10 points which can happen during a physical change?

a) molecules can move more rapidly and freely and change states.
b) the molecules in a substance break into smaller molecules.
c) the molecules in a substance react with other molecules.
d) the molecules in a substance are destroyed.

i know it's not c or d, i'm not sure if b would count as a physical change or not.

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.)

Elements in group 2 are all called alkaline earth metals. what is most similar about the alkaline earth metals?

When water dissolves sugar, which process is not involved? o dissociation o hydration o surface area of the solute increases sa