Question

how many moles of helium are in a 2 liter gas sample at 2 atm and 100 c ?
○ 4
○ 0.13
○ 0.08
○ 2

Explanation:

Step1: Convert temperature to Kelvin

$T = 100^\circ\text{C} + 273.15 = 373.15\ \text{K}$

Step2: Apply ideal gas law $n = \frac{PV}{RT}$

$P=2\ \text{atm}, V=2\ \text{L}, R=0.0821\ \frac{\text{L·atm}}{\text{mol·K}}$
$n = \frac{2 \times 2}{0.0821 \times 373.15} \approx \frac{4}{30.64} \approx 0.13$

Answer:

B. 0.13