PLZ HELP A group of students simulates colliding air masses. Using an index card for separation, a jar of warm tap water with red food coloring is placed over a jar of cold water with yellow food coloring. The index card that separates the two bodies of water is removed. Students observe how the two fronts travel in relation to one another.

A.) Air masses are not distinguisable by color.

B.) Air masses are neither hot nor cold in temperature

C.) Air masses do not collide in real life

D.) Air masses cannot be modeled

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.)