Page 248 - Chemistry

15. (a) – Water level rises. √1 (1 mk)
Grey Iron wool changes to brown. √1 (1 mk) 3 (any one of these scores)
(b) – Oiling and greasing. √1 (1 mk)
- Painting.

16. (a) L is more ionized √1 than K hence reacts faster √1 producing higher
volume of a gas. Or L is a stronger acid therefore ionized faster than K a weaker acid 3
(b) Increasing the temeprature√1 using zinc powder/increasing the concentration of acid.

17. Energy of reaction = Bond breakage + Bond formation. √1
Bond formation = Energy of reaction – Bond Breakage

= -287 – 931 √1 3
= - 1218 K Joules per mole. √1 (3 mks)
18. – No effect on the position of the equilibrium
 1
- RXM is neither endothermic nor exothermic hence not affected by changes in temperature
enthalpy is zero.

19. (a)

 1

21. a)the minimum energy required by the reaction particles to cause a successful collision
to form product
b)i)
Ground compound x 1

½ ½
Un ground compound
Vol. of CO 2 x 1
3
(cm )

NB. I) Sketch curve should be to the left and both flatten not at the same final volume
ii)curve is stop to the left due to the size of particles of ground compound x is
reduced,√ ½ increasing surface area√ ½ of the particles thus increasing area of contact of
22 At equilibrium there will be very little of T that has reacted.√1At equilibrium there will be a lot
of T and very little V produced hence equilibrium lies to the left or forms the reactants√1

www.kcse-online.info 247