Gases - Chemistry - page 273

Lesson 8-7 Review
1. [pressure]—Make sure that your units of pressure match the units that

come with the Ideal Gas Law constant.

2. [volume]—Make sure that your units of volume match the units that come

with the Ideal Gas Law constant.

3. [moles]—Remember: If you are given the mass of a substance, you can

convert to moles by dividing by the molar mass.

4 [temperature]—Make sure that your units of temperature match the units

that come with the Ideal Gas Law constant.

5. [Ideal Gas Law constant]—Some texts may use a different unit for one of

the quantities, changing the apparent value of this constant. You can,
however, convert back to the constant that we use in this topic.

6. [280 K]—Work shown following:

Given: P = 98.4 kPa; V = 60.0 dm 3 ; n = 2.5 moles;
R = 8.31 dm 3 × kPa/mole × K

Find: T

PV
nR

(98.4 kPa)( 6 0.0 dm 3 )
(2.5 mol)(8.31 dm 3 × kPa/mol × K) = 284.188 K = 280 K

Formula: T = =

7. [2.08 moles]—Work shown following:

Convert: 22.0 o C + 273 = 295 K

101.3 kPa
1 atm

1.50 atm = = 152 kPa

Given: P = 152 kPa; V = 33.5 dm 3 ; R = 8.31 dm 3 × kPa/mole × K;
T = 295 K

Find: n

PV
RT

(1 5 2 kPa)(33.5 dm 3 )
(8.31 dm 3 × kPa/mol × K)(295 K)
= 2.0771 moles = 2.08 moles

Formula:

n = =

8. [140 dm 3 ]—Work shown following:

Convert: 33.0 o C + 273 = 306 K
Given: P = 112.0 kPa; n = 6.0 moles; R = 8.31 dm 3 × kPa/mole × K;
T = 306 K

Find: V

V = nRT = (6.0 mol)(8.31 dm 3 × kPa/mol × K)(306 K)

(112.0 kPa)
= 136.22 = 140 dm 3

Formula:

P