1. particles in a gas are best described as
• slow-moving, kinetic, hard spheres
• small, hard spheres with insignificant volumes
2. how does the atmospheric pressure at altitudes below sea level compare with atmospheric pressure at sea level?
• the atmospheric pressure below sea level is higher.
3. when a gas is heated,
• some of the absorbed energy is converted to potential energy, and some is converted to kinetic energy
• none of the energy is converted to kinetic energy
4. why does a liquid's rate of evaporation increase when the liquid is heated?
• more molecules have enough energy to overcome the attractive forces holding them in the liquid.
• the average kinetic energy of the liquid decreases.
5. crystals are characterized by particular patterns that repeat in how many dimensions?
• three dimensions only
• the patterns do not repeat.
6. compared to the melting points of ionic compounds, the melting points of molecular solids tend to be
• lower
• higher

1) small, hard spheres with insignificant volumes

2)The atmospheric pressure below sea level is higher.

3) some of the absorbed energy is converted to potential energy, and some is converted to kinetic energy

4)More molecules have enough energy to overcome the attractive forces holding them in the liquid.

5)three dimensions only

6) lower

Explanation:

1. The particles of gas are small, hard spheres with insignificant volumes. they are not slow moving.

2. Due to more air weight  below sea level compare with at sea level, the atmospheric pressure is more below sea level, the pressure decreases with increase in altitude.

3. On heating gas molecules, they gain energy. This energy is being converted to potential energy and some of it to kinetic energy. It increases the speed of gas molecules.

4. The evaporation occur when a liquid gains sufficient energy to overcome the inter molecular attractions and escape from the surface of liquid.

5. The patterns repeat in all the three dimensions.

6. Due to stronger inter molecular interactions in ionic compounds, they have higher melting points than molecular solids.

it is the most commonly accepted one