Question

A sample that contains aluminum is reacted with sulfuric acid according to the equation given below. When the aluminum dissolves the total volume of gas collected over water at 25 °C is 0.722 L at a total pressure of 739 mm Hg. What mass of hydrogen gas is collected?

Answer 1

Answer:

$m_{H_2}=0.0574gH_2$

Explanation:

Hello,

In this case, the information about the pressure, volume and temperature are enough to compute the mass of hydrogen assuming its ideal behavior:

$n_{H_2}=\frac{PV}{RT}=\frac{739mmHg*\frac{1atm}{760mmHg}*0.722 L}{0.082 \frac{atm*L}{mol*K}*298.15K} =0.0287molH_2$

The mass is:

$m_{H_2}=0.0287molH_2*\frac{2gH_2}{1molH_2} \\m_{H_2}=0.0574gH_2$

Best regards.