Targeted

Question 1

What is an isotope?

Answer 1

Atoms of an element with the same number of protons but a different number of neutrons

Question 2

What is the formula for Copper Nitrate?

Answer 2

Cu(NO₃)₂

Question 3

What is the formula for Calcium Nitrate?

Answer 3

Cu(NO₃)₂

Question 4

Why is graphite a good lubricant?

Answer 4

• it is arranged in layers, which are able to slide off of one another
• due to the weak forces of attraction between them

Question 5

How do you test for carbon dioxide?

Answer 5

bubble the gas through limewater (1)
if it turns cloudy, carbon dioxide is present (!)

Question 6

How would someone know if a chemical reaction has finished?

Answer 6

• no further changes in colour or odor
• excess reactant

Question 7

How can we make the Rf value in chromatography more accurate?

Answer 7

Longer chromatography paper

Question 8

What are the names of all the apparatus needed for filtration?

Answer 8

• conical flask
• funnel
• filter paper
• residue in funnel
• filtrate at the bottom of the conical flask

(NOT a BEAKER!)

Question 9

How can a sample of pure dry sodium chloride or copper sulfate crystals be obtained from filtrate?

(3 marks)

Answer 9

• heat gently to evaporate half of the water (1 mark)
• cool to room temperature and allow it to evaporate further (1 mark)
• dab the crystals dry (1 mark)

Question 10

Using an oxidation setup with a crucible, how can we find the mass of oxygen that reacts with magnesium/iron?

Answer 10

• find the mass of the crucible, lid and iron/magnesium
• heat to a constant mass
• subtract the final mass by the initial mass to find the mass of oxygen reacted

Question 11

What do bases produce when reacted with water?

Answer 11

A hydroxide

Question 12

Why is potassium higher in the reactivity series than calcium?

Answer 12

Because it’s easier for it to loose its outer electron.

Question 13

What does it mean for an acid to be described as strong?

(2 marks)

Answer 13

• It fully dissociates in water (1 mark)
• to form hydrogen ions (1 mark)

Question 14

Other than universal indicator, what can be used to test the pH of a solution?

Answer 14

A pH meter / probe

Question 15

How does the pH of an originally acidic solution change as an alkaline solution is added?

(4 marks)

Answer 15

• the base neutralises the acid (1 mark)
• so the pH increaces (1 mark)
• untill it reaches pH 7 (1 mark)
• now there is an excess of hydroxide ions (1 mark)

Question 16

Formula for relative atomic mass

Answer 16

(% mass of isotope a x mass of isotope a) + (% mass of isotope b x mass of isotope b) / 100