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]
-
A.
8g mol -1 -
B.
16 gmol -1 -
C.
32g mol -1 -
D.
64g mol -1
Correct Answer: Option C
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{1 times 9.6}{0.3})
= 32 g/mol