P3 topic 5

Question 1

pressure law

Answer 1

States that the pressure exerted by a fixed mass of gas, kept at a constant volume, is directly proportional to its temp on the Kelvin scale

Question 2

which unit of temp should you always use for calculations involving the gas laws?

Answer 2

kelvin

Question 3

what are the three gas laws?

Answer 3

Boyle’s law; Charles’ law; the pressure law

Question 4

what is atmospheric pressure caused by?

Answer 4

air molecules colliding with every surface

Question 5

what can pascals also be written as?

Answer 5

Newton per square metre

Question 6

what is atmospheric pressure?

Answer 6

100 000 Pa

Question 7

Boyle’s law

Answer 7

the pressure exerted by a fixed mass of gas at constant temp is inversely proportional to its volume

Question 8

Charles’ law

Answer 8

the volume V occupied by a fixed mass of gas kept at constant pressure it directly proportional to its temperature

Question 9

how can Charles’ law be investigated?

Answer 9

using a syringe with its nozzle sealed- the syringe full of gas can be immersed in some boiling water- as the water cools, the temp and vol of gas can be recorded and used to plot a graph- the graph shows a straight line and can be extrapolated back to show that at absolute zero, vol of gas is theoretically 0

Question 10

kinetic theory of matter

Answer 10

describes the behaviour of the 3 states of matter in terms of the movement of particles; explains how the average KE of particles is related to temp; explains why gases exert pressure

Question 11

solid

Answer 11

regular pattern of particles; particles are v close together; particles vibrate around fixed positive; as temp increases they vibrate more quickly

Question 12

liquid

Answer 12

random arrangement of particles; particles are close together; particles move around each other; as temp increases, average speed increases

Question 13

gas

Answer 13

random arrangement of particles; on average the particles are far apart; particles move quickly in all directions and have a variety of speeds (random motion)

Question 14

what happens at absolute zero?

Answer 14

all particles of substance stop moving and have step kinetic energy

Question 15

absolute zero

Answer 15

0 K

Question 16

what is absolute zero the same as?

Answer 16

-273 degrees Celsius

Question 17

what do you do to convert temp in degrees Celsius to K?

Answer 17

add 273

Question 18

how do you convert temp in K to temp in degrees Celsius?

Answer 18

subtract 273

Question 19

what happens when heat energy is supplied to a gas?

Answer 19

the particles move faster and therefore collide more frequently with each other and the sides of the container- average KE per particle increased and this increases the total KE of the gas

Question 20

what is the temp of a gas in K proportional to?

Answer 20

tbd average KE of the particles

Question 21

why does pressure if a gas increase with temperature?

Answer 21

as the temperature of a gas increases, the molecules’ speed increases- the molecules collide w each other and the walls more frequently- this causes the force and therefore the pressure on the walls to increase