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

0.18 mol

Step-by-step 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 * (1atm)/(101.3kPa) = 0.991atm`

Step 3: Calculate the moles of the gas

We will use the ideal gas equation.

`P * V = n * R * T\\n = (P * V)/(R * T) = (0.991atm * 4.5L)/((0.0821atm.L)/(mol.K) * 298K) = 0.18 mol`