Im in the middle of a chem test and i literally have no clue what is happening

0.2348 grams of pbcl2 used to form 44.0 ml of solution.

How will the volume of a gas be affected if the pressure is tripled, but the temperature remains the same?

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 .