Sthis equation balanced and in the lowest form? 4nh3 → 2n2 + 6h2

Can someone me with questions 15 to 17 plz.

Compare and contrast physical changes with chemical changes.

Which sentence about particles in matter is true? a. atoms are present in solids and liquids but not in gases. b. the particles of matter are in constant motion. c. the same kinds of atoms are found in different elements. d. when a solid changes to a liquid, the sizes of the particles change.