Questions: A 2.70-g sample of a gas occupies 15.0 L at 2.00 atm and 273 K. What is the molar mass of the gas?
Molar mass = g / mol
Transcript text: A 2.70-g sample of a gas occupies 15.0 L at 2.00 atm and 273 K . What is the molar mass of the gas?
Molar mass = $\square$ $\mathrm{g} / \mathrm{mol}$
Submit Answer
Try Another Version
1 item attempt remaining
Solution
Solution Steps
Step 1: Identify the Given Variables
We are given the following information:
Mass of the gas, \( m = 2.70 \) g
Volume of the gas, \( V = 15.0 \) L
Pressure of the gas, \( P = 2.00 \) atm
Temperature of the gas, \( T = 273 \) K
Step 2: Use the Ideal Gas Law
The ideal gas law is given by:
\[ PV = nRT \]
where:
\( P \) is the pressure
\( V \) is the volume
\( n \) is the number of moles
\( R \) is the ideal gas constant (\( R = 0.0821 \) L·atm/(mol·K))
\( T \) is the temperature
Step 3: Solve for the Number of Moles
Rearrange the ideal gas law to solve for \( n \):
\[ n = \frac{PV}{RT} \]
Substitute the given values:
\[ n = \frac{(2.00 \, \text{atm})(15.0 \, \text{L})}{(0.0821 \, \text{L·atm/(mol·K)})(273 \, \text{K})} \]
Calculate \( n \):
\[ n = \frac{30.0}{22.4133} \approx 1.338 \, \text{mol} \]
Step 4: Calculate the Molar Mass
The molar mass \( M \) is given by:
\[ M = \frac{m}{n} \]
Substitute the values for \( m \) and \( n \):
\[ M = \frac{2.70 \, \text{g}}{1.338 \, \text{mol}} \approx 2.018 \, \text{g/mol} \]
Final Answer
The molar mass of the gas is:
\[
\boxed{2.018 \, \text{g/mol}}
\]