Question

If 2.3 mol of a gas occupies 50.5 mL how many moles of the gas will occupy 85.5 mL at the same temperature and pressure?

Answer 1

Using the ideal gas equation:
PV = nRT, we can form:
V/n = constant
Thus,
V₁/n₁ = V₂/n₂
n₂ = 2.3 x 85.5/50.5
= 3.89 moles

Answer 2

Answer: The number of moles of gas is 3.89 moles.

Explanation:

To calculate the number of moles for given volume, we use the equation given by Avogadro's Law.

This law states that volume is directly proportional to the number of moles of the gas at constant pressure and temperature.

$V\propto n$   (At constant temperature and pressure)

Or,

$\frac{V_1}{n_1}=\frac{V_2}{n_2}$

where,

$V_1\text{ and }n_1$ are initial volume and number of moles

$V_2\text{ and }n_2$ are final volume and number of moles

We are given:

$V_1=50.5mL\\n_1=2.3mol\\V_2=85.5mL\\n_2=?mol$

Putting values in above equation, we get:

$\frac{50.5mL}{2.3mol}=\frac{85.5mL}{n_2}\\\\n_2=3.89mol$

Hence, the number of moles of a gas is 3.89 moles.