Chemical Changes

Question 1

How do you know if something is an acid?

Answer 1

It has an H at the front.

Question 2

How do you know if something is an alkali?

Answer 2

It has an OH on the end.

Question 3

What elements go round in pairs and what’s their name?

Answer 3

Non-metals but not group 0.
Diatomic molecules.

Question 4

List the reactivity series decreasing the reactivity as you go down.

Answer 4

Potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold
Platinum

Question 5

What is a displacement reaction?

Answer 5

When a more reactive metal can displace/ replace a lower reactivity metal from its compound and take it’s place.

Question 6

What is Electrolysis?

Answer 6

Using electricity to split compounds into their elements.

Question 7

What is oxidisation?

Answer 7

Loss of electrons.

Question 8

What is reduction?

Answer 8

Gain of electrons.

Question 9

What does the mnemic OILRIG stand for?

Answer 9

Oxidation
is
loss
Reduction
is
gain

Question 10

What is an ionic equation?

Answer 10

Remove spectator ions. Only show the chemicals being reduced or oxidised.

Question 11

What is a half equation?

Answer 11

Reduction and oxidisation of each chemical. Ionic equation split into two.

Question 12

What are weak acids?

Answer 12

Acids which partially ionise in water, releasing some H+ ions.

Question 13

What are strong acids?

Answer 13

Acids which fully ionise in water releasing all of their H+ ions into solution.

Question 14

What are bases?

Answer 14

Substances that have a Ph more than 7. When dissolved in water they are called alkalines.

Question 15

What is a neutralisation reaction?

Answer 15

The reaction of an acid and base to produce water and salt.

Question 16

What is a salt?

Answer 16

Ionic chemicals formed when the hydrogen ion in an acid is replaced by a metal ion.

Question 17

What do acids release?

Answer 17

H+ ions

Question 18

What do alkalines release?

Answer 18

OH- ions

Question 19

How do you make a soluble salt from a base and an acid?
Practical.

Answer 19

1. Add insoluble copper oxide to sulfuric acid and stir. Warm gently on a bunsen burner.
2. The solution turns blue as the reaction occurs, showing that copper sulfate is being formed.
3. When the reaction is complete filter the solution to removed excess copper oxide.
4. We can evaporate the water so that crystals of copper sulfate are left.

Question 20

What indicator do you use for titration?

Answer 20

Phenolphthalein

Question 21

What does electrolysis work on?

Answer 21

Ionic compounds because they have charged ions.

Question 22

What does mnemic PANIC stand for?

Answer 22

Positive
Anode
Negative
Is
Cathode

Question 23

What is the anode and what ion attracts to it?

Answer 23

Positive electrode. Anion (negative ion) attracts to it

Question 24

What is the cathode and what ion attracts to it?

Answer 24

Negative electrode. Cation (positive ion) attracts to it.

Question 25

Where is Aluminium found?

Answer 25

The ore bauxite. It is combined with oxygen as Aluminium oxide.

Question 26

Why does bauxite need to dissolved during electrolysis? What is it dissolved in?

Answer 26

It has a melting point of 2,050 so must be dissolved in cryolite because it lowers the melting point to 1000.

Question 27

At the anode if ions are halogens, what is produced?

Answer 27

Halogen is produced.

Question 28

At the anode, if the ions are not halogens, what is produced?

Answer 28

Oxygen is produced.

Question 29

At the cathode if ions (metals) are more reactive than hydrogen, what is produced?

Answer 29

Hydrogen is produced.

Question 30

At the cathode if ions (metals) are less reactive then hydrogen, what is produced?

Answer 30

The metal is produced.

Question 31

What is the formula for oxidation of water molecules for solution electroylsis?

Answer 31

4OH- ---> 2H2O + O2 + 4e-

Question 32

What is the chemical formula for sulphate and the charge?

Answer 32

SO4 2-

Question 33

What is the chemical formula for nitrate and the charge?

Answer 33

NO3 -

Question 34

What is the chemical formula for silver and the charge?

Answer 34

Ag +

Question 35

What is the chemical formula for carbonate and the charge?

Answer 35

CO3 2-

Question 36

What is the chemical formula for sulphide and the charge?

Answer 36

S 2-

Question 37

What is the chemical formula for oxide and the charge?

Answer 37

O 2-

Question 38

What is the chemical formula for nitride and the charge?

Answer 38

N 3-

Question 39

What is salt? in terms of elements.

Answer 39

Sodium chloride