Organic chemistry (up to esters) Flashcards Preview

Chemistry GCSE > Organic chemistry (up to esters) > Flashcards

Flashcards in Organic chemistry (up to esters) Deck (48)
Loading flashcards...
1

What is a hydrocarbon?

any compound formed from only hydrogen and carbon atoms

2

What is a homologous series?

a group of organic compounds that react in a similar way

3

What are saturated compounds?

compounds where each carbon atom forms four single covalent bonds

4

What are alkanes?

the smallest type of hydrocarbon with single carbon bonds (C-C)
a homologous series (all react in a similar way)
saturated compounds

5

What is the general formula for an alkane?

CnH2n+2

6

What are the first four alkanes?

methane
ethane
propane
butane

7

How do the properties of hydrocarbons change as the chain gets shorter?

the shorter the chain...
-the more runny and less viscous (gloopy) it is
-the more volatile it is (turns into a gas at a lower temp so has a lower boiling point)
-the more flammable the hydrocarbon is

8

When does complete combustion occur?

when there is a plentiful supply of oxygen

9

What are the waste product of the complete combustion of any hydrocarbon?

carbon dioxide and water vapour

10

(complete combustion of a hydrocarbon)
hydrocarbon + oxygen ->

carbon dioxide + water (+ energy)

11

What is crude oil?

a fossil fuel formed from remains of organisms buried in mud over millions of years, which can be drilled up to be used
it is also a mixture of lots of different hydrocarbons

12

What is fractional distillation used for?

used to separate hydrocarbon fractions in crude oil

13

Explain the process of fractional distillation.

-the oil is heated and the gas enters a fractioning column
-there's a temperature gradient (hotter at the bottom and cooler towards the top)
-longer hydrocarbons have higher boiling points so condense into liquids lower down the column so drain off lower down the column
-shorter hydrocarbons have lower boiling points so condense towards the top of the column

14

What is cracking?

splitting long chain hydrocarbons into smaller hydrocarbons
(because shorter chain hydrocarbons are more useful)

15

What are the two types of cracking?

catalytic cracking (using a catalyst)
steam cracking (using steam)

16

What happens in catalytic cracking?

-long chain hydrocarbons are heated to vaporise them
-the vapour is passed over a hot powdered aluminium oxide catalyst
-the long chain hydrocarbons split apart on the surface of the catalyst

17

What happens in steam cracking?

-long chain hydrocarbons are heated to vaporise them
-the long chain hydrocarbons are mixed with steam
-then they are heated to a very high temperature

18

What are alkenes?

unsaturated hydrocarbons with a double carbon bond (C=C)
they are much more reactive than alkenes

19

What is the general formula for alkenes?

CnH2n

20

What are the first four alkenes?

ethene
propene
butene
pentene

21

(incomplete combustion of alkenes in air)
alkene + oxygen ->

carbon +carbon monoxide + carbon dioxide + water (+ energy)

22

What is a functional group?

a group of atoms in a molecule that determine how the molecule typically reacts
eg. all alkenes have a C=C bond so all act in a similar way

23

What is hydrogenation?

the addition of hydrogen
hydrogen can react with the double bonds of carbon (in an alkene) to open up the double bond and form the equivalent alkane

24

Alkenes react via addition reactions, what does this mean?

the carbon-carbon double bond will open up to leave a single bond and a new atom is added to each carbon

25

How do alkenes react with halogens?

in addition reactions
the molecules formed are saturated, with the C=C carbons each becoming bonded to a halogen atom

26

How can you test for alkenes?

alkenes turn bromine water colourless (whereas if it is added to a saturated compound it would remain bright orange)

27

What happens when steam reacts with alkenes?

water is added across the double bond and an alcohol is formed
eg. ethene and water in the presence of a catalyst produce ethanol, which can be used to make alcohol in industry

28

What are polymers?

long molecules formed when lots of small molecules (monomers) join together

29

What is polymerisation?

the reaction where monomers join together to form polymers

30

What is addition polymerisation?

when lots of unsaturated monomer molecules (alkenes) open up their double bonds and join together to form polymer chains
(the only product is the polymer)