
votes
0answers
26 views

How many grams of AgCl can be produced from 107.0 moles of AgNO3 [closed]

NaCl + AgNO3 yields AgCl + NaNO3 My answer was in the ten thousands, but I'm not sure if it's right. Can anyone check it for me?
-3
votes
1answer
46 views

Preparation of Ca/PO4/acetate solution

EDIT: This is not a homework problem and we need this for an exploratory study on teeth demineralization. There is further work planned around this activity, which may not be relevant to the question. ...
-1
votes
0answers
13 views

After the reaction goes to completion, what will be the partial pressure of O2? [closed]

![ Into an empty container, 66 grams of SO2 and 39 grams of O2 are added. The following reaction then occurs at a constant temperature of 29 °C and a constant volume of 10 L: 2 SO2 (g) + O2 (g) ---> 2 ...
-4
votes
2answers
94 views

What is the mass of ozone present in 10.6 g of Na2CO3?

I got a question in my textbook asking for the mass of oxygen present in 10.6 grams of $\ce{Na2CO3}$. Why are they asking about the mass of oxygen? Does this refer to $\ce{O2}$? Shouldn't it be the ...
2
votes
1answer
3k views

How to assign oxidation number of sulfur in thiocyanate anion?

Recently I was trying to balance a redox chemical equation: $$\ce{CuSCN + KIO3 + HCl <=> CuSO4 + KCl + HCN + ICl + H2O}$$ The equation is in principle simple to solve; one element ($\ce{I}$) ...
0
votes
1answer
86 views

Equivant mass of double salt

What is the equivalent mass of double salt like dolomite? And what if the double salt is hydrated? Is a double salt taken as a single unit while equating the gram equivalent in any reaction? For ...
0
votes
2answers
59 views

Finding molarity of hyposulfite solution used in titration

$\pu{0.1 g}$ of $\ce{KIO3}$ is treated with excess $\ce{KI}$ solution. The liberated iodine required $\pu{44 ml}$ of $x$ molar hypo solution. Calculate the value of $x$. I have used the equivalent ...
0
votes
1answer
90 views

Gravimetric analysis

In a gravimetric determination of phosphorus an aqueous solution of dihydrogen phosphate ion is treated with the mixture of ammonium and magnesium ions to precipitate magnesium Ammonium Phosphate. ...
0
votes
0answers
33 views

Balanced equation for Schweizer's reagent production?

In Thompson's Illustrated Guide to Home Chemistry Experiments the chemical formula for Schweizer's reagent is represented as $\ce{[Cu(NH3)4](OH)2}$ (although Wikipedia represents it as $\ce{[Cu(NH3)4(...
3
votes
0answers
33 views

Molar ratios not leading to complete reaction in Schweizer's reagent production

In my home lab, I've reacted $\ce{Cu(OH)2}$ with aqueous ammonia to produce Schweizer's reagent. However, I'm surprised by the amount of ammonia required to react with this amount of $\ce{Cu(OH)2}$. ...
0
votes
2answers
42k views

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. ...
-1
votes
1answer
39 views

Rate Expression with two products

Consider the two following cases Case 1: Two Same Products Given the following chemical reaction, $$A + B \rightarrow C + C$$ where C are radicals, therefore I am not writing $2C$ on the right ...
0
votes
1answer
58 views

How can normalities be interchangeably used?

So I was doing the following question on stoichiometry . The part $\pu{1.80N}\ \ce{HCl}$ can also be written as $\pu{0.9 N}\ \ce{ H_2SO_4}$ but I don't understand why . $\pu{10 g}$ sample of 'gas ...
2
votes
1answer
31k views

How to calculate valence factor (n-factor) for a element?

Suppose I am given some reaction in which $$\ce{C6H12O6 -> CO2}$$ and I want to calculate n-factor for this reaction to ultimately calculate equivalent weight of carbon for this reaction. Since $$...
4
votes
1answer
7k views

What is the amount of nitrate ions in 20 g of Fe(NO3)3?

What is the amount of nitrate ions in $20.0\:\mathrm{g}$ of $\ce{Fe(NO3)3}$? The chemical formula for the nitrate ion is $\ce{NO3}$, I think. The molar mass of $\ce{Fe(NO3)3}$ is $242~\mathrm{g~mol^{...
0
votes
1answer
822 views

what is the mass of chromium in this sample?

If the total number of atoms in a sample of potassium dichromate is $2.13\cdot10^{24}$ , then the amount of chromium in this sample is? the answer that I've come up with is $367.64\ \mathrm g$ but in ...
1
vote
1answer
7k views

How to find the number of hydrogen atoms in 0.5 mol of hydrogen gas?

How do I calculate the number of hydrogen atoms in $\pu{0.5 mol}$ of hydrogen gas? I presume the answer would probably somehow use the equation $$n = \frac{m}{M},$$ where $n$ is the amount of ...
8
votes
3answers
7k views

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 ...
-1
votes
1answer
57 views

What is the physical meaning of the statements like “weight percentage of FeO in Fe”? [closed]

I have always had the notion of calculating weight percentage of Fe in FeO. It always seems that we are to calculate at times the weight percentage of FeO in Fe.Particularly when one weight percentage ...
0
votes
1answer
85 views

How do I solve this problem on mass balance from blast furnace iron making?

Question An ironmaking blast furnace produces hot metal of the composition: $\pu{93.6\%}$ $\ce{Fe},$ $\pu{2.1\%}$ $\ce{Si},$ $\pu{3.6\%}$ $\ce{C},$ $\pu{0.7\%}$ $\ce{Mn}.$ The composition of the ...
0
votes
1answer
81 views

How to calculate the relationship between the pressures of zinc, carbon monoxide, and carbon dioxide based on mole balance?

Zinc oxide is reduced at a constant temperature in a closed reactor using $\ce{ZnO(s)}$ and $\ce{C(s)}$ as the only starting materials. The following reactions are assumed to be at thermodynamic ...
1
vote
2answers
9k views

Air contain 20 % O2 by volume. How many cm³ of air will be required for oxidation of 100 cm³ of acetylene?

Air contain 20 % $\ce{O2}$ by volume. How many cm³ of air will be required for oxidation of 100 cm³ of acetylene? (a) 1064 cm³ (b) 212.8 cm³ (c) 500 cm³ (d) 1250 cm³ Answer: (d) My ...
1
vote
0answers
44 views

Why are the equilibrium exponents stoichiometric when the rate law's are not? [duplicate]

I'm learning about rate law and equilibrium, and the textbook really hammers in that the exponents for the rate law must be determined experimentally - you can't just use the coefficients from the ...
0
votes
0answers
31 views

Question based on finding impurity of a sample of Sodium bicarbonate

12.5g of commercial sodium bicarbonate gives 3 g of carbon dioxide. What is the percentage in purity in the sample? $$\ce{2NaHCO_3 -> Na_2CO_3 + CO_2 + H_2O}$$ I have solved this question, but I ...
1
vote
1answer
209 views

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 ...
0
votes
0answers
31 views

How do you find the heat capacity ratio of combustion products?

For example, if gaseous oxygen $(O_2)$ and paraffin wax $(C_{32}H_{66})$ were to stoichiometrically combust at STP, how would one go about finding the heat capacity ratio ($\gamma={c_p \over c_v}$) of ...
-2
votes
1answer
49 views

Why do we need to use oxidation number in order to balance a complex chemical reaction easily in an acidic or alkaline medium? [closed]

I have been trying to balance this chemical reaction in an "acidic" medium without using oxidation number or ion electron method: [$\ce{Fe^2+ + Cr2O7^2- -> Cr^3+ + Fe^3+}$]. Though I can balance ...
0
votes
0answers
65 views

Finding initial mole fraction of ammonia in ammonia-hydrazine mixture using thermodynamic parameters before and after thermal decomposition

A mixture of $\ce{NH3}$ and $\ce{N2H4}$ is placed in a sealed container at $\pu{300 K}$. The pressure within the the container is $\pu{0.6 atm}$. The container is heated to $\pu{1000 K}$ where the ...
2
votes
2answers
2k views

Sodium azide to Nitrogen ratio in airbags

I've been given this question and I don't know how to solve it. Airbags are designed to protect the occupants of a car during a collision. They use the decomposition of sodium azide, $\ce{NaN3}$. ...
1
vote
2answers
48 views

How do I do stoichiometry for 2 limiting reactants

The Drano reaction produces sodium aluminate along with hydrogen gas. If a typical container of Drano weighs 500 g which is 35% by weight by weight sodium (l) hydroxide and 2.5% by weight aluminum, ...
0
votes
0answers
59 views

Why decanted solution should be colorless when determining formula of unknown chloride?

I was following the guide “Stoichiometric Determination: Empirical Formula of Copper Chloride”. Under the Procedure section the following reaction is given: Producing solid $\ce{Cu}$ from a $\ce{Cu(...
0
votes
1answer
49 views

What is the cause of decrease in volume of gaseous mixture in the following problem? [closed]

I am studying Gaseous State. The problem says: A mixture of gas contains $\ce{N2}$ and $\ce{C2H2}$. $\pu{20 \\mL}$ of this mixture is added to $\pu{70\\mL}$ of $\ce{O2}$ and combustion is allowed to ...
0
votes
1answer
90 views

Will the volume occupied by a mixture of nitrogen and water be same as the volume occupied by them individually?

I am currently studying gaseous state and I encountered the following problem. A container with a volume 3 liter holds $\ce{N2(g)}$ and $\ce{H2O(l)}$ at $\pu{29 ^\circ C}$. The pressure is found to ...
-2
votes
2answers
35 views

Proust's law/Laws of definite proportion [closed]

As per laws of constant proportion/Proust's law,Ratio of elements by mass is always constant. But in case of H2+O2 →H2O Here when the chemists might have measured H2 and O2 individually they might ...
1
vote
1answer
54 views

Balancing chemical reactions, issues of Gauss's elimination method [duplicate]

I am trying to balance some chemical reactions by using the Gauss' elimination method and I noticed that this method does not work if the creation of a matrix with exactly one degree of freedom is not ...
0
votes
1answer
40 views

Why are yields of some chemical reactions so dependent on the stoichiometry of the reagents? [closed]

Back in chemistry class in high school I was working with a partner doing a chemical reaction. We measured the amounts of reagents well, but not perfect, and our yield suffered greatly. On the other ...
1
vote
0answers
20 views

Methods and observations that help you achieve complete decomposition of a compound in decomposition analysis [closed]

Different chemicals decompose in different ways to give different observations, but they usually involve heating the compound to high temperatures. My question is that what are your lab techniques ...
2
votes
1answer
37 views

What value should I use for P in the ideal gas equation for an unknown molar quantity?

I did a chemistry lab, in which baking soda and vinegar were reacted in a ziplock bag, and I was to calculate the proper quantity of reactants to fill the bag with CO2. The molar quantity of gas was ...
9
votes
1answer
31k views

How to find the molecular formula for a hydrocarbon compound from known combustion products?

What is the molecular formula of a compound containing only carbon and hydrogen if combustion of $1.05~\mathrm{g}$ of the compound produces $3.30~\mathrm{g}~\ce{CO2}$ and $1.35~\mathrm{g}~\ce{H2O}$ ...
4
votes
0answers
48 views

What does “at%” mean and how it differs from “mol%”?

Sorry if my question is a bit obvious, but for some reason I'm getting confused with the percentages in this question: Concentration of $\ce{A}$ is $\pu{80 at\%}$ and concentration of $\ce{B}$ is $...
0
votes
1answer
70 views

Why do we use coefficients for RFM (relative formula mass) in atom economy? [closed]

Usually when calculating using moles = mass / RFM, the coefficient is not multiplied by a compound's RFM to calculate RFM. But in calculations for atom economy, the (balanced) coefficient of a ...
4
votes
1answer
350 views

Reaction between copper(II) iodate and iodide

I was attempting the following question from IChO 1989, which involved balancing of redox equations. One may just expect this to be a typical iodate-iodide redox reaction, usually employed in ...
4
votes
2answers
5k views

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 ...
0
votes
0answers
29 views

Two different answers obtained by balancing this chemical equation!! Somehow [duplicate]

This is the concerned equation: $\ce{ XeF4 + H2O -> Xe + XeO3 + HF + O2}$ This can be balanced as $\ce{6 XeF4 + 12 H2O -> 4 Xe + 2 XeO3 + 24HF + 3 O2}$ or $\ce{5 XeF4 + 10H2O ->3 Xe + ...
4
votes
1answer
66 views

Is the kilogram still consistent with the old definition?

My old understanding was that a gram is the amount of mass in a cubic centimeter of water. But then I recently learned that the second was redefined to be some 9 billion cycles of a Caesium atom. ...
5
votes
1answer
381 views

What do the half-reactions need to be for balancing a redox reaction in an acidic medium?

Balance the following reaction: $$\ce{CuS + SO4^{2-} -> CuO + SO2}$$ Below, the number mentioned in the parenthesis is the oxidation number of sulfur. I have found out that the oxidation half-...
1
vote
1answer
899 views

Determine the amount of substance of calcium chloride used

Determine the amount of substance (in moles) of calcium chloride used in this lab. (Hint: $0.20\rm~M$ means $0.20\rm~moles:1~L$) I made $96$ milliliters of $\ce{CaCl2}$ which would be $0.096\rm~L$...
3
votes
0answers
46 views

Mass of H2 in a balloon

Question A balloon of diameter $\pu{2 m}$ has a volume of $\pu{4190 dm^3}.$ It floats since it is given an up thrust equal to the mass of air it displaces. (Given: average $M_\mathrm{r}$ of ...