Unit 2a

Question 1

Mass number

Answer 1

Total number of protons and neutrons

Question 2

Atomic number

Answer 2

Total number of protons

Question 3

Isotope

Answer 3

Different atomic forms of the same element

Question 4

What do isotopes have?

Answer 4

The same number of protons, but different number of neutrons

Question 5

Ionic compound structure

Answer 5

Giant ionic lattice

Question 6

What are the properties of ionic compounds?

Answer 6

Dissolve easily in water
High melting and boiling points

Question 7

Ionic bonding

Answer 7

Transferring electrons

Question 8

Covalent bonding

Answer 8

Sharing electrons

Question 9

Types of covalent bonding structures

Answer 9

Simple molecular substances
Giant covalent structures (macromolecules)

Question 10

What are the properties of simple molecular substances?

Answer 10

Low melting and boiling points
Don’t conduct electricity

Question 11

An alloy

Answer 11

A mixture of two or more elements, at least one of which is a metal

Question 12

Thermosoftening polymers

Answer 12

Flexible
Melt when heated
Weak intermolecular forces

Question 13

Thermosetting polymers

Answer 13

Not flexible - rigid
Do not melt when heated
Strong intermolecular forces

Question 14

Ar

Answer 14

Relative atomic mass (Mass number)

Question 15

Mr

Answer 15

Relative formula mass

Question 16

Percentage of an element in a compound =

Answer 16

(Ar x No of atoms / Mr of compound) x 100

Question 17

Paper chromatography

Answer 17

A form of separation that allows analysis of food additives

Question 18

Why are alloys harder than pure metals?

Answer 18

The new atoms distort the layers of the metal atoms, making it harder for them to slide over

Question 19

What are the properties of metal?

Answer 19

Giant structure
Delocalised electrons
Conductors of heat and electricity

Question 20

Fullerenes

Answer 20

Molecules of carbon, shaped in hollow balls and arranged in hexagonal tubes

Question 21

Smart materials

Answer 21

Materials that behave differently depending on the conditions

Question 22

An example of a smart material

Answer 22

Nitinol - ‘shape memory alloy’

Question 23

Nitinol

Answer 23

Metal alloy that goes back to it’s ‘remembered shape’ if heated

Question 24

What do nanoparticles contain?

Answer 24

Fullerenes

Question 25

Nanoscience

Answer 25

The use of nanoparticles

Question 26

What can fullerenes be joined together to make?

Answer 26

Nanotubes

Question 27

Nanotubes

Answer 27

Tiny hollow carbon tubes that are very strong

Question 28

What can reduce the percentage yield in a reaction?

Answer 28

You nearly always lose a bit of liquid when filtering
There may be unexpected reactions which use up the reactant

Question 29

Percentage yield =

Answer 29

(Actual yield / Predicted yield) x 100

Question 30

What can gas chromatography be used for?

Answer 30

To identify substances

Question 31

How does gas chromatography work?

Answer 31

A gas carries substances through a column, and substances travel at different speeds so they are separated

Question 32

How are gases identified in gas chromatography?

Answer 32

The recorder detects how long it took for the substances to reach the detector

Question 33

What does the recorder do with gas chromatography results?

Answer 33

Draws a gas chromatograph

Question 34

What are the main examples of giant covalent structures?

Answer 34

Diamond
Graphite
Silicon Dioxide

Question 35

Why do substances with strong covalent bonds have high melting points?

Answer 35

It takes a lot of energy to separate the carbon atoms

Question 36

How do you find the empirical formula?

Answer 36

Write the masses of the elements
Divide by the Ar for each element
Divide the results by the lowest result
Get the ratio in its simplest form

Question 37

What might a food colouring contain?

Answer 37

One dye, or a mixture of dyes

Question 38

What are the advantages of using machines to analyse unknown substances?

Answer 38

Very sensitive
Very fast
Very accurate