A sample of hydrogen is collected over water at in a flask

CHEMISTRY · Single correct · A Level · Chemistry · Amount of substance · Amount of substance

Problem

A sample of hydrogen is collected over water at

25^{\circ}\text{C}

in a

250.0\,\text{mL}

flask. The barometric pressure is

755\,\text{mmHg}

, and the vapor pressure of water at

25^{\circ}\text{C}

24\,\text{mmHg}

. What amount of hydrogen, in moles, is present in the flask? (a)

1.02 \times 10^{-2}\,\text{mol}

(b)

1.05 \times 10^{-2}\,\text{mol}

(c)

9.8 \times 10^{-3}\,\text{mol}

(d)

1.15 \times 10^{-2}\,\text{mol}