a group of students are wandering around a room. when their teacher claps, the students sit down wherever they are.

this situation best models the formation of which type of solid?
1) an amorphous solid because the particles do not have a regular structure
2) an amorphous solid because the motion of the particles stopped
3) a crystalline solid because the moving particles lock into fixed positions
4) a crystalline solid because the particles have a long-range order

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 .