A combination of substances that are held together by physical rather than chemical ties is called a:

What type of change occurs when ice melts and becomes water?

If a product has a pH of 8.9, it is considered:

A specific type of oil used in nail polish dryers and as a skin protectant is:

There are about ______ naturally occurring elements, each with its own distinctive physical and chemical properties.

Pure water with a pH of 7 is considered to be:

The separating of a substance into ions is known as ________