What must occur for a change to be a chemical reaction?
a.
There must be a change in chemical properties.
b.
There must be a change in physical properties.
c.
The change must involve a change in mass.
d.
The change must involve a change in volume.

Question

What must occur for a change to be a chemical reaction?
a.
There must be a change in chemical properties.
b.
There must be a change in physical properties.
c.
The change must involve a change in mass.
d.
The change must involve a change in volume.

anonymous · Answer

Think about it a change in physical properties would only be a change in state- solid, liguid, gas, you would be altering the distance of the molecules (reactants)  only- not changing them into producs. A change in mass is just reducing the number of molecules (reactants). However a chamical reaction could lead to a change in mass, but it is not because of it, this is the same for change in volume. It must be a. because chemical changes are occuring in the reactant molecules, i.e braking down and re-bonding into products.

anonymous · Answer

@AnImEfReaK is right . try to understand :)