C1

Question 0

What are Thermochromic pigments?

Answer 0

-They change colour when they are heated or cooled

• Used for:
  >mood rings
  >kettles
  >toys

Question 1

What are Phosphorescent Pigments?

Answer 1

They:

• glow in the dark
• absorb and store energy
• can be added to acrylic paints

Question 2

What are colloids made of?

Answer 2

• They are made of small, solid particles that are mixed well, with liquid particles

Question 3

What is a solute?

Answer 3

• A substance which gets dissolved

Question 4

What is a solvent?

Answer 4

• A liquid in which a substance is dissolved

Question 5

What are Insoluble substances?

Answer 5

• Substances that don’t dissolve in a liquid

Question 6

What are soluble substances?

Answer 6

• Substances that can dissolve in a liquid

Question 7

What are Esters?

Answer 7

• A family of compounds often used as perfumes

- Made by reacting an alcohol with an organic acid to produce an ester + water

Question 8

How do Emulsifiers work?

Answer 8

• They mix oil and water
• They have two ends:
  > hydrophilic end attracts to water
  > hydrophobic end attracts to oil
  > the attraction holds oil and water together

Question 9

What does it mean if a substance is volatile?

Answer 9

• It evaporates easily

Question 10

Name the four types of food additives?

Answer 10

• Antioxidants
• Food colours
• Flavour enhancers
• Emulsifiers

Question 11

What is used to test for carbon dioxide?

Answer 11

• Lime water

Question 12

What happens when sodium hydrogen carbonate (baking powder) is heated?

Answer 12

• It decomposes to make ‘sodium carbonate’ and ‘water’. ‘Carbon dioxide’ gas is also made

Question 13

During cooking, what happens to plants cell walls?

Answer 13

-The heat breaks down the cell wall and the cells become soft

Question 14

What happens during a chemical change?

Answer 14

• New substances are formed
• There is an energy change
• It can’t be easily reversed

Question 15

What happens to proteins when they are cooked/ heated?

Answer 15

• When they are heated, the protein molecules change shape (denature)
• It causes the texture and appearance of the food to change

Question 16

What are the 3 ways to dispose of polymers?

Answer 16

• Landfill sites
• Burning polymers
• Recycling polymers

Question 17

What are the characteristics of plastics with strong forces between polymer molecules?

Answer 17

• High melting points

- Rigid and can’t be stretched

Question 18

How are hydrocarbons made?

Answer 18

• Hydrogen atoms react with carbon atoms to form covalent bonds
• when this happens, carbon atoms share a pair of electrons with hydrogen atoms to make a covalent bond

Question 19

What is an Alkane?

Answer 19

• A hydrocarbon chain with only single covalent bonds
• ‘Saturated’ hydrocarbons
• The main chain will only contain single carbon-carbon bonds (c-c)

Question 20

What are Characteristics of plastics with weak forces between polymer molecules?

Answer 20

• Low melting points

- Can be stretched easily because the polymer molecules can slide over each other

Question 21

What is a polymer?

Answer 21

• A very long chain molecule with repeating units

Question 22

What is polymerisation?

Answer 22

• The process of Alkenes joining together to make a polymer

- this process needs high pressure and a catalyst

Question 23

What is a Monomer?

Answer 23

• A small unsaturated molecule that can be used to make a polymer

Question 24

What is used to test for Alkenes or Alkanes ?

Answer 24

- Bromine water

Question 25

What are Alkenes?

Answer 25

- Hydrocarbon chains with one or more double carbon-carbon (c=c) covalent bonds - Have two shared pairs of electrons - Names of Alkenes always end in -ene

Question 26

How do catalytic converters work?

Answer 26

- They contain catalysts which help polluting chemicals in exhaust gases to react with oxygen

Question 27

What do Catalytic converters do?

Answer 27

- Change carbon monoxide to carbon dioxide

Question 28

Name three things humans do that affects the balance of carbon dioxide in the atmosphere?

Answer 28

1- burning fossil fuels increases carbon dioxide 2- Deforestation means less carbon dioxide is removed 3- increase in world population

Question 29

How are Nitrogen Monoxide and Nitrogen Dioxide made in a car engine?

Answer 29

- Nitrogen and Oxygen from the air react in the hot car engine

Question 30

What are Oxides of Nitrogen?

Answer 30

- Formed in car engines | - cause photochemical smog and acid rain

Question 31

What is Carbon Monoxide?

Answer 31

- A poisonous gas formed from incomplete combustion in a car engine

Question 32

How is Sulfur Dioxide made?

Answer 32

- When fossil fuels that contain sulfur impurities are burned - Causes acid rain

Question 33

What are gas levels in the atmosphere maintained by?

Answer 33

- Respiration - Combustion - Photosynthesis

Question 34

What is Incomplete Combustion?

Answer 34

- When fuel burns without enough oxygen. - Some heat energy is released. - Incomplete combustion of a hydrocarbon produces carbon monoxide - When very little oxygen is provided, carbon and water are produced

Question 35

What is the equation for Incomplete combustion?

Answer 35

Methane + Oxygen = carbon monoxide + water 2CH4 + 3O2 = 2CO + 4H2O

Question 36

What is Combustion?

Answer 36

- When fuels react with oxygen and burn which releases useful heat energy. Needs lots of oxygen - Many fuels are hydrocarbons - Complete combustion of a hydrocarbon produces carbon dioxide and water

Question 37

What is the equation for Combustion?

Answer 37

Methane + Oxygen = carbon dioxide + water CH4 + 2O2 = CO2 + 2H2O

Question 38

What are forces between molecules?

Answer 38

- In hydrocarbon molecules there are: > strong covalent bonds between atoms > weak intermolecular forces > Intermolecular forces between longer hydrocarbons are stronger than forces between shorter hydrocarbons

Question 39

What is cracking?

Answer 39

- Large Alkane molecules can be broken down into smaller, more useful, Alkane and Alkene molecules. - This process is called Cracking - requires a catalyst, high temperature and high pressure - used to make petrol from naphtha

Question 40

What is Fractional Distillation?

Answer 40

- Because different hydrocarbons have different boiling points, crude oil can be separated into useful parts. This is fractional Distillation - Heated in a fractionating column

Question 41

What is crude oil?

Answer 41

- Found in the Earths crust, pumped to the surface - spills into the sea = slick on the surface - can be harmful to wildlife - Used as a fuel, but is being used quicker than it is being produced - Mixture of many hydrocarbons

Question 42

What are polymers made of?

Answer 42

- Tangled very long chain molecules | - The atoms are held together by strong covalent bonds