science midterm unit 1-3

Question 1

what are the 5 key things in the particle model of matter

Answer 1

1. All substances are made of tiny
   particles.
2. All particles in a pure substance are
   the same. Different pure substances
   are made of different particles.
3. The particles have spaces between
   them.
4. The particles are always in motion —
   vibrating, rotating, and (in liquids and
   gases) moving from place to place.
   The speed of the particles increases/
   decreases when the temperature
   increases/decreases.
5. The particles in a substance are
   attracted to one another. The strength
   of the attractive force depends on the
   type of particle.

Question 2

what is a solid

Answer 2

is the state of matter of a substance that has a definite shape
and volume (for example, a sugar cube).

Question 3

what is a liquid

Answer 3

is the state of matter of a substance that has a definite volume,
but no definite shape (for example, water).

Question 4

what is a gas

Answer 4

is the state of matter of a substance that has neither a definite
shape nor a definite volume (for example, oxygen).

Question 5

what is melting

Answer 5

when the physical state of a substance is
transformed into another state for example Vaporization, the change from a liquid to a gas, is another type of change of state.

Question 6

what is sublimation

Answer 6

is an unusual change of state that occurs when either a

solid turns into its gaseous state or a gas turn into a solid without becoming a liquid first.

Question 7

what is a homogenous mixture

Answer 7

is a mixture that only contains one type of particle such as paints