Lesson: Reaction Masses Chemistry

In this lesson, we will learn how to calculate the masses of reactants and products using their formula masses, molar quantities, and ratios.

Lesson Plan

Students will be able to

calculate the molar ratio of reactants to products, and other reactants, using balanced chemical equations,
combine formula mass with actual mass to determine the masses of other reactants and/or products,
use balanced chemical equations to calculate the masses of reactants or products,
use the masses of reactants and/or products to determine balanced chemical equations for reactions,
use balanced equations to calculate the mass of a reactant or product from the number of moles (and vice versa).

Q1:

Methane burns in oxygen according to the following equation:

What is the molar ratio of methane to oxygen?

What is the molar ratio of methane to carbon dioxide?

What is the molar ratio of oxygen to water?

Q2:

Methane burns in oxygen according to the equation: The molar mass of methane is 16 g/mol, and the molar mass of molecular oxygen is 32 g/mol.

What is the ratio of the molar masses of methane and oxygen?

What is the ratio of the mass of methane to the mass of oxygen in this reaction?

What mass of oxygen is needed to for 1 g of methane to completely react?

Q3:

Sodium oxide reacts with hydrochloric acid to produce sodium chloride and water, according to the equation

What is the molar ratio of to ?

What is the molar mass of to the nearest whole number?

What mass of is required for 2.5 g of to completely react? Give your answer to 1 decimal place.