A helium-filled balloon has a volume of 2.48 L and a pressure of 150 kPa. The volume of the balloon increases to 2.98 L after you climb up a very steep mountain with this balloon. (Temperature is kept constant). Be sure to answer both parts A and B. A. What is the new pressure of the helium gas? (For full credit, write the appropriate gas law formula, list the givens in the problem, indicate what the unknown is, and give your calculated answer). B. Use the kinetic molecular theory to explain why the volume of the gas changed in this scenario.

n2(g) + 3h2-> 2nh3(g)   this is the balanced equation

note the mole ratio between n2, h2 and nh3.   it is 1 : 3 : 2   this will be important.

moles n2 present = 28.0 g n2 x 1 mole n2/28 g = 1 mole n2 present

moles h2 present = 25.0 g h2 x 1 mole h2/2 g = 12.5 moles h2 present

based on mole ratio, n2 is limiting in this situation because there is more than enough h2 but not enough n2.

moles nh3 that can be produced = 1 mole n2 x 2 moles nh3/mole n2 = 2 moles nh3 can be produced

grams of nh3 that can be produced = 2 moles nh3 x 17 g/mole = 34 grams of nh3 can be produced

note:   the key to this problem is recognizing that n2 is limiting, and therefore limits how much nh3 can be produced.

answer; talc and gypsum;

6.4 cm (max) - 25 cm (min)