Inorganic Chemistry

Question 1

What are the alkaline metals?

Answer 1

The elements in group 2.

Question 2

What form do the group 2 metals occur in naturally?

Answer 2

Stable compounds such as calcium carbonate

Question 3

What is the most common reaction group 2 metals undergo?

Answer 3

Redox reactions

Question 4

Why are group 2 elements called a reducing agent?

Answer 4

Because it has been reduced by another species and is itself oxidised.

Question 5

What is the oxidation state of group 2 as an element?

Answer 5

0

Question 6

What is the oxidation state of a group 2 element as a compound?

Answer 6

+2

Question 7

What is the trend in reactivity of group 2 metals?

Answer 7

Increases down the group because of deceasing ionisation energy which means it is easier to lose the outer shell electron.

Question 8

What would you observe in a Magnesium + water reaction?

Answer 8

small amount of effervescence
solid dissolves
cloudy solution

Question 9

As you go down group 2 reactions with water, what would you expect the trend to be?

Answer 9

The reactions get more vigorous as you go down the group.

Question 10

What happens when a group 2 element reacts with hydrochloric acid?

Answer 10

They form hydrogen gas and a colourless solution.

Question 11

What is the trend in ionisation energies as you go down group 2?

Answer 11

decrease

Question 12

Why are group 2 elements better reducing agents as you go down the periodic table?

Answer 12

They are oxidised more easily.

Question 13

What is enthalpy of atomisation or a metal?

Answer 13

The amount of energy required to convert one mole of a solid metal into its gaseous state under standard conditions.

Question 14

Why does atomisation energy decrease down group 2?

Answer 14

Increasing Atomic Radius: As you descend Group 2, the number of electron shells increases so outer shell electron further from nucleus.
Weaker metallic bonds require less energy to overcome.

Question 15

Why is the second ionisation energy larger than the first ionisation energy for the same element?

Answer 15

Nuclear charge has increased after the first electron is removed which makes it harder to remove the second electron
Shielding has decreased leading to stronger attraction between nucleus and other electrons

Question 16

What is magnesium hydroxide used for?

Answer 16

To treat excess stomach acid in antacid tablets
Toothpaste to neutralise mouth acids which cause toot decay

Question 17

What is calcium carbonate used for?

Answer 17

building material
antacid
road making
glass

Question 18

Why are calcium compounds added to acidic soils?

Answer 18

To increase the pH in liming. This is necessary because the uptake of macro and micronutrients is pH dependent.
Optimum pH is around 6/7

Question 19

What is calcium hydroxide used for?

Answer 19

limewater test for CO2
mortar production
soil lining

Question 20

What is Barium sulphate used for?

Answer 20

Barium meal for x-rays of the stomach and digestive system as barium ions are heavy and good at absorbing x-rays.

Question 21

What is chlorine at room temperature?

Answer 21

green gas

Question 22

What is bromine at room temperature?

Answer 22

red-brown liquid

Question 23

What is iodine at room temperature?

Answer 23

grey solid

Question 24

Outline a test for ammonium ions.

Answer 24

1. Add sodium hydroxide to the sample
2. Warm the solution
3. Place damp red litmus paper/indicator near the mouth of the test tube
4. If there were ammonium ions in the test tube, the indicator will turn blue.

Question 25

What order should you test for anions in?

Answer 25

CaSH 1. Carbonate 2. Sulphate 3. Halide

Question 26

Outline the test for carbonate ions.

Answer 26

1. Add dilute nitric acid to the sample 2. If you see bubbles, the compounds could be a carbonate. 3. Test the gas evolved by bubbling through limewater. 4. If there are carbonate ions present in the test tube limewater will turn cloudy.

Question 27

Why does the carbonate test have to come first when testing for anions?

Answer 27

Because if you add Ba 2+ or Ag + ions to substances with carbonate ions, you will see a white precipitate and make the wrong identification.

Question 28

Why does the sulphate test have to come second when testing for anions?

Answer 28

Ag2SO4 is insoluble so if there are any sulphate ions present and you add silver nitrate, you will make the wrong identification.

Question 29

Outline the test for sulphate ions.

Answer 29

1. Add dilute nitric acid to the sample to remove carbonate ions. 2. Add barium chloride 3. If there are any sulphate ions in the test tube, you will see a white precipitate.

Question 30

Why does the halide ion test come last when testing for anions?

Answer 30

False results

Question 31

Outline the test for halide ions.

Answer 31

1. Add dilute nitric acid to the sample to remove carbonate ions. 2. Add silver nitrate 3. If halide ions are present in the sample you will see a precipitate.

Question 32

What colour precipitate is AgCl?

Answer 32

white

Question 33

What colour precipitate is AgBr?

Answer 33

cream

Question 34

What colour precipitate is AgI?

Answer 34

yellow

Question 35

What happens to AgCl in dilute NH3?

Answer 35

dissolves

Question 36

What happens to AgBr in concentrated ammonia?

Answer 36

dissolves

Question 37

What happens to AgI in ammonia?

Answer 37

Nothing - it is insoluble

Question 38

What increases as you go down group 2?

Answer 38

atomic radius speed of reaction with water reactivity solubility of hydroxide

Question 39

What decreases as you go down group 2?

Answer 39

1st ionisation energy melting points solubility of sulphates.

Question 40

What increases as you go down group 7?

Answer 40

atomic radius boiling points reactivity of halogen

Question 41

What decreases as you go down group 7?

Answer 41

Reactivity of halide