Galena is a mineral that creates smooth, flat surfaces when it breaks. It is a 2.5 on Mohs scale. Galena . A)has cleavage and is soft
B)has fracture and is very hard
C)has fracture and a shiny luster
D)has cleavage and no streak

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.

Match the formula for the following compound:   magnesium sulfate heptahydratemgs·7h2omg2so4·7h2omg(so4)2·7h2omgso4·7h2o

When a beta particle is emitted, the mass number of the nucleus a. decreases by one b. increases by one c. remains the same d. decreases by two