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Worksheets6.0 Chemical Equilibria
Total questions: 76
Worksheet time: 38mins
Name
Class
Date
1.
irreversible reaction ->
a)
cannot occur in both direction
b)
occur in both direction
2.
NaOH (aq) + HCl (aq) ??? NaCl (aq) + H2O (l)
a)
irreversible reaction
b)
reversible reaction
3.
2H2O2 (aq) ??? 2H2O (l) + O2 (g)
a)
irreversible reaction
b)
reversible reaction
4.
Zn (s) + H2SO4 (aq) ??? ZnSO4 (aq) + H2 (g)
a)
irreversible reaction
b)
reversible reaction
5.
C2H5OH (l) + 3O2 (g) ??? 2CO2 (g) + 3H2O (l)
a)
irreversible reaction
b)
reversible reaction
6.
CaCO3 (s) heat ??? CaO (s) + CO2 (g) in open container.
a)
irreversible reaction
b)
reversible reaction
7.
In Contact process
a)
irreversible reaction
b)
reversible reaction
8.
In Ostwald Process
a)
irreversible reaction
b)
reversible reaction
9.
haber process
a)
reversible reaction
b)
irreversible reaction
10.
2NO (g) + O2 (g) -> 2NO2 (g)
3NO2 (g) + H2O (l) → 2HNO3 (aq) + NO (g)
a)
Ostwald Process
b)
Contact process
11.
S (l) + O2 (g) -> SO2 (g)
*
SO3 (g) + H2SO4 (aq) → H2S2O7 (aq)
H2S2O7 (l) + H2O → 2H2SO4 (aq)
a)
Contact process
b)
Ostwald Process
12.
H2 (g) + I2 (g) <=> 2HI (g)
a)
reversible reaction
b)
irreversible reaction
13.
CH3COOH (l) + C2H5OH (l) <=> CH3COOC2H5 (l) + H2O (l)
a)
reversible reaction
b)
irreversible reaction
14.
PCl5 (g) <=> PCl3 (g) + Cl2 (g)
a)
reversible reaction
b)
irreversible reaction
15.
2NO2 (g) <=> N2O4 (g)
a)
reversible reaction
b)
irreversible reaction
16.
2SO2 (g) + O2 (g) <=> 2SO3 (g)
a)
reversible reaction
b)
irreversible reaction
17.
CaCO3 (s) <=> CaO (s) + CO2 (g) in a close container.
a)
reversible reaction
b)
irreversible reaction
18.
Ag (s) + Fe3+ (aq) <=> Ag+ (aq) + Fe2+ (aq)
a)
reversible reaction
b)
irreversible reaction
19.
Ag+ (aq) + Fe2+ (aq) <=> Ag (s) + Fe3+ (aq)
a)
reversible reaction
b)
irreversible reaction
20.
NH2COONH4 (s) <=> CO2 +NH3 (g)
a)
reversible reaction
b)
irreversible reaction
21.
N2 (g) + 3H2 (g) <=> 2NH3 (g) (haber)
a)
reversible reaction
b)
irreversible reaction
22.
2NH3 (g) <=> N2 (g) + 3H2 (g)
a)
reversible reaction
b)
irreversible reaction
23.
NO2 (g) + O2 (g) <=> NO (g) + O3 (g)
a)
reversible reaction
b)
irreversible reaction
24.
CO (g) + H2O (g) <=> CO2 (g) + H2 (g)
a)
reversible reaction
b)
irreversible reaction
25.
2H2S (g) <=> 2S (s) + 2H2 (g)
a)
reversible reaction
b)
irreversible reaction
26.
reversible reaction <=>
a)
can occur in both direction
b)
cannot occur in both direction
27.
forward reaction ->
a)
rxn proceeding from left to the right
b)
rxn proceeding from right to the left
28.
reverse reaction <-
a)
rxn proceeding from right to the left
b)
rxn proceeding from left to the right
29.
equilibrium involving gases must...
a)
be carried out in a closed container to prevent the gases from escaping
b)
be carried out in a closed container to have maximum pressure of reaction
30.
dynamic equilibrium
a)
Rate of forward rxn = rate of reverse rxn (of reversible rxn)
the amount of substances do not change with time as the c0ndition remain constant.
b)
Rate of forward rxn > rate of reverse rxn (of reversible rxn)
the amount of substances decrease with time as the c0ndition remain constant.
31.
forward rate vs reverse rate. Rate of forward rxn = rate of reverse rxn. A+B -> C+D
a)
concentration of C and D (both product) remain unchanged/ constant.
b)
concentration of A and B (both product) remain unchanged/ constant.
32.
forward rate vs reverse rate. A+B -> C+D
a)
Rate of forward rxn decreases with time as [C] decreases.
Rate of reverse rxn increases with time as more and more D is formed.
b)
Rate of forward rxn increases with time as [C] decreases.
Rate of reverse rxn decreases with time as more and more D is formed.
33.
equilibrium law
a)
When reversible reaction has achieved dynamic equilibrium, ratio of molar concentration of the products to the molar concentration of the reactants, both raised TO THEIR RESPECTIVE STOICHIOMETRIC COEFFICIENTS, is a constant at constant temperature.
b)
When reversible reaction has achieved dynamic equilibrium, ratio of molar concentration of the products to the molar concentration of the reactants, both raised to their respective TO THE CONCENTRATION USED, is a constant at constant temperature.
34.
equilibrium constant, Kc
a)
equilibrium constant in terms of concentration
aA + bB <=> cC + dD
Kc, equilibrium constant = ([C]^c[D]^d)÷([A]^a[B]^b)
b)
equilibrium constant in terms of partial pressure
aA (g) + bB (g) <=> cC (g) + dD (g)
Kp, equilibrium constant = ([Pc]^c[PD]^d) ÷ ([PA]^a[PB]^b)
35.
equilibrium constant, Kp
a)
equilibrium constant in terms of partial pressure
aA (g) + bB (g) <=> cC (g) + dD (g)
Kp, equilibrium constant = ([Pc]^c[PD]^d) ÷ ([PA]^a[PB]^b)
b)
equilibrium constant in terms of concentration
aA + bB <=> cC + dD
Kc, equilibrium constant = ([C]^c[D]^d)÷([A]^a[B]^b)
36.
Partial pressure, P
a)
Of gas A in a mixture: PA = XAPT
(XA = mole fraction of A, PT = total pressure)
b)
Of gas A in a mixture: PA = XA÷PT
(XA = mole fraction of A, PT = total pressure)
37.
Mole fraction of A, Xa. Find partial pressure using mole fraction:
a)
Pa = (mole fraction of a in the mixture) x (total pressure of the mixture)
Pa = XaPtotal
b)
Pa = (mole fraction of a in the mixture) ÷ (total pressure of the mixture)
Pa = Xa ÷ Ptotal
38.
Homogeneous system
a)
has everything present in the same phase. The usual examples include reactions where everything is a gas, or everything is present in the same solution.
b)
has things present in more than one phase. The usual examples include reactions involving solids and gases, or solids and liquids.
39.
Heterogeneous system
a)
has things present in more than one phase. The usual examples include reactions involving solids and gases, or solids and liquids.
b)
has everything present in the same phase. The usual examples include reactions where everything is a gas, or everything is present in the same solution.
40.
when Kp = Kc
a)
for gaseous system, no. of moles of gases is same = on both side of equation, delta n = 0
b)
for gaseous system, no. of moles of gases is same = on both side of equation, delta n > 0 (larger than zero)
41.
Relationship between equilibrium constant and rate constant
a)
At equilibrium.
R forward = R reverse
K1 ÷ k-1 = Kc
Rate constant only affected by temperature & presence of a catalyst
b)
At equilibrium.
R forward = R reverse
K1 ÷ k-1 = Kc
Rate constant only affected by temperature
42.
expression of Kc
a)
equilibrium constant in terms of concentration
aA + bB <=> cC + dD
Kc, equilibrium constant = ([C]^c[D]^d)÷([A]^a[B]^b)
b)
equilibrium constant in terms of partial pressure
aA (g) + bB (g) <=> cC (g) + dD (g)
Kp, equilibrium constant = ([Pc]^c[PD]^d) ÷ ([PA]^a[PB]^b)
43.
expression of Kp
a)
equilibrium constant in terms of partial pressure
aA (g) + bB (g) <=> cC (g) + dD (g)
Kp, equilibrium constant = ([Pc]^c[PD]^d) ÷ ([PA]^a[PB]^b)
b)
equilibrium constant in terms of concentration
aA + bB <=> cC + dD
Kc, equilibrium constant = ([C]^c[D]^d)÷([A]^a[B]^b)
44.
value of equilibrium constants depend on...
a)
temperature only
b)
temperature and pressure
45.
use of reaction quotient (Q). Find reaction quotient, Q
Is the system is in equilibrium?
a)
To indicate the direction of net direction, if any.
b)
To indicate the optimum conditions, to get maximum yield at shortest time and low cost operational.
46.
Q = Kc
a)
system in equilibrium
b)
system is not in equilibrium
Too little product.
47.
Q < Kc
a)
system is not in equilibrium
Too little product.
Net forward rxn will occur to produce more product
b)
system is not in equilibrium
Too much product.
Net reverse rxn will occur to produce more reactant
48.
Q > Kc
a)
system is not in equilibrium
Too much product.
Net reverse rxn will occur to produce more reactant
b)
system is not in equilibrium
Too little product.
Net forward rxn will occur to produce more product
49.
nitrogen dioxide dissociates to produce...
a)
oxygen free radiacal
b)
ozone
50.
oxygen free radical react with oxygen to produce...
a)
ozone
b)
stratosphere
51.
NO2 (g) + O2 (g) <=>
a)
NO (g) + O3 (g)
This equilibrium helps to maintain the concentration of the ozone in stratosphere.
b)
NO (g) + O2 (g) + O3 (g)
This equilibrium helps to maintain the concentration of the ozone and oxygen in stratosphere.
52.
Factors affecting equilibrium system and Le Chatelier's Principle
a)
1. [ ]
2. P
3. T
4. Catalyst
b)
1. [ ]
2. P
3. T
53.
Le Chatelier's principle
a)
1. When a system in dynamic equilibrium is disturbed,
2. The position of equilibrium will CHANGE to remove the effect of the disturbance,
3. So that equilibrium is reestablished.
b)
1. When a system in dynamic equilibrium is disturbed,
2. The position of equilibrium will CONSTANT to remove the effect of the disturbance,
3. So that equilibrium is reestablished.
54.
uses of Le Chatelier's Principle
a)
1. To find the optimum conditions,
2. Get maximum yield,
3. At shortest time,
4. Low cost operational.
b)
1. To find the minimum conditions,
2. Get minimum yield,
3. At longer time,
4. high cost operational.
55.
equation of relationship between equilibrium constant and temperature
a)
Kc = Ae^(-∆H/RT)
b)
Kp = Kc (RT)^(∆n)
56.
linear equation
a)
ln Kc = ln A - (∆H/RT)
b)
ln Kc = ln A + (∆H/RT)
57.
graph ln Kc vs (1/T) with gradient -(∆H/R)
a)
for endothermic rxn
b)
for exothermic rxn
58.
plot graph to determine ∆H rxn
a)
graph ln Kp vs 1/T
b)
graph ln Kp vs T
59.
Important of industrial processes
a)
Yield is high
Rate reaction fast
Cost production is low
Avoid using very high temperature & pressure
b)
Yield is low
Rate reaction slow
Cost production is high
Using very high temperature & pressure
60.
To manufacture ammonia
N2 (g) + 3H2 (g) <=> 2NH3 (g)
∆H = -92kJ mol-¹
a)
Uses: manufacture fertiliser, explosive, detergent, polymers & nitric acid.
b)
Uses manufacture:
1. nitrate fertilisers.
2. Organic nitrogen compounds (dynamite & TNT, trinitrotoluene, organic dyes).
61.
Temperature too low:
a)
a. Low rate,
b. Low yield.
b)
a. constant rate,
b. High yield.
62.
To manufacture ammonia
a)
1. favours high pressure (higher cost of pipe & container must strong enough to withstand 200-1000 atm).
2. Its exothermic: favours low temperature but rate rxn low, longer time for the system to achieve equilibrium. Normal use temperature: 450°C ~ 550°C
Catalyst: Iron
b)
Favour forward rxn:
1. 1atm -> 95%
2. Exothermic, favour low temperature but low rate rxn (should be normally use 450°C - 550°C)
Catalyst: Vanadium pentoxide.
63.
To produce H2SO4, sulphuric acid.
a)
Favour forward rxn:
1. 1atm -> 95%
2. Exothermic, favour low temperature but low rate rxn (should be normally use 450°C - 550°C)
Catalyst: Vanadium pentoxide.
b)
1. favours high pressure (higher cost of pipe & container must strong enough to withstand 200-1000 atm).
2. Its exothermic: favours low temperature but rate rxn low, longer time for the system to achieve equilibrium. Normal use temperature: 450°C ~ 550°C
Catalyst: Iron
64.
To produce nitric acid.
a)
Uses manufacture:
1. nitrate fertilisers.
2. Organic nitrogen compounds (dynamite & TNT, trinitrotoluene, organic dyes).
b)
Uses: manufacture fertiliser, explosive, detergent, polymers & nitric acid.
65.
To produce nitric acid, HNO3 .
a)
Temperature: 900°C
Pressure: 4~10 atm
Then cool to room temperature
b)
Temperature: 450°C ~ 550°C
Pressure: 200-1000 atm
Catalyst: Iron
66.
To manufacture ammonia
a)
Uses: manufacture fertiliser, explosive, detergent, polymers & nitric acid.
b)
Uses manufacture:
1. nitrate fertilisers.
2. Organic nitrogen compounds (dynamite & TNT, trinitrotoluene, organic dyes).
67.
To manufacture ammonia
a)
Azeotrope:
68% HNO3
32% H2O
b)
Azeotrope:
78% HNO3
22% H2O
68.
haber process
a)
To manufacture ammonia
N2 (g) + 3H2 (g) <=> 2NH3 (g) (haber)
∆H = -92kJ mol-¹
Uses: manufacture fertiliser, explosive, detergent, polymers & nitric acid.
Le Chatelier's Principle:
Normal use temperature: 450°C ~ 550°C
Catalyst: Iron
b)
To produce nitric acid.
Azeotrope:
68% HNO3
32% H2O
69.
contact process
a)
To produce H2SO4, sulphuric acid.
Favour forward rxn:
1. 1atm -> 95%
2. Exothermic, favour low temperature but low rate rxn (should be normally use 450°C - 550°C)
Catalyst: Vanadium pentoxide.
b)
To produce nitric acid.
Azeotrope:
68% HNO3
32% H2O
70.
ostwald process
a)
To produce nitric acid.
Azeotrope:
68% HNO3
32% H2O
b)
To produce H2SO4, sulphuric acid.
Favour forward rxn:
1. 1atm -> 95%
2. Exothermic, favour low temperature but low rate rxn (should be normally use 450°C - 550°C)
Catalyst: Vanadium pentoxide.
71.
general reversible rxn
a)
aA + bB <=> cC +dD
b)
aA + bB → cC +dD
72.
Kc is...
a)
equilibrium constant in terms of concentration
b)
equilibrium constant in terms of partial pressure
73.
Kp is...
a)
equilibrium constant in terms of partial pressure
b)
equilibrium constant in terms of concentration
74.
relationship Kc vs Kp
a)
Kp = Kc (RT)^(∆n)
b)
Kc = Ae ^ (-∆H/RT)
75.
relationship Kc vs rate constant
a)
k¹÷k-¹ = Kc
b)
Kc = Ae ^ (-∆H/RT)
76.
relationship equilibrium constant vs temperature
a)
Kc = Ae ^ (-∆H/RT)
b)
Kp = Kc (RT)^(∆n)
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