Hypothesis 2 (Particle size): If you
the particle size of a reactant, then the reaction rate
will increase because of the reactant's surface area is exposed allowing more particles to make
contact with each other

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

particle   p is an electron and particle q is a neutron

the answer to this question is 3.