1. Total U.S. farmland occupies 954 million acres. 单位换算题
(1)How many square miles is this?__ (1 acre = 43,560 ft^2, 1 mile = 5280 ft).
(2)Total U.S. land area is 3.537 million square miles. What percentage of U.S. land is farmland?__
2. Classify each of the following as a law or a theory.分类题
(a) Chlorine is a highly reactive gas.
(b) If elements are listed in order of increasing mass of their atoms, their chemical reactivity follows a repeating pattern.
(c) Neon is an inert (or nonreactive) gas.
(d) The reactivity of elements depends on the arrangement of their electrons.
Law____Theory____
