questions you Keep Getting Wrong

Question 1

what colour does the solution change in the experiment of magnesium + copper sulphate

Answer 1

Blue —-) colourless

Question 2

What happens to the copper at the end of the experiment with magnesium and copper sulphate?

Answer 2

Copper coats the magnesium and then sinks to the bottom

Question 3

What is the colour change in the thermal decomposition of calcium carbonate and state the products

Answer 3

Colourless—-) cloudy

Calcium oxide + carbon dioxide

Question 4

What is the colour change in the thermal decomposition of copper carbonate and state the products

Answer 4

Green —-) black

Copper oxide + carbon dioxide

Question 5

What is the state symbol for when iron has rusted

Answer 5

(S)
Hydrated iron (iii) oxide is a solid

Question 6

What is the difference between when iron reacts with hydrochloric acid and when iron reacts with cold water

Answer 6

Slow fixing, test tube becomes slightly warm and turns a green solution

But no reaction with cold water

Question 7

When calcium carbonate reacts with hydrochloric acid what is formed

Answer 7

Calcium carbonate + hydrochloric acid —-) calcium chloride + water + carbon dioxide

Question 8

What are the chemical names for limestone, lime water and quick lime

Answer 8

Calcium carbonate is lime stone
Calcium hydroxide is lime water
Calcium oxide is quick lime

Question 9

What colour is copper oxide

Answer 9

Black

Question 10

What colour is litmus in neutral solutions

Answer 10

Purple

Question 11

During metal extraction, which economic factors are considered?

Answer 11

Price of the reducing agent

Energy of fuel

Question 12

What are two exceptions of covalent compounds that can be used in electrolysis

Answer 12

Ammonia

Hydrogen chloride

Question 13

Give one property of carbon dioxide that makes it appropriate in fire extinguishers

Answer 13

More dense than oxygen

Question 14

What happens when excess carbon dioxide is bubbled through lime water?

Answer 14

Solution turns colourless

(Remember that when normal amount of carbon dioxide is bubbled through limewater solution turns cloudy. This experiment is used to investigate respiration)

Question 15

What is sacrificial protection

Answer 15

Process where more reactive metal prevents a less reactive metal from corroding

Question 16

What is an allow, and why is aluminum alloy stringer than pure aluminum alloy

Answer 16

Alloy is a mixture of more than one elements, and contains a metal

Because alloy has different sized ATOMS which disrupt the regular lattice structure so IONS are not able to slide over each other

Question 17

What is the anode rule and what is the cathode rule

Answer 17

Anode rule asks if the ion is a halide or not, and if it is, the halide will go to the anode and form hydrogen

Cathode rule is whether it is more reactive or less reactive than hydrogen, and less reactive element will go to the cathode

Question 18

For oxidation half equation and for reduction half equation, what side does the electron go on

Answer 18

For oxidation, electron goes on the right side(because it is being lost and in chem u don’t show negative electrons)
For reduction, electron goes on the left side

Question 19

Copper and nitric acid is in a molar ratio 1:4

0.05 mol Cu reacts with 0.4 mol nitric acid. Calculate the limiting reactant

Answer 19

Copper is limiting reactant

Go to ur exercise book to see the full reasoning and answer