Equilibrium is characterized by 1. opposing processes occurring at equal rates
2. an open system
3. net change in amount of substance in one phase
4. changes in physical states

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.)

How much heat is added if 0.814g of water increase in temperature by 0.351 degree c?

Nthis lab, you will do experiments to identify types of changes. using the question format you learned (shown above), write an investigative question that you can answer by doing these experiments