Gas Stoichiometry

Gas Stoichiometry

Grade 10A

Learning Objectives

• Understand how to convert gas values from Grams to Litres at STP

• Calculate Stoichiometric problems relating to gas values

Key words

• Mole

• Molar Mass

• STP

• Stoichiometry

• Molar volume

Stoichiomtery

• the study and calculation of quantitative (measurable) relationships of the reactants and products in chemical reactions (chemical equations)

• The Ideal Gas Law, along with a balanced chemical equation, can be used to solve for the amount, either in volume or mass, of gas consumed or produced in a chemical reaction.

At Standard Temperature and Pressure (STP), 1 mole of any gas will occupy a volume of 22.4 L.

Video 1

Molar Gas Volume

Multiple Choice

What volume will 3.1 moles of argon gas occupy at STP?

• 69L

• 69.4L

• 70L

• 70.4L

Multiple Choice

What volume will 0.75 moles of Nitrogen gas occupy at STP?

• 15L

• 16L

• 16.8L

• 15.8L

Video 2

How to convert grom grams to litres

Multiple Choice

In the equation: C2H4 + 3O2 --> 2CO2 + 2H2O. How many Liters of CO2 will be produced from 20g of C2H4

• 31.4L

• 28L

• 36L

• 32L

Multiple Choice

in the equation: 3N2H4O + 2HCL --> 3N2O + Cl2 + 7H2. How many litres of N2O are produced from 50g of N2H4O?

• 24.3L

• 22L

• 23.3L

• 25L

Video 3

Using PV=nRT to solve stoichiometric problems

Multiple Choice

8g of Calcium Oxide reacts with HCL to form Calcium Chloride gas and water. What volume of Calcium Chloride is produced at STP?

CaO + 2HCL --> H2O + CaCl2

• 3L

• 3.14L

• 4L

• 3.75L

Multiple Choice

Sulfuric acid reacts with excess ammonia to produce sulfur dioxide, Nitrous oxide and Hydrogen. The reaction takes place at 320k and 1.8atm. If 6L of sulfur dioxide are produced, how many grams of Sulfuric acid are needed?

2H2SO4 + N4H4 --> 4H2 + 2SO2 + 2N2O2

• 0.41g

• 42.4g

• 60g

• 40.18g

Stoichiometry Key points

• Write a balanced equation to find Molar/Coefficient ratios

• Use Mole x Molar mass = Mass formula triangle to find moles or mass

• Remember 1 mole of gas = 22.4L

• Use coefficient ratios to do mole to mole conversions. What you need to find on top, what you already have on the bottom.