Modern pennies are composed of zinc coated with copper. A studentdetermines the mass of a penny to be 2.482 g and then makes severalscratches in the copper coating (toexpose the underlying zinc).The student puts the scratched penny in hydrochloric acid, wherethe following reaction occurs between the zinc and the HCl (thecopperremains undissolved):
Zn(s)+2HCl(aq) –> H2(g)+ ZnCl2(aq)
The student collects the hydrogen produced over water at25 degrees Celcius. The collected gas occupies a volume of 0.899 Lat a total pressure of 791mmHg.(Assume that all theZn in the penny dissolves.)
What effect does the fact that the hydrogen gas wascollected over water @ 25 degrees Celcius at a total pressure of791 mmHg have on the calculation ofthe amount of H2 gasproduced?