Unit 2 - Nature's Chemistry

Question 1

What is crude oil?

Answer 1

It is a mixture of chemical compounds, mainly hydrocarbons

Question 2

What is fractional distillation?

Answer 2

The process used to separate crude oil into fractions according to the boiling points of the components (things that make up) of the fractions

Question 3

What is a fraction?

Answer 3

A group of hydrocarbons with boiling points in a given range

Question 4

Ease of evaporation, boiling point range, viscosity and flammability are related to what of the molecules within the fractions?

Answer 4

The molecular size of the molecules within each fraction

Question 5

Alkanes and alkenes are a subset series of hydrocarbons. How would you identify each?

Answer 5

Alkanes have an “-ane” ending and have no carbon to carbon double bonds,
Alkenes have an “-ene” ending and have a carbon to carbon double bond

Question 6

Are alkanes saturated or not?

Answer 6

They are saturated

Question 7

Are alkenes saturated or not?

Answer 7

Alkenes are not saturated. This is because they have a carbon to carbon double bond

Question 8

How can alkenes be converted to alkanes?

Answer 8

Alkenes can undergo addition reactions that convert them into alkanes

Question 9

What can be used to distinguish an unsaturated alkene from a saturated alkane?

Answer 9

Bromine solution

Question 10

How is ethanol manufactured in industry to meet market demands?

Answer 10

By the catalytic hydration of ethane (an alkene)

Question 11

What is a homologous series?

Answer 11

A homologous series is a set of compounds with the same general formula, similar chemical properties, have similar structural formula and show trends in their physical properties

Question 12

What are isomers?

Answer 12

Isomers are compounds with the same molecular formula but a different structural formula e.g. alkenes and cycloalkanes

Question 13

Chemical formula for cyclohexane?

Answer 13

C6H12

Question 14

What is cracking?

Answer 14

Cracking is an industrial method for producing a mixture of smaller, more useful molecules, some of which are alkenes from crude oil. This is different to fractional distillation of crude oil which produces more long-chained hydrocarbons which aren’t as useful in industrial settings

Question 15

There is a catalyst involved in cracking that allows it to be carried out at a lower temperature. What is the name of the two catalysts that can be used to carry out cracking in the laboratory?

Answer 15

Aluminium oxide or silicate catalyst

Question 16

Carbohydrates are a useful source of energy for the body. An example of a good source of carbohydrates is plants. What elements make up carbohydrates?

Answer 16

Carbon
Hydrogen
Oxygen

Hydrogen and oxygen are in the ratio of 2H:1O

Question 17

What can carbohydrates be sub-divided into category-wise?

Answer 17

Sugars and starches

Question 18

Examples of sugars include glucose, fructose, maltose and sucrose (table sugar). What test can be used to detect most sugars? What sugar is the exception?

Answer 18

Benedict’s test. Sucrose is the exception and can’t be detected by this test

Question 19

How can starch be distinguished from other carbohydrates?

Answer 19

Iodine test

Question 20

What is starch?

Answer 20

Starch is a natural condensation polymer made up of many glucose molecules linked together

Question 21

What do plants convert glucose to for storage?

Answer 21

Starch. (Makes sense since starch is made of many glucose molecules linked together)

Question 22

What happens to starch during digestion?

Answer 22

Starch is hydrolysed into glucose which is carried by the blood stream to the cells of the body

Question 23

What can hydrolyse starch?

Answer 23

Acids and enzymes. E.g. the acid and enzymes found in the stomach

Question 24

What temperature do the enzymes of the body work best at?

Answer 24

Body temperature

Question 25

What happens if the temperature becomes too high for an enzyme?

Answer 25

They are denatured (destroyed)

Question 26

How can ethanol for alcoholic drinks be made?

Answer 26

By fermentation of glucose derived from any fruit or vegetable

Question 27

What catalyses the fermentation of ethanol?

Answer 27

An enzyme in yeast

Question 28

There is a limit to the ethanol concentration of fermentation products. How would the alcohol percentage (concentration) be increased?

Answer 28

By distillation. E.g. for spirits such as whisky

Question 29

Alcohol is a drug which, if taken in excess, can have many harmful effects on the body, especially the liver and brain. The alcoholic content of many drinks is given by units of alcohol.

Answer 29

Doesn’t affect my body cause I’m awesome

Question 30

How are alcohol s identified?

Answer 30

By the -OH group and the ending “-ol” e.g. ethanol

Question 31

How can carboxylic acids be identified?

Answer 31

By the carboxyl ending, the COOH group an the “-oic” name ending

Question 32

What is vinegar a solution of?

Answer 32

Ethanoic acid

Question 33

What can vinegar be used for (other than a great topping for chips)?

Answer 33

It is used in household cleaning products designed to remove lime scale and as a preservative in the food industry

Question 34

What is made when carboxylic acids are reacted with an alcohol?

Answer 34

An ester

Question 35

What type of reaction is this between an alcohol and a carboxylic acid to form an ester?

Answer 35

A condensation reaction

Question 36

What is also made (apart from the ester) is this condensation reaction?

Answer 36

Water. Water is always a by-product of a condensation reaction

Question 37

What are esters useful for?

Answer 37

They are used for food flavouring, industrial solvents, fragrances and materials

Question 38

Give some examples of everyday products that plants are used for.

Answer 38

Soaps, cosmetics, dyes, medicines, foods, food colourings, etc.

Question 39

Medicines are usually made up of many chemicals and only one active ingredient works on the body.

Answer 39

Most tablets only contain a small amount of the active ingredient