V 12 > A À BI U ON AVA Ev Eva Indicate whether the statement is true or false. 1. It is easier to carry out a controlled experiment in the field than it is in the laboratory. (Pages 90-94) a. True b. Fals e 2. Plants utilize a portion of their gross primary productivity (GPP) for cellular respiration. (78-81) a. True b. Fals е 3. Lightning is one of the natural mechanisms by which atmospheric nitrogen is converted to ammonia or ammonium ions. (Pages 82-90) a. True b. Fals e

Which function is performed by earths atmosphere? a. ultraviolet rays are prevented from reaching the ozone layer. b. earths temperature is raised and moderated by trapping in heat c. charged particles from the sun are prevented from reaching earth. d. magnetic charges from space are prevented from reaching earths surface.

Calculate the number of kilojoules to warm 125 g of iron from 23.5°c to 78.0°c.

Many free radicals combine to form molecules that do not contain any unpaired electrons. the driving force for the radical–radical combination reaction is the formation of a new electron‑pair bond. consider the chemical equation. n(g)+no(g)⟶nno(g) n(g)+no(g)⟶nno(g) write lewis formulas for the reactant and product species in the chemical equation. include nonbonding electrons. n(g)n(g) select draw rings more erase select draw rings more erase select draw rings more erase n no(g)