Study the triangle. What can you condude about
the angle measures?

What are the spectator ions in 2h+ + so42- + ca2+ + 2r → caso4 + 2h+ + 21?

Compare and contrast the bohr model and the electron cloud models of the atom.

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.