Page 282 - Chemistry

= 3 = 122.95
0.0244
= 123(no units) penalize for units

(f) 123-90 = 33 ½
16 + (2x1) = 18x = 33
33
x = / 18 = 1.833
x = 2 ½

2. (a) (i)
Observation Inference
- Solid dissolves, yellowish solution. - Soluble compound.
- Colourless fumes/vapour are - Mix with water is exothermal heat is
produced. produced. (1 mk)
- boiling tube becomes warm.(1 mk)
(ii)
Observation Inference
- Blue litmus turns red. - Presence of H /H 3O in the solution.
+
- No effect on litmus paper. - Solution is acid (1 mk)

(iii) Observation Inference 2+, 3+
2+,
- White ppt. soluble in excess. - Pb Zn Pb present. (1 mk)
(1 mk)

(iv)
Observation Inference
3+ 2+
- White ppt. persisted - Al or Pb probably present
insoluble in excess
(v)
Observation Inference
- Mixture remains colourless/ No yellow - Pb absent (1glim).
2+
ppt. seen. (1 mk) - Al present
3+

(vi)
Observation Inference
- White ppt. seen. (1 mk) - SO 4 , CO 3 SO 3 absent
2-
2-,
2-
- Cl- is present (probably present)

(B(b)
Observation Inference
- Solid melts forming a colourless and ignites - Low compound organic compound/presence
/burns with of
Smoky / sooty flame. (1 mk) or –C C
C = C
(accept absence of saturated organic
compound). (1 mk)

Observation Inference
(c) (i) - Dissolves in water forming colourless - Solution compound /polar compound

solution
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