Moles and Gases

Achievement Indicators Determine relationships between molar

quantities of gases at STP define STP and state the molar volume of a gas at

STP (i.e., 22.4 L/mol)

determine experimentally the molar volume of a gas at room temperature and pressure

calculate the moles or mass of a gas from a given volume at STP or vice versa

Gases and Moles The volume occupied by a certain amount of

gas depends on the temperature and pressure

Standard Temperature and Pressure (STP) Standard Temperature 0°C (273 K) Standard Pressure 101.3 KPa (1

atmosphere)

The volume of one mole of any gas @ STP is…

22.4 L

The Molar Volume @ STP is

Only For Gases at STP

Flowchart

Moles Litres at

STP

Divide by 22.4L mol

Multiply by 22.4 L mol

Calculations1. Find the volume occupied by 0.600 moles of

CO2 at STP.

0.600mol x

= 13.4 L

22.41

Lmol

Calculations2. Find the number of moles in 264.0 mL

sample of NO2 at STP.

264.0 mL x x

= 1.18 x 10-2 mol

Homework p. 83 # 11 & 12

x (1mol / ?g)

x (?g / 1mol)

x (1mol / 22.4L)

x (22.4L / 1 mol)

Volume at STP

Mass(g) 1 MOLE

Calculations Find the volume occupied by 22.0 g of CO2(g)

at STP Plan: g mol L

22.0 g CO2 x x

= 11.2 L

Now You Trya) Find the mass of a 200.0 mL sample of NO2

(g) at STP. Plan mL L mol g

200.0 mL x x x

= 0.411g

b) Find the volume occupied by 3.60 Kg of fluorine at STP.

• Kg g mol L

3.60 Kg x x x

= 2.12 x 103 L

Homeworkp. 83 #11 & 12p. 86 & 87# 22 (b & i) #24 (a,c,e,g)