1. Suppose the mechanical advantage of a machine is 4, and the input force is 20 N. What is the output force?
0 16 N
0 24 N
80 N
O5N

State one important difference between a physical change and a chemical change?

Nitric acid can be formed in two steps from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming natural gas. in the first step, nitrogen and hydrogen react to form ammonia: (g) (g) (g) in the second step, ammonia and oxygen react to form nitric acid and water: (g) (g) (g) (g) calculate the net change in enthalpy for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen from these reactions. round your answer to the nearest .

Arrange the elements in order of increasing electronegativity. use the periodic table to you arrange the elements. p o k mg