De 570 PMark for Review
16 A large rock is motionless on a flat sidewalk. Which statement best explains why the rock remains
motionless?
F)
There are no forces acting on the rock.
The only force acting on the rock is directed toward the sidewalk.
H)
The forces acting on the rock are all balanced.
J)
The sidewalk exerts an unbalanced force on the rock.

Liquid ammonia is produced at high temperatures and under great pressure in a tank by passing a mixture of nitrogen gas and hydrogen gas over an iron catalyst. the reaction is represented by the following equation. n2(g) + 3h2(g) → 2nh3(g) changing all but one experimental condition will affect the amount of ammonia produced. that condition is a) increasing the concentration of both reactants b) changing the temperature within the tank c) decreasing the pressure within the tank. d) increasing only the amount of nitrogen present.