Gas laws

Question 1

Describe the structure of gas particle

Answer 1

Gas particles in a container are spaced out and move randomly, these particles will bump against each other and the container, when they hit the wall pressure is generated

Question 2

Describe what happens to gas particles when it is heated

Answer 2

Gas particles move faster and more randomly, there are more frequent collisions, generating more pressure, causes pressure to increase as volume of gas decreases

Question 3

what is total pressure?

Answer 3

the sum of all collision forces exerted, the more collision the greater the pressure

Question 4

Define Charles’ law

Answer 4

for a fixed mass of gas at constant pressure, the volume is directly proportional to the temperature

Question 5

Define Boyle’s law

Answer 5

PxV=constant
If pressure increases, volume decreases
For a fixed mass of gas, the product of a volume of gas and pressure are always the same providing temperature is constant
decreasing volume, increases pressure

Question 6

Boyle’s law equations

Answer 6

PxV=constant
p1v1=p2v2

Question 7

Define the order of the atmosphere

Answer 7

1. troposphere (closest to earth) 0-12km
2. stratosphere 12-50km
3. mesophere 50-80km
4. thermosphere 80-700km
5. exosphere 700-10,000km

Question 8

What occurs to volume of gas during exhalation?

Answer 8

Volume decreases as gas cools as it leaves the body, as volume is proportional to temperature

Question 9

What is air pressure in atm measured in?

Answer 9

kPa/mmHg (BP)

Question 10

What is air pressure known as? and what is it at sea level?

Answer 10

Barometric pressure
101kPa

Question 11

Where is atm pressure the greatest?

Answer 11

it is greatest closest to the earth surface, pressure decreases as altitude rises

Question 12

Conversion of Kpa to mmHg

Answer 12

1kPa=7.5mmHg

Question 13

conversion of 1mmHg to kPa

Answer 13

1mmHg=0.133Kpa
e.g., 750mmHg x 0.133=99.75kPa

Question 14

Define the composistion of air

Answer 14

N=78.0%
O= 20.9%
Ar=0.9%
CO2=0.04%
other gases 0.17%

Question 15

Define Dalton’s law

Answer 15

The total pressure of a mixture of gases is equal to the sum of the partial pressures that each gas would exert in isolation

Question 16

Partial pressure calculation

Answer 16

partial pressure= % of gas x atm pressure

Question 17

Calculate partial pressure of oxygen in atm pressure

Answer 17

20.9x101=21.109kPa

Question 18

factors affecting movement of gases

Answer 18

Concentration gradient
temperature
solubility of gas in liquid

Question 19

Define diffusion

Answer 19

the net movement of a group of particles from an area of high concentration to an area of low concentration. Diffusion increases with temp and a steep conc gradient

Question 20

Partial pressure gas movements

Answer 20

Gases will equalize, from high to low, The speed in which gases move depends on partial pressure difference, the larger the pressure gradient the faster gas particles will travel

Question 21

Define Henry’s law

Answer 21

This law states that the number of molecules dissolving in a liquid is proportional to the partial pressure at the surface of the gas

Question 22

Henry’s law equation

Answer 22

P=KH.C
P= partial pressure
Kh= henry’s law constant, dependant on solute, solution and temp
C=concentration of dissolved gas

Question 23

What occurs to pressure in high altitude

Answer 23

as you ascend air pressure decreases, e.g., pressure at Everest is 33kPa
partial pressure of O2 also decreases

Question 24

What is partial pressure of O2 at everest

Answer 24

P=20.9x33kpa
=6.897kPa

Question 25

What is water vapour pressure?

Answer 25

the water vapour pressure is exerted by water molecules in gaseous form

Question 26

Partial pressure of water equation at body temp (37c)

Answer 26

6.3kPa

Question 27

Partial pressure of moist inspired oxygen equation

Answer 27

is 20.9x (101-6.3kPa) (atm P)
20.9x94.7=19.8kPa