National Chemistry

2001 General answers

 

1.  (a)  C  (1 mark)

(b)  A and B (1 mark)

(c)  E (1 mark)

 

2.  (a)  D (1 mark)

(b) A (1 mark)

(c) B (1 mark)

 

3.  (a) A and C (1 mark)

(b) A and F (1 mark)

(c) B (1 mark)

 

4.  (a)  C  (1 mark )

(b) E (1 mark)

(c) D and F (1 mark)

 

5. (a) B (1 mark)

(b) A (1 mark )

 

6. (a) B  (1 mark )

(b) A (1 mark)

(c) C (1 mark)

(d) E and F (1 mark)

 

7.  B and C (1 mark each)

 

part 2

 

8. (a) 7 electrons on outer circle; 2 electrons on next circle

None on small circle representing the nucleus

(b) Equal/same number of protons and electrons;

 Equal/same number of positive charges and negative charges

 

9. (a) (i)  1 to 6 and  8 to 14

(ii) insoluble

(b)  Na + O2 ------> Na2O

 

10. (a)

<IMG SRC="polyethene.gif"><BR>

do not miss out any bonds or atoms

 

(b)  (b)thermoplastic

(c) label both axes - actually given here as "%" and "use"

put on the scale  along the way two large boxes  for each use

up the way each large box worth 5;

make sure over half the graph paper is used;

plot points

make sure it is a bar graph.

<each error loses a half mark

 

 

11. (a) to speed up the reaction;

to allow the reaction to take place at lower temperature

(b) As the temperature increases then the % SO2 converted  decreases

Notice it is not the %SO2that decreases - the word converted is important

Notice that  you cannot say that the less SO2 converted then the higher the   temperature - it is the temperature that affects the SO2

 

(c) Pollutant poisonous

(d)

 

12.  (a) Electrolysis

(b) Copper ion is positive

(c)bubbles; a gas; chlorine gas

(d) Conducts electricity

 

13.  (a) oxygen

(b) Same level  (as same amount of air used up)

 

(c) Fe2+ ;  Fe3+ ; Fe2+     P      O2- ; (Fe3+)2(O2-)3

(compound must show the appropriate ion)

 

14.  (a) (i)  Ostwald

(ii) water

(b) Fertilisers; explosives

 

15. (a) (i) A chemical reaction

(ii) portable; easy to carry.

(b) (i) iron to copper (left to right)

            Draw the arrow on or above the wire NOT on the potato.

 

(ii)  increase  the voltage.

(the bigger the gap  the higher  the voltage produced )

 

16. (a) 40 cm3

(b) Same final volume

(c) Steeper curve; more gas given off in same time.

(d) 0.2 g       (catalyst unaffected)

 

17. (a)  (fractional) distillation ?

(b) petrol

(c) Place a volume of petrol in the burette and

time how long it takes to empty into beaker

repeat with lubricating oil

shortest time to empty is the less viscous

 

18. (a)(i) two atoms combined

(ii) covalent

(b) (As the Atomic number increases then the boiling point) increases

(ii) 250-384 oC

2001 General

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