Question

A change in _____ means that a chemical reaction has occurred.
A) the energy and mass
B) the kinds of atoms involved
C) the properties and identity of the reacting substances
D) the energy and kinds of atoms of the reacting substances

Answer 1

From Google:

In a chemical change, the atoms in the reactants rearrange themselves and bond together differently to form one or more new products with different characteristics than the reactants. When a new substance is formed, the change is called a chemical change.

Answer 2

C) the properties and identity of the reacting substances

Answer 3

___ can change as a chemical reaction occurs

Answer 4

increase reaction rate

Answer 5

Increasing the concentration of the reactants will increase the frequency of collisions between the two reactants. When collisions occur, they do not always result in a reaction (atoms misaligned or insufficient energy, etc.). Higher concentrations mean more collisions and more opportunities for reaction.