Which product (if any) will form a precipitate in the following reaction? K2SO4(aq) + Pb(NO3)2(aq) --> 2KNO3 + PbSO4

a. K2SO4
b. PbSO4
c. KNO3
d. No Precipitate formed

Compare and contrast physical changes with chemical changes.

How many protons, electrons, and neutrons are in each of the following isotopes? a. zirconium-90 b. palladium-108 c. bromine-81 d. antimony-123

Quickly what are the following of organisms that existed over a wide area but only for a limited time period called a.soft fossils b.mold fossils c.index fossils d.trace fossils