molecules and matter

Question 1

density

Answer 1

mass per unit volume

Question 2

solid

Answer 2

particles vibrate in fixed positions
fixed shape

Question 3

liquid

Answer 3

particles are in contact but can move about at random
no fixed shape
can flow

Question 4

gas

Answer 4

particles far apart and move about at random
density of gas is much less than a solid or liquid
no fixed shape or volume

Question 5

solid- liquid

Answer 5

melting point

Question 6

liquid- solid

Answer 6

freezing point

Question 7

liquid- gas

Answer 7

boiling point

Question 8

gas- liquid

Answer 8

condensing

Question 9

latent heat

Answer 9

for a substance to change state, energy must be transferred to or from the substance

Question 10

internal energy

Answer 10

total energy in the kinetic energy store and potential energy store of the particles

Question 11

specific latent heat of fusion

Answer 11

energy needed to change 1kg of the substance from a solid to a liquid with no change in temperature

Question 12

specific latent heat of vaporisation

Answer 12

energy needed to change 1kg of the substance from a liquid to a vapor with no change in temperature

Question 13

pressure

Answer 13

total force from all the collisions produces a steady pressure on the walls of the container

Question 14

fixed mass of gas

Answer 14

number of gas molecules is constant
if temp of gas is constant, then average speed of molecules is constant

Question 14

volume of a fixed mass of gas is reduced

Answer 14

molecules have less space to move in so they dont travel so far between collisions
number of collisions per second increases