CHEMISTRY PAST PAPERS
QUESTIONS AND ANSWERS
2023
1. Why is helium used in balloons rather than hydrogen? inert explosive
Helium is i___________ and not ex_________
2. Why does sulphur dioxide effect calcium carbonate water acid rain cor-
(marble) buildings? rodes
Sulfur dioxide reacts with w_______ to form a_____
r_____
This c__________ limestone
3. What is the chemical equation and ion for the salts; Cl 1- NO3 1- CO3
chloride ______ ___2- SO4 2nitrate ______ ___ carbonate ______ ___
sulfate ______ ___
4. What is created if barium carbonate is eaten? hydrochloric acid
Reacts with h_________ a_________ in stomach to barium chloride
make b_________ c_________ + W______ + C___ water CO2
5. If someone eats barium hydroxide solution by mistake barium sulphate
and it is poisonous, why would the person be given magnesium
sulphate as a treatment?
Turns the BH into b_________ s_________ which isn't
poisonous
{MM - they may ask any silly question just to see if
you can do the Chem - you're not supposed to know
what is poison}
6. What are oxidation and reduction reactions? electrons oxygen
Either (i) gaining or losing e_________ (This is a redox
reaction)
Or (ii) gaining or losing o_________
, CHEMISTRY PAST PAPERS
QUESTIONS AND ANSWERS
2023
7. What is a half equation? balanced elec-
A b_________ equation showing the gaining or losing trons
of e_________
8. What type of reaction are these oxidised reduced
oxidised neu-
Carbon + oxygen carbon o____________ tralised
iron (iii) oxide + carbon iron r____________
carbon o____________
Calcium hydroxide + nitrogen oxide n_____________
9. Why is Calcium hydroxide + nitrogen oxide a neutral- metal base non
isation reaction? metal acid
Calcium is a m__________ so calcium oxide is a
b__________. Nitrogen is a n____ m_______ so nitrogen
dioxide is a_________
10. Why is universal indicator not a good choice of indi- gradual sharp
cator for titration? What better? methyl
Colour change is g____________ and end point not s____________
M____________ orange, or pheonophalin
11. If you have a super reactive element, where should oil you store it to
keep it safe? a. under o____
12. What are electrodes made of when doing electrolysis? graphite
G______________
13. If electrolysising pure aluminium oxide why do you high melting point
need a high temperature? What do you do instead? dissolve cryolite
QUESTIONS AND ANSWERS
2023
1. Why is helium used in balloons rather than hydrogen? inert explosive
Helium is i___________ and not ex_________
2. Why does sulphur dioxide effect calcium carbonate water acid rain cor-
(marble) buildings? rodes
Sulfur dioxide reacts with w_______ to form a_____
r_____
This c__________ limestone
3. What is the chemical equation and ion for the salts; Cl 1- NO3 1- CO3
chloride ______ ___2- SO4 2nitrate ______ ___ carbonate ______ ___
sulfate ______ ___
4. What is created if barium carbonate is eaten? hydrochloric acid
Reacts with h_________ a_________ in stomach to barium chloride
make b_________ c_________ + W______ + C___ water CO2
5. If someone eats barium hydroxide solution by mistake barium sulphate
and it is poisonous, why would the person be given magnesium
sulphate as a treatment?
Turns the BH into b_________ s_________ which isn't
poisonous
{MM - they may ask any silly question just to see if
you can do the Chem - you're not supposed to know
what is poison}
6. What are oxidation and reduction reactions? electrons oxygen
Either (i) gaining or losing e_________ (This is a redox
reaction)
Or (ii) gaining or losing o_________
, CHEMISTRY PAST PAPERS
QUESTIONS AND ANSWERS
2023
7. What is a half equation? balanced elec-
A b_________ equation showing the gaining or losing trons
of e_________
8. What type of reaction are these oxidised reduced
oxidised neu-
Carbon + oxygen carbon o____________ tralised
iron (iii) oxide + carbon iron r____________
carbon o____________
Calcium hydroxide + nitrogen oxide n_____________
9. Why is Calcium hydroxide + nitrogen oxide a neutral- metal base non
isation reaction? metal acid
Calcium is a m__________ so calcium oxide is a
b__________. Nitrogen is a n____ m_______ so nitrogen
dioxide is a_________
10. Why is universal indicator not a good choice of indi- gradual sharp
cator for titration? What better? methyl
Colour change is g____________ and end point not s____________
M____________ orange, or pheonophalin
11. If you have a super reactive element, where should oil you store it to
keep it safe? a. under o____
12. What are electrodes made of when doing electrolysis? graphite
G______________
13. If electrolysising pure aluminium oxide why do you high melting point
need a high temperature? What do you do instead? dissolve cryolite
