(Q012) Mafic minerals a. form rhyolite and granite. b. crystallize at a higher temperature than do silicic minerals. c. typically crystallize last out of a melt. d. are rich in aluminum and sodium.

Use examples from the article to explain one positive and one negative effect that chemistry has had on society.

Voltaic cells produce a positive overall charge. what does this indicate? a. the reaction is likely to be endothermic. b. the reaction is spontaneous. c. the reaction is not likely to occur. d. the reaction is not spontaneous.

13. a covalent bond between two atoms is likely to be polar if: a. one of the atoms is much more electronegative than the other. b. the two atoms are equally electronegative. c. the two atoms are of the same element. d. the bond is part of a tetrahedrally shaped molecule. e. one atom is an anion.