Question

Typically, the hydrogen gas is bubbled through water for col- lection and becomes saturated with water vapor. Suppose 240. mL of hydrogen gas is collected at 30.8C and has a total pressure of 1.032 atm by this process. What is the partial pressure of hydrogen gas in the sample? How many grams of zinc must have reacted to produce this quantity of hydrogen?

Answer 1

Answer:PH2=0.994atm, mass of zinc=0.606g

Explanation:

Equation for the reaction is written as;

Zn(s) + 2HCl(aq) - ZnCl2(aq) + H2(g)

V= 240ml = 0.240L

T= 30.8oC = 303.8K

Ptotal= 1.036atm

Pwater = 32mmHg at 30oC = 0.042atm

Therefore

PH2 = Ptotal - Pwater

= 1.036-0.042atm

=0.994atm

But PV= nRT

n = PV/RT

= 0.994x0.240/0.0821x303.8

= 0.24/24.94

=0.009324moles

For the grams of zinc

n=mass in grams/molar mass

Mass in grams = no of moles x molar mass

=0.009324x65 = 0.606g