Question

A gas occupies a volume of 4.5 L at a temperature of 25oC and a pressure of 100.4 kPa. How many moles are in the sample?

Answer 1

Answer:

0.18 mol

Explanation:

Given data

• Volume (V): 4.5 L

• Temperature (T): 25°C

• Pressure (P): 100.4 kPa

Step 1: Convert the temperature to Kelvin

We will use the following expression

K = °C + 273.15

K = 25°C + 273.15

K = 298 K

Step 2: Convert the pressure to atmospheres

We will use the relation 1 atm = 101.3 kPa.

$100.4kPa \times \frac{1atm}{101.3kPa} = 0.991atm$

Step 3: Calculate the moles of the gas

We will use the ideal gas equation.

$P \times V = n \times R \times T\\n = \frac{P \times V}{R \times T} = \frac{0.991atm \times 4.5L}{\frac{0.0821atm.L}{mol.K} \times 298K} = 0.18 mol$