Verified answer

SOLUTION:

Step 1: List the given values.

The temperature and pressure of an ideal gas at STP are 273.15 K and 1.00 atm, respectively.

[tex]\begin{aligned} & P = \text{1.00 atm} \\ & V = \text{0.280 L} \\ & T = \text{273.15 K} \\ & mass = \text{0.400 g} \end{aligned}[/tex]

Step 2: Calculate the number of moles of gas using ideal gas equation.

[tex]\begin{aligned} n & = \frac{PV}{\text{RT}} \\ & = \frac{(\text{1.00 atm})(\text{0.280 L})}{\left(0.082057 \: \dfrac{\text{L}\cdot\text{atm}}{\text{mol}\cdot\text{K}}\right)(\text{273.15 K})} \\ & = \text{0.012492 mol} \end{aligned}[/tex]

Step 3: Calculate the molar mass of the gas.

[tex]\begin{aligned} MM & = \frac{mass}{n} \\ & = \frac{\text{0.400 g}}{\text{0.012492 mol}} \\ & = \boxed{\text{32.0 g/mol}} \end{aligned}[/tex]

Hence, the molar mass of the gas is 32.0 g/mol.

[tex]\\[/tex]

#CarryOnLearning