C2.5 Synthesis

Question 1

polymer

Answer 1

Large molecule made by linking together many small molecules (monomers).

Question 2

thermosetting

Answer 2

A polymer that cannot be melted or remoulded again once formed.

Question 3

fraction

Answer 3

A constituent part of crude oil produced by fractional distillation.

Question 4

addition

Answer 4

In polymer chemistry, a large molecule formed from alkene monomers added together to form chains.

Question 5

alkene

Answer 5

A hydrocarbon in which two or more carbon atoms are joined by double bonds.

Question 6

displayed formula

Answer 6

A diagram of the structure of a molecule in which the elements are represented by letters and the bonds are shown by straight lines.

Question 7

atom economy

Answer 7

The proportion of reactants that are converted into useful products.

Question 8

hydrocarbon

Answer 8

An organic compound containing just hydrogen and carbon.

Question 9

toxic

Answer 9

Poisonous. Toxic substances may cause death if they are swallowed, breathed in or come into contact with the skin.

Question 10

saturated hydrocarbon

Answer 10

A compound of hydrogen and carbon in which there are only single bonds. Alkanes are saturated hydrocarbons.

Question 11

percentage yield

Answer 11

The percentage of a theoretical yield that you actually get in a reaction.

Question 12

sustainable development

Answer 12

Meeting the needs of the existing population without damaging the ability of future generations to meet their own needs.

Question 13

fractional distillation

Answer 13

An industrial process used to separate the constituent parts of crude oil.

Question 14

synthesis

Answer 14

Making a substance using chemical reactions.

Question 15

unsaturated monomer

Answer 15

A small molecule that can form a polymer because it contains a double bond.

Question 16

plasticiser

Answer 16

A substance added to polymers to make them softer and more flexible. Plasticisers allow polymer chains to slide over each other more easily.

Question 17

condensation

Answer 17

A type of reaction in which two molecules join together to make a larger one, with water as a by-product.

Question 18

double bond

Answer 18

Two covalent bonds between two atoms, involving two shared pairs of electrons.

Question 19

formula

Answer 19

An abbreviation for a substance with two or more atoms. The formula contains the symbols for the different elements in the substance, with numbers to show if there are two or more atoms of a particular element present.

Question 20

repeating unit

Answer 20

A section or monomer of a polymer which shows its structure.

Question 21

polymerisation

Answer 21

In chemistry the process by which small alkenes (monomers) join together to form large molecules (polymers).

Question 22

thermoplastic

Answer 22

A polymer that softens or melts when heated and becomes hard again when cooled.

Question 23

toxicity

Answer 23

How toxic or poisonous a substance is. Very toxic substances have a high toxicity.

Question 24

state symbol

Answer 24

Symbol used in chemical equations to show whether a substance is solid (s), liquid (l), gas (g) or dissolved in water (aq).

Question 25

theoretical yield

Answer 25

The maximum calculated amount of product that can be obtained from a particular quantity of reactants. Also called expected yield.

Question 26

empirical

Answer 26

Worked out from an experiment. An empirical formula is worked out dividing the mass of each element in a compound by its relative atomic mass.

Question 27

expected yield

Answer 27

See theoretical yield.

Question 28

hydrogenate

Answer 28

To react with hydrogen.

Question 29

polyunsaturated

Answer 29

A substance (usually a fat) that has more than one double bond.

Question 30

viscous

Answer 30

Sticky or thick. Liquids with high viscosity are difficult to pour.

Question 31

cross-links

Answer 31

Strong covalent bonds that form between polymer molecules.

Question 32

monounsaturated

Answer 32

A substance (usually a fat) that only has one double bond.

Question 33

monomer

Answer 33

A small molecule, for example an alkene, that can be joined to many other small molecules to form a much larger molecule.

Question 34

biodegradable

Answer 34

Able to be broken down by soil bacteria.

Question 35

covalent bond

Answer 35

A type of chemical bond in which a pair of electrons is shared between two atoms.

Question 36

alkane

Answer 36

A hydrocarbon in which all the bonds between the carbon atoms are single bonds.

Question 37

relative formula mass

Answer 37

The mass of a molecule relative to the mass of a carbon atom. Abbreviated to Mr.

Question 38

relative atomic mass

Answer 38

The mass of an atom compared to the mass of a carbon atom, which has a relative atomic mass of 12. Abbreviated to Ar.

Question 39

molecular formula

Answer 39

A chemical code that shows how many of each atom there are in a molecule.

Question 40

actual yield

Answer 40

The amount of product obtained from a chemical reaction in reality. This may differ from the theoretical or expected yield because the raw materials may not be pure or because the reaction may not be complete.

Question 41

cracking

Answer 41

A type of chemical reaction in which large alkane molecules are decomposed to form smaller alkanes and alkenes.

Question 42

unsaturated hydrocarbon

Answer 42

A compound of hydrogen and carbon in which there is one or more double bond. Alkenes are unsaturated hydrocarbons.

Question 43

raw material

Answer 43

A starting substance for the manufacture of a particular chemical.