C3 questions for brainscape

Question 1

Which dissolved ions make water hard?

Answer 1

magnesium and calcium

Question 2

What is the key difference between permanent and temporary hard water?

Answer 2

Temporary hardness ca be removed by boiling.

Question 3

How is limescale formed?

Answer 3

hydrogen carbonate ions decompose on heating to form solid (precipitate) carbonates

Question 4

Give an advantage of living in a hard water area

Answer 4

Calcium in water is good for growing strong teeth and bones. Also reduces heart disease

Question 5

How does adding sodium carbonate soften water?

Answer 5

The Mg and Ca ions form a precipitate (carbonate) which can be fitered off. The ions are thus removed

Question 6

Why can’t water softened using ion exchange be given to babies?

Answer 6

The Mg and Ca are replaced by sodium ions. Too much sodium is bad for you.

Question 7

Why is chlorine added to our drinking water?

Answer 7

To kill microbes

Question 8

Which group 7 element, other than chlorine, is sometimes added to water?

Answer 8

Fluorine, for healthy teeth.

Question 9

Which two physical processes are involved in distillation?

Answer 9

boiling and condensing

Question 10

Is bond breaking an exo or endothermic process?

Answer 10

Endothermic - you put energy in to break bonds

Question 11

Is bond making an exo or endothermic process?

Answer 11

Exothermic - energy is released when bonds are made

Question 12

Flame test colour - lithium

Answer 12

lithium - crimson

Question 13

Flame test colour - sodium

Answer 13

sodium - yellow

Question 14

Flame test colour - potassium

Answer 14

potassium - lilac

Question 15

Flame test colour - calcium

Answer 15

calcium - red

Question 16

Flame test colour - barium

Answer 16

barium - green

Question 17

Al3+ ions with OH- (hydroxide) ions?

Answer 17

White precipitate of Al(OH)3 which dissolves in excess hydroxide

Question 18

Ca2+ and Mg 2+ ions with OH- (hydroxide) ions?

Answer 18

White precipitates of Mg(OH)2 and Ca(OH)2 form

Question 19

Cu2+ ions with OH- (hydroxide) ions?

Answer 19

blue precipitate forms Cu(OH)2

Question 20

Fe2+ ions with OH- (hydroxide) ions?

Answer 20

green precipitate forms Fe(OH)2

Question 21

Fe3+ ionswith OH- (hydroxide) ions?

Answer 21

rusty brown precipitate forms Fe(OH)3

Question 22

What are the products when a carbonate reacts with acid?

Answer 22

carbon dioxide, water and a salt.

Question 23

What is the chemical test for carbon dioxide?

Answer 23

Bubble it through lime water - it goes milky / cloudy white as a precipitate forms

Question 24

What is the chemical test for sulphate ions?

Answer 24

Add barium chloride solution - a white precipitate forms if a sulhate is present.

Question 25

What is the chemical test for chloride ions?

Answer 25

Add silver nitrate + nitric acid - white precipitate forms

Question 26

What is the chemical test for bromide ions?

Answer 26

Add silver nitrate + nitric acid - cream precipitate forms

Question 27

What is the chemical test for siodide ions?

Answer 27

Add silver nitrate + nitric acid - yellow precipitate forms

Question 28

The alkali metals’ is the name for which group in the periodic table?

Answer 28

Group 1

Question 29

In the periodic table, are elements arranged in order of mass number or atomic number?

Answer 29

Atomic number

Question 30

What 2 products are made when an alkali metal reacts with water?

Answer 30

A hydroxide (alkaline) and hydrogen gas.

Question 31

Which is more reactive - lithium or potassium?

Answer 31

potassium

Question 32

Describe the trend in reactivity in group 1

Answer 32

As you go down the group they get more reactive.

Question 33

What is the charge on each halide ion?

Answer 33

1- (group 7 - they gain 1 electron to get a full shell of 8 or 18)

Question 34

The halogens’ is the name for which group in the periodic table?

Answer 34

Group 7

Question 35

Which is more likely to form a coloured compound - chromium or calcium?

Answer 35

Chromium - because it is a transition metal.