Classify each of the following as either a physical change or a chemical change: a. tearing a sheet of paper

b. melting a piece of wax

c. burning a log

d. milk souring

What is the density of the black hole

Which real-world scenarios below represent physical and chemical changes? -running a car -exploding fireworks -mixing water and powdered drink mix -combining oil and vinegar to make salad dressing -taking aspirin for a headache -diluting bleach with water-digesting dinner-spreading peanut butter on bread

Nonpoint source pollution is difficult to control because it