Achemical reaction, where more energy is released than is needed to get the reaction started, is called?

a)
a really amazing reaction

b)
endothermic

c)
exothermic

d)
non-reactive

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.