states of matter

Question 1

describe particles of the 3 states of matter

Answer 1

solid- densely packed, tight
liquid- looser, close together
gas- loosely packed, far apart

Question 2

describe forces of attraction between particles of the 3 states of matter

Answer 2

solid-strong forces of attraction (crystal lattice- regular rigid structure)
liquid- medium strength forces (lattice lost)
gas- weak strength forces of attraction between particles

Question 3

describe shape of the 3 states of matter

Answer 3

solid-regular rigid shape
liquid- fills shape of container from bottom up
gas-no fixed shape

Question 4

describe volume of the 3 states of matter

Answer 4

solid-fixed particles,close together
liquid-volume increases,particles further
gas-no fixed volume

Question 5

describe compressibility of the 3 states of matter

Answer 5

solid-incompressible
liquid- virtually incompressible
gas-compressible

Question 6

temperature

Answer 6

the temperature of an object is proportional to the average kinetic energy of its particles

Question 7

dependant variable

Answer 7

what we MEASURE , read off

Question 8

independent variable

Answer 8

independent variable-what we CHANGE /control/manipulate

Question 9

Melting point

Answer 9

the temperature at which a solid changes to a liquid

Question 10

Freezing point

Answer 10

the temperature at which a liquid changes to a solid

Question 11

Boiling point

Answer 11

the temperature at which a liquid changes to a gas or a gas changes
to a liquid

boiling - pressure of vapour in bubbles=atmospheric pressure in bubbles = atmospheric pressure

Question 12

boiling vs evaporation

Answer 12

boiling occurs throughout the substance whereas evaporation is a surface phenomenon

boiling occurs at particular temperature of a substance, whereas evaporation occurs at any temp

Question 13

water boiling point at dbn vs jhb

Answer 13

100 dbn
94-97 jhb

At a higher elevation, the lower atmospheric pressure means heated water reaches its boiling point more quickly—i.e., at a lower temperature.

Question 14

describe the cooling phase changes

Answer 14

liquid to solid - freezing
gas to liquid- condensation
gas to solid- deposition

Question 15

describe the heating phase changes

Answer 15

solid to liquid- melting
liquid to gas- boiling
solid to gas- sublimation

Question 16

precise

Answer 16

similar results - data points close together

because-few random errors

Question 17

accurate

Answer 17

desired result , outcome we want
ave close to true value

because-few errors in selection and use of apparatus.

Question 18

fair test

Answer 18

investigation where independent variable changed,other conditions kept same

Question 19

reliability

Answer 19

repeat at least 2 more times and calculate an average

Question 20

when do substances change phase

Answer 20

when temperature is increased or decreased

Question 21

evaporation

Answer 21

molecules w high kinetic energies move near surface moving fast enough to overcome forces of attraction and escape from liquid- forming vapour

particles less energetic- temp of remaining liquid drop (eg sweating -regulate body temp)

Question 22

energy during a HEATING phase change

Answer 22

constant Ek( temperature constant-still getting same energy (heat)- being used diff)

increase in Ep as change phase

constant temperature and phase change as forces between particles overcome(pull away from each -phase change)

Question 23

energy at rise in HEATING CURVE

Answer 23

Ek increasing as temperature increases (T proportional to Ek)

constant Ep (no phase change)

increase in temperature(particles move faster)

Question 24

Ep

Answer 24

potential energy

used to overcome forces holding particles together - phase change

Question 25

Energy during phase change COOLING

Answer 25

Rise

Ek decreasing (T proportional to Ek)
Ep constant
decrease in temp(particles move slower)

phase change
Ek constant. Ep decreases
constant temperature (forces between particles strengthened- move closer-phase change

Question 26

melting + freezing

Answer 26

substances melt and freeze at same temp