2.3 Stoichiometry and mole rations

Exam 2

What is stoichiometry?

The study of the quantitative relationships between reactants and products in a chemical reaction.

What does a mole ratio come from?

The coefficients in a balanced chemical equation

In the equation: 2H₂ + O₂ → 2H₂O, what is the mole ratio of H₂ to H₂O?

2:2 or 1:1

What is the first step in any stoichiometry problem?

Convert the given quantity to moles.

What is the general plan for stoichiometry problems?

Given → moles of given → mole ratio → moles of unknown → final units (g, L, etc.)

How do you find the molar mass of a compound?

Add up the atomic masses of all the atoms in the formula (in g/mol).

Example: How many moles of H₂O are produced from 4.5 moles of O₂? (2H₂ + O₂ → 2H₂O)

(4.5 mol O₂) × (2 mol H₂O / 1 mol O₂) = 9.0 mol H₂O