n-Butyl phthalate is used as an insect repellant and is composed of carbon, hydrogen and oxygen. When a 0.3413 g sample was subjected to combustion analysis, 0.2430 g of water and 0.8633 g of carbon dioxide is produced. In another analysis, the molecular weight was determeined to be 278.38 g/mol Calculate the empirical forumla and molecular formula Also provide some important highlights, which was discussed in class, on how you solve this problem. If stoichiometry is involved be sure to draw the stoichiometry maps associated with the problem

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.)