C5 - The Earths reasources and Chemical Analysis

Question 1

what percent of the worlds atmosphere is nitrogen

Answer 1

78%

Question 2

what percent of the worlds atmosphere is oxygen

Answer 2

21%

Question 3

what percent of the worlds atmosphere is water vapour

Answer 3

<1%

Question 4

what percent of the worlds atmosphere is carbon dioxide

Answer 4

<1%

Question 5

what percent of the worlds atmosphere is argon

Answer 5

<1%

Question 6

name three greenhouse gases

Answer 6

• methane
• carbon dioxide
• water

Question 7

what gases are believed to have been released from volcanoes during the first billion years

Answer 7

• carbon dioxide
• nitrogen
• water vapour
• ammonia

Question 8

there are theories about the earths early atmosphere have changed over time. why?

Answer 8

there is little evidence left as earth formed 4.6 billion years ago

Question 9

what are the effects of polar ice caps melting

Answer 9

rising sea levels which leads to less land avalable for housing

Question 10

what are the effects of warming seas

Answer 10

coral reefs dying which leads to reduction in aquatic biodiversity

Question 11

what are the effetcs of more frequent and extreme wether events

Answer 11

• global food shortage
• risk to human life

Question 12

exaplain how the interaction between short and long wavelenth interaction with matter creates the greenhouse effect

Answer 12

• short wavelength radiation from the sun is absorbed by the earth
• the earth re-emits longer wavelength radiation which is absorbed and reflected back to earth by greenhouse gases

Question 13

what are human activites that increase green house gases in the atmosphere

Answer 13

methane:
- cattle farming
- landfill
- rice plantations

carbon dioxide:
- burning fossil fuels
- deforestation

Question 14

what is pure water

Answer 14

solely made up of H2O molecules, all partilces are the same

Question 15

what is potable water

Answer 15

Water that is safe for humans to drink

Question 16

what is a finite reasource

Answer 16

A finite resource is one which will eventually run out as it is being used up at a faster rate than it can be replaced.

Question 17

what is an renewable reasource

Answer 17

Renewable resources are ones which are not going to run out

Question 18

what is the test for hydrogen

Answer 18

Test gas with a lighted splint.

Observation: A lighted splint “pops”.

Reason: Hydrogen burns rapidly - the “pop” is a small explosion.

Question 19

what is the test for carbon dioxide

Answer 19

Bubble gas through limewater.

Observation: Limewater turns cloudy/milky.

Reason: Insoluble calcium carbonate is formed.

Question 20

what is the test for oxygen

Answer 20

Test gas with a glowing splint.

Observation: A glowing splint re-lights.

Reason: The concentration of oxygen is mugh higher than in air so the splint can re-light.

Question 21

what is the test for chlorine

Answer 21

Test with damp blue litmus paper.

Observation: Litmus paper goes white (it is bleached)

Reason: Chlorine is a bleach

Question 22

in chromatography what is a stationary phase

Answer 22

• Does not move
• Attracts certain chemicals
• Usually paper

Question 23

in chormatography what is a mobile phase

Answer 23

• Does move
• Chemicals must be soluble in it
• Often water

Question 24

how do we calculate the Rf value

Answer 24

Rf = distance travelled by component / distance travelled by solvent

Question 25

what is a mixture

Answer 25

contains different particles

Question 26

what is an element

Answer 26

substance only made from one type of atom

Question 27

what is a compound

Answer 27

Substance made from different types of atoms joined together

Question 28

how do we know if a substance is pure

Answer 28

• Pure substances have fixed melting and boiling points eg. pure water melts at 0 °C and boils at 100 °C.
  -Pure substances always have a fixed, single melting and boiling point.

Question 29

how do we know if a substance is impure

Answer 29

Impure substances melt and boil over a range of temperatures

Question 30

what is a formulation

Answer 30

Many consumer products are not pure substances. They are a carefully designed mixture of substances known as a formulation.