1. TV30003 PENGENALAN KIMIA ANALISIS DAN FIZIKAL
SAINS KOHORT 1
12
REVISION EXERCISE 10 (Section C)
Structured and essay questions
10.1
Initial concentration 1.0 mol 0.75 mol -
Change of concentration -2x -x +x
Equilibrium concentration 0.7 mol 0.6 mol 0.15 mol
0.75 – x = 0.6 => x = 0.75 – 0.6 = 0.15
10.2 , where x = 0.2 mol
Initial concentration 1.0 mol 5.0 mol - -
Change of concentration -x -x +x +x
Equilibrium concentration 0.8 mol 4.8 mol 0.2 mol 0.2 mol
10.3
Ag+
Fe2+
Fe3+
Initial concentration -
Change of concentration -0.2 -0.2 +0.2
Equilibrium concentration 0.3 0.3 0.2
2. TV30003 PENGENALAN KIMIA ANALISIS DAN FIZIKAL
SAINS KOHORT 1
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10.4
atm, atm
atm
10.5
Initial concentration 1.0 mol - -
Mole Fraction (MF)
= = =
Equilibrium pressure
a)
b)
3. TV30003 PENGENALAN KIMIA ANALISIS DAN FIZIKAL
SAINS KOHORT 1
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10.6
Initial concentration 2 mol 1 mol -
Change of concentration -2x -x +2x
Equilibrium concentration 0.75 mol 0.375 mol 1.25 mol
2x = 1.25 => x = 0.625
a)
b)
Initial concentration 2 1+x -
Change of concentration -2y -y +2y
Equilibrium concentration 0.25 1.875 + x 1.75 mol
2x = 1.55 => x = 0.875
1+x+y = 1 + 0.875 + x = 1.875 + x
7.41 = 1.875 + x = 6.61
x = 6.61 – 1.875 = 4.735
4. TV30003 PENGENALAN KIMIA ANALISIS DAN FIZIKAL
SAINS KOHORT 1
15
10.7 ,
a) Since this is an exothermic reaction, the value of will decrease if the
temperature increase.
b) No change. (Pressure only increase the yield of product)
c) There are 4 moles of gas on the left and only 3 on the right. By increasing
the volume the pressure is decreased. The system will try to relieve that
pressure by going to the side with more moles of gas. Thus, the reaction
shifts to the left.
d) No changes. (Catalyst only speed up the reaction)
e) When an inert gas (neon) is added to the system in equilibrium at constant
volume, then the total pressure will increase. But when the concentrations of
the products and reactants i.e. ratio of their moles to the volume of the
container will not change. Hence, when an inert gas is added to the system in
equilibrium at constant volume there will be no effect on the equilibrium.
10.8
[
Initial concentration 0.25 -
Change of concentration -x +2x
Equilibrium concentration
0.25 – x
= 0.25 –
= mol
2x =
2(
= mol
5. TV30003 PENGENALAN KIMIA ANALISIS DAN FIZIKAL
SAINS KOHORT 1
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0.25 – x = 2x
2x + x -0.25 = 0
3x = 0.25
X= (substitude x into equation to get the equilibrium concentration)
10.9 ,
a) The forward reaction is exothermic reaction (negative), so the value of
with increase in temperature.
b) No change. (Pressure only increase the yield of product)
c) No changes. (Catalyst only speed up the reaction)
d) When an inert gas is added to the system in equilibrium at constant pressure,
then the total volume will increase. Hence, the number of moles per unit
volume of various reactants and products will decrease. Hence, the
equilibrium will shift towards the direction in which there is increase in
number of moles of gases. Consider the following reaction in equilibrium:
The addition of an inert gas at constant pressure to the above reaction will
shift the equilibrium to the left because the number of moles of reactants is
more than the number of moles of the products.
