9.60 g of a gas X occupies the same volume at 0.30 g of hydrogen under the same conditions. Calculate the molar mass of X [H = 1]
- 8g mol -1
- 16 gmol -1
- 32g mol -1
-
64g mol -1
The correct answer is: D
Explanation
Using the ideal gas equation,
PV = nRT.
where \(n = \frac{mass}{\text{molar mass}}\).
For Hydrogen, \(\frac{m_H}{M_H} = \frac{PV}{RT}\).
For element X, \(\frac{m_X}{M_X} = \frac{PV}{RT}\)
Under the same conditions implies \(\frac{PV}{RT}\) is the same for both hydrogen and X.
\(\frac{m_H}{M_H} = \frac{m_X}{M_X}\)
Molar mass of X = \(\frac{\text{molar mass of hydrogen} \times \text{mass of X}}{\text{mass of hydrogen}}\)
= \(\frac{2 \times 9.6}{0.3}\)
= 64 g/mol