Stoichiometric Calculations: Limiting Reactants and Products

What is the primary requirement for performing stoichiometry calculations?

Knowledge of the atomic mass of each element
The total charge on both sides of the equation
A balanced equation (correct)
The number of atoms of each element on both sides of the equation

What is the definition of a mole in chemistry?

A unit of measurement for the concentration of a substance
A unit of measurement for the volume of a substance
The amount of substance that contains the same number of particles as there are atoms in 12g of carbon-12 (correct)
A unit of measurement for the mass of a substance

What is the role of the limiting reactant in a chemical reaction?

It is the reactant that has no effect on the reaction
It is the reactant that is present in excess
It is the reactant that determines the amount of product formed (correct)
It is the reactant that is not involved in the reaction

What is the relationship between the number of moles of a pure element and its atomic mass?

The number of moles is numerically equal to the atomic mass (A) Signup and view all the answers

What is the purpose of using the mole concept in the laboratory?

To quantify reactants and products (B) Signup and view all the answers

What is the consequence of having excess reactants in a chemical reaction?

The amount of product formed will be limited (C) Signup and view all the answers

What is the term for the reactant that is completely used up in a chemical reaction?

Limiting reagent (D) Signup and view all the answers

What is the main focus of stoichiometry?

Treating chemical equations as consisting of mathematical symbols/entities (C) Signup and view all the answers

What is the term for reactants that are not used up in a chemical reaction?

Excess reagent (A) Signup and view all the answers

What is the purpose of a balanced chemical equation?

To represent an equality, similar to an algebraic equation (B) Signup and view all the answers

What is the process that involves rearrangement of molecular or ionic structure of a substance?

Chemical reaction (B) Signup and view all the answers

What is represented by the arrow in a chemical equation?

The equal sign (C) Signup and view all the answers

What is the mole relationship between CaCO3 and HCl based on the balanced equation?

1mol CaCO3 : 2mol HCl (B) Signup and view all the answers

What is the formula weight of HCl?

36.46 amu (C) Signup and view all the answers

What is the molar mass of HCl?

36.46 g/mol (D) Signup and view all the answers

What is the unit of atomic weight?

atomic mass units (amu) (D) Signup and view all the answers

What is the purpose of mole relationships in stoichiometry?

To convert between moles of different reactants or products (A) Signup and view all the answers

What is the relationship between formula weight and molar mass?

Formula weight and molar mass have the same value, but different units (D) Signup and view all the answers

What is the molar mass of Fe2O3 calculated as?

2 atoms Fe x 55.85 g/mol Fe + 3 atoms O x 16.00 g/mol O (C) Signup and view all the answers

What is the purpose of using molar mass in stoichiometry problems?

To convert between grams and moles of a substance (B) Signup and view all the answers

What is the unit of molar mass?

grams per mole (g/mol) (A) Signup and view all the answers

What is the molar mass of Fe?

55.85 g/mol (C) Signup and view all the answers

What is the mole ratio of Fe2O3 in the sample problem?

5.00 g / 159.7 g/mol (B) Signup and view all the answers

What is the purpose of a balanced chemical equation in stoichiometry?

To specify the mole relationships of the reactants and products (A) Signup and view all the answers

What is the primary purpose of relating the mass of a substance to moles?

To make a conversion factor (B) Signup and view all the answers

What is the correct order of steps in a stoichiometry gram-to-mole calculation?

Identify what is required, write out conversion factors, set up and solve the problem (B) Signup and view all the answers

What is the molar ratio of oxygen to aluminum oxide in the reaction Al + O2 → Al2O3?

2:1 (A) Signup and view all the answers

How many moles of oxygen are needed to react with 3.75 grams of ammonia in the reaction NH3 + O2 → NO + H2O?

2.5 moles (D) Signup and view all the answers

What is the purpose of balancing a chemical equation in mole-to-mole calculations?

To ensure the equation is mathematically correct (B) Signup and view all the answers

How many moles of CO are produced from 3.5 moles of C2H6 in the reaction C2H6 + O2 → CO + H2O?

2.5 moles (C) Signup and view all the answers