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Flashcards in Chemistry 1b Deck (44)
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What is cracking ?

When you split a long-chain hydrocarbon to form more useful hydrocarbons.

1

How are long hydrocarbon chains broken down ?

Thermal decomposition

2

Describe the process of cracking

1. Hydrocarbon chain is heated
2. Passed over aluminum oxide catalyst
3. The molecules CRACK over the catalyst

3

What's are the first two Alkenes ?

Ethene and propene

4

What is a way of testing if an oil is unsaturated ?

Bromine water

5

How does bromine water show if an oil is unsaturated ?

It reacts with the oil by opening the double bonds this decolorises the usual brown bromine water

6

What is ethene reacted with to make ethanol ?

Steam (H2O) - in the presence of a catalyst

7

True or False - ethanol made from ethene is used in alcohol

False

8

How is ethanol in alcohol made ?

Fermentation

9

What is a major use for Alkenes ?

Polymers

10

How are polymers made ?

By joining together lots of the same small alkene molecules to form very large molecules

11

What is the polymer made from...
Ethene
Propene

Polythene
Polypropene

12

How are polymers used ?
Give three examples

Plastic bags / milk cartons / credit cards / memory foam - any form of plastic

13

What is a big problem with polymers ?

They are not biodegradable

14

What Does the word 'biodegradable' mean ?

When something is broken down by bacteria

15

What are the two ways of extracting oil from plants or seeds ?

•Crushing and pressing
•Solvents

16

Explain the process of crushing to extract oil

1. Plant material crushed, then placed between metal plates and squash the oil out
2. It is then separated from the plant material in a centrifuge

17

What do oils provide when consumed ?

Energy

18

Why does cooking with oil speed up the process ?

They have higher boiling points than water, so they can be cooked at higher temperatures and therefore quicker

19

What does 'monosaturisation' mean ?

Fats contain one C=C double bond

20

Explain the process of hydrogenation

Hydrogenation is the process where unsaturated oils are hardened. The oils are reacted with hydrogen bubbles in the presence of a nickel catalyst at 60 degrees

21

What are trans fats and how do they occur ?

Trans fats are believed to be very bad for you, they are caused when you partially hydrogenate an oil

22

What do emulsifiers do ?

They make water and oil mix

23

What part of the emulsifier is hydrophilic (water loving) ?

The head

24

The ............. Is hydrophobic

Tail

25

How do emulsifiers help oil and water mix ?

The hydrophobic tails lath on to oil droplets however the hydrophilic heads stay in water. This keeps the oil in very small droplets which stops the oil forming layers, so it mixes

26

What was wegener's theory ?

Continental drift

27

Explain continental drift

The idea that about 300 million years ago there was just one supercontinent called Pangaea. The continents we know today have DRIFTED apart

28

What evidence did he have of this ?

•Identical fossils of the same crocodile found in both South America and Africa
•Africa and South America se to fit together
•Matching rock types

29

Why was Wegener's theory not accepted ?

•Wegener thought that they had move because of the tides however geologists correctly said this was impossible
•He made some of his numbers up