Modern pennies are composed of zinc coated with copper. Student finds the mass of a penny to be 2.482 g and then makes several scratches in the copper coating (to expose the underlying zinc). The student puts the scratched penny in hydrochloric acid, where the subsequent reaction happens between the HCl and zinc (the copper remains undissolved):
Zn(s) + 2HCl(aq) --> H2(g) + ZnCl2(aq)
The student collects the hydrogen produced over water at 25 degrees Celsius. The collected gas occupies a volume of 0.899 Lat a total pressure of 791 mmHg. (Suppose that all theZn in the penny dissolves.)
What equation is used to find the amount of H2 gas provided the information from the question?