State the phenomena shown by the pictures below.​

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.

Which scenario is most similar to the type of collision that gas particles have according to kinetic molecular theory

What is the percentage of hydrogen in c2h4