Question

Calculate the mass in kg of 4.48 dm$^3$ carbon dioxide at STP.

• A. 2.2 $\times$ 10$^{-3}$ kg
• B. 4.4 $\times$ 10$^{-3}$ kg
• C. 6.6 $\times$ 10$^{-3}$ kg
• D. 8.8 $\times$ 10$^{-3}$ kg

Hint:

To calculate the mass of a gas, first calculate the moles using the molar volume at STP, then multiply by the molar mass. Don't forget to convert grams to kilograms if needed.

Answer 1

The Correct Option is B

At STP, 1 mole of any gas occupies 22.4 liters (22.4 dm$^3$). The molar mass of CO2 is 44 g/mol. First, calculate the number of moles in 4.48 dm$^3$ of CO2: \[ \text{Moles of CO}_2 = \frac{4.48 \, \text{dm}^3}{22.4 \, \text{dm}^3/\text{mol}} = 0.2 \, \text{mol} \] Now, calculate the mass of 0.2 moles of CO2: \[ \text{Mass} = 0.2 \, \text{mol} \times 44 \, \text{g/mol} = 8.8 \, \text{g} \] Finally, convert grams to kilograms: \[ \text{Mass in kg} = \frac{8.8 \, \text{g}}{1000} = 4.4 \times 10^{-3} \, \text{kg} \]