2000 - WAEC Chemistry Past Questions and Answers - page 2

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 = \(\frac{\text{molar mass of hydrogen} \times \text{mass of X}}{\text{mass of hydrogen}}\)

= \(\frac{1 \times 9.6}{0.3}\)

= 32 g/mol