12. Identify the following as a chemical or physical change: Chemical
a. Burning paper
b. Forming new compounds
C. Baking a cake
d. Acid rain reacting with rocks
e. Change in size
f. Change in color Chemical
8. Slicing bread
h. Change in size but not the substance
1. Producing heat
Water rushing over rocks
k. Tearing paper

Construct the hypothetical phase diagram for metals a and b between room temperature (20c) and 700c, given the following information: * the melting temperature of metal a is 480c. • the maximum solubility of b in a is 4 wt% b, which occurs at 420c. • the solubility of b in a at room temperature is 0 wt% b. • one eutectic occurs at 420c and 18 wt% b–82 wt% a. • a second eutectic occurs at 475c and 42 wt% b–58 wt% a. • the intermetallic compound ab exists at a composition of 30 wt% b–70 wt% a, and melts congruently at 525c.• the melting temperature of metal b is 600c. • the maximum solubility of a in b is 13 wt% a, which occurs at 475c. • the solubility of a in b at room temperature is 3 wt% a.

Which of the following would be an accurate picture of the earth during the summer time of the northern hemisphere?

Is a pencil falling to the floor anon contact force, a force, or a contact force