Explain the changes in kinetic energy as a substance is heated to its melting point, and how these changes affect intermolecular forces during the heating process.

The more solid a substance is, the less kinetic energy there is. This is because there is not a lot of space for the atoms in the solid state to move. However, in the gaseous state, the atoms are far apart with plenty of space, this lets them create a lot more kinetic energy. Solids have a lot more intermolecular forces because the atoms are together. The IMF (intermolecular force) is what lets the atoms/molecules stick together. In the solid state, all the atoms are stuck together with little to no room in between. In the liquid state, it has a lot of IMF but is weaker then the IMF in the solid state. This is why you have so much resistance when you try to move through water. In the gaseous state, there is little to no IMF because the atoms are all so far apart. This makes it easier for everyone to move around.

To answer your question more directly: As the substance is heated to its melting point, there is an increase in kinetic energy, but decrease in intermolecular forces.

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.

i think the answer is terrae but not 100 percent sure. ▓▬▬ §