A change that produces matter with a different composition is a change.

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

Areaction is first order with respect to reactant x and second order with respect to reactant y. which statement describes the rate law for this reaction?

What conclusion can you draw from this experiment about the components of the black ink?