What about energy can change and what does not change, according to the law?

Name the element in group 17, period 2. (periodic table)

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.

Δu of , in kj/kg, as it isto k, (a)as a of , (b) at , (c) at .