exam

Question 1

which ion makes the solution acidic?

Answer 1

hydrogen ion

Question 2

what type of reaction is this?

Answer 2

neutralisation

Question 3

explain what happens to sodium atoms and to oxygen atoms when sodium reacts with oxygen to produce sodium oxide

Answer 3

1) sodium atoms lose one electron
2) oxygen atom gain 2 eletrons
3)two sodium atoms form an ionic bond with one oxygen atom
4) forming NA+ and O2- ion

Question 4

give two observations seen during the reaction

Answer 4

white smoke is seen
yellow flames appear

Question 5

descrive two differences in the observations if potassium is used instead of sodium

Answer 5

lilac flames are seen
potassium burns faster

Question 6

what is the correct order of founding of protons electrons and neutrons

Answer 6

electron-proton-neutron

Question 7

why does solid sodium chloride not conduct electricty

Answer 7

because ions are not free to move

Question 8

suggest an element that could be used to make the inert electrons

Answer 8

carbon/grphite

Question 9

describe how solid magnesium chloride is obtained from the reaction mixture

Answer 9

1)crystallisation
2) filter to remove excess magnesium

Question 10

the reaction between magnesium and hydrochloric acid is a redox reaction.

Answer 10

1)oxidation has occured to magnesium atoms
2)magnesium atoms have lost 2 electrons

Question 11

which pair of substances both contain hexagonal rings?

Answer 11

fulllerenes and graphene

Question 12

explain why the structure of copper allows the conduction of thermal energy

Answer 12

1)delocated electrons
2) can move through the whole structure
3) and transfer energy

Question 13

explain why copper oxide has a high melting point

Answer 13

a lot of energy is required to break the strong electrostatic force of attraction which are between the oppositely charged ions

Question 14

explain why water has a low melting point

Answer 14

a little amount of energy is required to break
the weak inter molecular forces