8A.4 Ideal Gas Behaviour

Question 1

what is Boyle’s law

Answer 1

for a constant mass of gas at room temperature, the pressure exerted by the gas is inversely proportional to the volume it occupies

Question 2

how can you investigate Boyle’s law

Answer 2

set up a glass column and fill with inert liquid and attach it to a pressure tube thingy, then take measurement of the length of air which is trapped by the liquid (the length = volume of gas) at different pressures then plot a pressure against 1/length to get a straight line (look at page 125)

Question 3

pressure is measured by

Answer 3

barometer

Question 4

what safety precautions should you take before investigating Boyle’s law

Answer 4

1. wear eye protection
2. make sure all the connection are secure to avoid high pressure leaks
3. reduce the pressure before disconnecting the pump

Question 5

what is Charles’s law

Answer 5

for a constant mass of gas at a constant pressure, the volume occupied by the gas is proportional to its absolute temperature.

Question 5

what is the pressure law

Answer 5

for a constant mass of gas at a constant volume, the pressure exerted by a gas is proportional to its absolute temperature

Question 6

how do we investigate pressure law

Answer 6

get a beaker filled with water and but a flask attached to a pressure pump into the water and heat is using a Bunsen burner measure the pressure at different temps (by a thermometer) and plot a pressure x temp to get a straight line (note pressure and temp can be taken by electronic signals and the data logged by an attached computer

Question 7

what safety precautions should we take when investigating pressures law

Answer 7

1. Wear eye protection
2. make sure the water in the beaker doesn’t get too low

Question 8

the 3 gas laws are what type of laws

Answer 8

empirical laws ( meaning they are worked out from experimental data like staright line best fit

Question 9

the 3 gas laws are what type of laws

Answer 9

empirical laws (meaning they are worked out from experimental data like straight line best fit)

Question 10

what holes is in Charles’s law

Answer 10

the law states that at zero absolute temp, the volume of the gas would be zero - it would disappear, but that doesn’t happen since the gas volume cannot reduce to less than the combined volume of its molecules

Question 11

the 3 gases law are

Answer 11

idealized meaning they are mainly accurate for ideal gases

Question 12

what properties does an ideal gas have

Answer 12

1. the molecules have negligible size
2. the molecules are identical
3. all collision are perfectly elastic and the time of collision is significantly smaller than the time between collisions
4. the molecules exert no force on each other, except during collisions
5. there are enough molecules so that statistics can be applies
6. the motion of molecules is random

Question 13

what is an ideal gas

Answer 13

its a theoretical gas which does not suffer from the real world difficulties meaning real gases do not perfectly follow the gas law

Question 14

what is equation of the state

Answer 14

the single equation that defines gas in terms of volume, pressure, temp, and quantity pV =NKT and for large quantities of gas pV= nRT

Question 15

what is the mole

Answer 15

an SI unit for the amount of substance. one mole contains 6.02 x 10^23 molecules of the substance

Question 16

by comparing 1 mole of an ideal gas wiht the equation of state we get

Answer 16

Na x K = 8.31

Question 17

what is an alternative equation for kinetic theory of gases

Answer 17

pV = 1/3 Nm<c^2> (derivation and everything else page 127)