Question

Which situation describes evidence of a chemical change?

A. When food color is added to water, it changes color.
B. A solid changes into liquid when heated.
C. A solution feels warm after a cool solid is added to it.
D. A cloudy solution is clear after filtering.

Answer 1

The correct answer is:

A solution feels warm after a cool solid is added to it (C)

Step-by-step explanation:

Chemical changes among other results in a change of the temperature of the reactants, producing a product of higher temperature (exothermic reaction) or a product of lower temperature (endothermic reaction). In this case, the temperature of the product was higher than the reactants suggesting an exothermic reaction.

The other options however, suggests physical changes rather than a chemical changes;

A. the change of color of the water suggest mixing or water and color molecules.

B. solid changing into liquid is change of state, which is more of a physical change than chemical

D. Filtration is a physical process, hence the change is a physical change.