Which of the following is a physical change? a. burning a piece of wood b. sawing a piece of wood in half c. rust forming on an iron fence d. a copper roof changing color from orange to green

1. calculate the approximate enthalpy of the reaction in joules. estimate that 1.0 ml of vinegar has the same thermal mass as 1.0 ml of water. iqnore the thermal mass of th sodium bicarbonate. note: it takes about 4.2 joules () to change 1.0 gram (1.0ml) of water 1.0 c

Fission of uranium-235 products energy and a. isotopes of smaller elements b. isotopes of larger elements c. lighter isotopes of uranium d. heavier isotopes of uranium

Which reason best explains why metals are malleable? a)because they have delocalized electrons b)because they have localized electrons c)because they have ionic bonds d)because they have rigid bonds