States of Matter

Question 1

Define boiling:

Answer 1

The process in which a liquid changes to a gas. It takes place inside a liquid and occurs at a fixed temperature.

Question 2

Define evaporation:

Answer 2

The process in which a liquid changes to a gas. It takes place at the surface of a liquid and occurs at a temperature below that of the boiling point.

Question 3

What is the latent heat of fusion?

Answer 3

The amount of energy required to change solids to liquids at its melting point.

Question 4

What is the latent heat of evaporation?

Answer 4

The amount of energy required to change a liquid to gas at its boiling point.

Question 5

Define diffusion:

Answer 5

The random movement of particles in all directions to fill the available space, moving down a concentration gradient. The diffusion rate is fastest in gases and slowest in solids.

Question 6

Factors affecting diffusion:

Answer 6

• Temperature: the rate of diffusion is directly proportional to temperature
• Particle mass: lighter particles move faster than heavier particles

Question 7

Example of experimental evidence of diffusion:

Answer 7

NH3 +HCl = ammonium chloride
When NH3+ reacts with HCl, dense white fumes are produced.
If one places a cotton soaked in NH3 on one side of a tube and a cotton soaked in HCl in the other side, dense white fumes will appear near the HCl-soaked cotton. This is because ammonia is lighter, so it diffuses faster.

Question 8

4 points of Kinetic Particle Theory:

Answer 8

• all matter is made of tiny, discrete particles
• the particles are in constant motion
• the kinetic energy of a particle changes with temperature
• the average kinetic energy of all particles is directly proportional to the absolute temperature