Question

g A sample that contains aluminum is reacted with sulfuric acid according to the equation given below. When the aluminum dissolved 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: Mass of hydrogen gas is collected is 0.058 grams

Explanation:

The balanced chemical reaction is :

$2Al+3H_2SO_4\rightarrow Al_2(SO_4)_3+3H_2$

According to the ideal gas equation:

PV=nRT

P = Pressure of the gas = 739 mm Hg =  0.97 atm   (760mmHg= 1atm)

V= Volume of the gas = 0.722 L

n=  moles of gas = ?

T= Temperature of the gas in kelvin =$25^0C=(25+273)K=298K$

R= Gas constant =$0.0821Latm/Kmol$

$0.97\times 0.722=n\times 0.0821\times 298$

n=0.029

Mass of hydrogen =$moles\times {\text {Molar mass}}=0.029mol\times 2g/mol=0.058g$

Mass of hydrogen gas is collected is 0.058 grams