What is the rate of forward and reverse reactions

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.

What are the chemical names of these compounds? ke: mg3n2: reset next

Explain in detail of the four major scientific developments that spurred the formulation of the plate tectonics theory