Question

If I have an unknown quantity of gas at a pressure of 123 kPa, a volume of 31 liters, and a temperature of 360 K, how many moles of gas do I have?

Answer 1

To determine the number of moles of gas, you can use the ideal gas law equation:

PV = nRT

where: P = pressure (in kilopascals, kPa) V = volume (in liters, L) n = number of moles of gas R = ideal gas constant (8.314 J/(mol·K)) T = temperature (in Kelvin, K)

To use the ideal gas law, you need to convert the pressure to Pascals and the temperature to Kelvin:

1 kPa = 1000 Pa 360 K

Let's substitute the values into the equation and solve for n:

(123 kPa)(31 L) = n(8.314 J/(mol·K))(360 K)

First, let's convert the pressure to Pascals:

123 kPa = 123,000 Pa

Now, let's solve for n:

(123,000 Pa)(31 L) = n(8.314 J/(mol·K))(360 K)

3,813,000 = n(8.314)(360)

3,813,000 = 2990.104n

n = 3,813,000 / 2990.104

n ≈ 1275.3

Therefore, you have approximately 1275.3 moles of gas.