Need Help Asap. Could someone explain this to me

21. What is the maximum number of moles of H2O that can be produced from the reaction of 5.6 mol H2 and 4.7 mol O2?

H2 + O2 = H2O

What is the limiting reactant?
What is the excess reactant?

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

What are the major types of a chemical compound

What mass of glucose is produced when 54g of water react with carbon dioxide