States of matter

Question 1

Describe the intermolecular forces, arrangement, motion, and compressibility of a solid

Answer 1

High intermolecular forces of attraction, tightly packed and regularly arranged, vibrate in fixed positions, incompressible

Question 2

Describe the intermolecular forces, arrangement, motion, and compressibility of a liquid

Answer 2

Intermediate intermolecular forces of attraction, closely packed and irregularly arranged, slide past each other, incompressible

Question 3

Describe the intermolecular forces, arrangement, motion, and compressibility of a gas

Answer 3

Very weak/non-existent intermolecular forces of attraction, far apart and irregularly arranged, quickly, randomly, freely moving in all directions, compressible

Question 4

Describe the 4 main changes in state

Answer 4

Melting: solid to liquid
Freezing: liquid to solid
Boiling/evaporation: liquid to gas
Condensation: gas to liquid

Question 5

What is sublimation

Answer 5

The direct change of a substance from solid to gas

Question 6

Explain how changes of state occur

Answer 6

As particles of a substance are heated, they gain kinetic energy move more and overcome attractive forces; when they are cooled, they lose kinetic energy and form attractive forces. When a certain temp. is reached the substance changes state

Question 7

What are melting and boiling points?

Answer 7

They are the temps. at which changes of state occur

Question 8

What is the difference between the melting and boiling points of pure and impure substances?

Answer 8

Pure substances: have sharp defined melting and boiling points
Impure substances: have a range of melting and boiling points (usually lower melting point and higher boiling point)