T4 - Inorganic chemistry

Question 1

What is the positive flame test for lithium?

Answer 1

Crimson red

Question 2

What is the positive flame test for sodium?

Answer 2

Yellow - orange

Question 3

What is the positive flame test for potassium?

Answer 3

Lilac

Question 4

What is the positive flame test for rubidium?

Answer 4

Red/purple

Question 5

What is the positive flame test for caesium?

Answer 5

Blue/violet

Question 6

What is the positive flame test for beryllium?

Answer 6

N/A

Question 7

What is the positive flame test for magnesium?

Answer 7

N/A

Question 8

What is the positive flame test for calcium?

Answer 8

Brick red

Question 9

What is the positive flame test for strontium?

Answer 9

Crimson red

Question 10

What is the positive flame test for barium?

Answer 10

Apple green

Question 11

Define thermal decomposition

Answer 11

The breaking down of a substance using heat energy

Question 12

What is produced when carbonates decompose? (Give equation)

Answer 12

Metal oxide and carbon dioxide
G1 - M2CO3 —> M2O + CO2
G2 - MCO3 —> MO + CO2

Question 13

What is an acid?

Answer 13

Hydrogen ion donor

Question 14

What is a base?

Answer 14

Hydrogen ion accepting

Question 15

What is an alkali?

Answer 15

A base that dissolves in water

Question 16

What is the trend in solubility down group 2 hydroxides?

Answer 16

The solubility increases down the group

Question 17

What is the trend in solubility down group 2 sulfates?

Answer 17

The solubility decreases down a group

Question 18

Trends in ionisation energy down group 2 and explain why.

Answer 18

Ionisation energy decreases down the group

Size - Atomic radius increases so the electron is further away from the nucleus so is less attracted by the positive nucleus
Nuclear charge - Number of protons increase so there’s a greater attraction to outer electrons (This factor is outweighed)
Shielding - There is an extra shell of electrons for each element downwards, which increases shielding, decreasing the attraction to the outer electron

Question 19

What is the colour of pure elemental chlorine?

Answer 19

Green gas

Question 20

What is the colour of chlorine dissolved in water?

Answer 20

Pale green

Question 21

What is the colour of chlorine dissolved in cyclohexane?

Answer 21

Pale green

Question 22

What is the colour of pure elemental bromine?

Answer 22

Red-brown liquid

Question 23

What is the colour of bromine dissolved in water?

Answer 23

Orange

Question 24

What is the colour of bromine dissolved in cyclohexane?

Answer 24

Darker orange

Question 25

What is the colour of pure elemental iodine?

Answer 25

Grey/silver solid or a purple gas

Question 26

What is the colour of iodine dissolved in water?

Answer 26

BrownW

Question 27

What is the colour of iodine dissolved in cyclohexane?

Answer 27

Purple

Question 28

Which halogen and group 1 metal will give the most vigorous reaction?

Answer 28

F and Fr

Question 29

When a halogen and metal react, which is the oxidising agent and which is the reducing agent?

Answer 29

Halogen is the oxidising agent Metal is the reducing agent

Question 30

What is the trend in electronegativity in group 7 and explain why?

Answer 30

Decreases down a group - S: Has a larger atomic radius, so electrons are further away - N: More protons, larger nuclear charge = more attraction - S: Greater sheilding = less attraction

Question 31

What is the method for halogen displacement practical?

Answer 31

1. Add halide to halogen in solution 2. Add organic solvent (cyclohexane) 3. Gently shake and allow to settle 4. Observe layers and colour changes

Question 32

In the halogen displacement practical, why does the cyclohexane layer sit on top?

Answer 32

The water layer is more dense than the cyclohexane

Question 33

Why is an organic solvent added in the halogen displacement practical?

Answer 33

As the displaced halogen and organic solvent are both non-polar, so they interact better and have better london forces between them.