What is true of spontaneous reactions when thinking about chemical systems?
a. Reactions are always independent of temperature.
b. All reactions are all easily and substantially reversible.
c. They favor the formation of reactants.
d. Products may take many years to form.

Define a is a tiny pavket of energy

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 is the atomic number of a nucleus changed by alpha decay