Equilibrium Flashcards
1
Q
During a chemical change,there is always ________
A
an energy change
(energy take in or give off in the form of heat)
2
Q
Two types of chemical reaction
A
Exothermic(Give out energy)
Endothermic(Take in energy)
3
Q
What is exothermic?
A
Exothermic reaction give off energy(i.e.temperature rise)
Reactants——>Products + Energy
Products have lower energy than the reactants
4
Q
Which unit is used for energy change?
A
Kilojoule(kJ)
5
Q
What is the sign of the energy in exothermic reaction?
A
Minus
6
Q
Examples of exothermic reactions
A
Cellular respiration
Neutralization of acids by alkalis
combustion of fuels
7
Q
What is endothermic reaction?
A
Endothermic reaction take in energy from their surroundings.
Reactants+energy—->Products
In endothermic reaction,the product has the greater energy than the reactant
8
Q
What is the sign of energy change in endothermic reaction?
A
Plus
9
Q
All of the endothermic reactions are spontaneous. True or False?
A
False,some are spontaneous but most requires energy must be supplied to start the reaction and keep it going
10
Q
Examples of endothermic reactions
A
Cooking
Photosynthesis
11
Q
Breaking bond______
A
require energy
12
Q
Making bond____
A
Release energy
13
Q
If the energy required to break the bond is less than the energy released to make the bond,what is the reaction?
A
Exothermic reaction
14
Q
If the energy required to break the bond is greater than the energy released to make the bond,what is the reaction?
A
endothermic
15
Q
What is bond energy?
A
The energy required to break bond or released energy when these bonds form.
16
Q
Unit of bond energy
A
kJ/mole
17
Q
What is fuel?
A
A substance that provide energy
18
Q
Fossil fuels
A
Coal
Petroleum
Natural gas(CH4)
19
Q
Nuclear fuel
A
They are not burned and contain radioisotope to release energy
20
Q
Most common type of nuclear fuel
A
Uranium-235
21
Q
What is electricity?
A
Form of energy is a current of electron .
22
Q
Reactivity series
A
Please Stop Calling Me A Careless Zebra Instead Learn How Copper May Save Gold
K
Na
Ca
Mg
Al
C
Zn
I
Ph
H
Cu
Mg
Ag
Au
23
Q
What contains in simple cell?
A
Two metals and electrolyte
Negative pole(e flow),
Positive pole
electrolytes
24
Q
Negative pole is made of more reactive metal or less reactive metal?
A
More reactive metal
25
what instrument is used to measure voltage?
Voltmeter
26
Hydrogen fuel cell
Negative pole(donate e)
Positive pole(accept e)
Electrolyte(Contains OH- ion)
Both pole are made of carbon
Negative pole is surrounded by H2 and positive pole is surrounded by O2
27
Water in Cu2SO4 is called
Water of crystallization
28
What is hydrated molecule?
It has water molecules in its structure
29
What is anhydrous molecule?
There is no water in its structure
30
What is reversible reaction?
Contains forward reaction and backward reaction
exothermic reaction in one direction and endothermic reaction in other.The same amount of energy is transferred each time.
31
Important reversible reactions
N2+3H2—->2NH3 (ammonia is used to make nitric acid and fertilizer)
2SO2+O2——>2SO3 ((Manufacture of sulfuric acid)
CaCO3——>CaO+CO2(thermal decomposition reaction CaO=Lime stone has many uses)
32
What is dynamic equilibrium?
Equilibrium means no overall change
Dynamic means continual change occurs
In a closed system,a reversible reaction reaches at a state of dynamic equilibrium,where the forward reaction and reverse reaction takes place at same rate.So there is no overall change.
33
How to shift equilibrium?
1)Change the temperature
2)Change the pressure
3)Remove the product
4)Adding a catalyst
34
Shifting equilibrium of reversible reaction in GASES
1)Forward reaction——>exothermic
Increase in temperature will decrease the product
2)Forward reaction——->Endothermic
Increase the temperature will increase the product
3)Increase the pressure will increase the product due to the more contacts between the reactants leading to more collisions
35
What is a catalyst?
A catalyst speed up the forward and backward reaction so the reaction reaches equivalent faster.
But catalyst do not effect the amount of reactant and product
36
Shifting equilibrium in reversible reaction in aqueous solution
By adding more reactant,more products will produced(increasing the concentration)
By changing the temperature .
Increase temperature increases the rate of endothermic reaction
37
A change in temperature always shifts the equilibrium.True or False?
True
38
A change in pressure will always shift the equilibrium.True or False?
False
A change in pressure will shift equilibrium if the number of molecules is different in each side of equation.
39
Raising temperature and pressure only increases the forward reaction.True or false?
False it increases the rate of both forward and reverse reactions
40
Equilibrium can be occurred in both _____ systems and _____chemical systems
Physical Eg.Br2(l)——>Br2(g)
Chemical Eg.H2+ I2——>2HI
41
What is forward reaction?
Reaction from left to right
42
What is reverse reaction?
Reaction from right to left
43
Features of equilibrium
1)Dynamic state
2)Only in closed system
3)Concentration of reactants and products remains constant
4)No change in macroscopic properties
5)Can be reached in both directions
44
Concentration of both reactants and products are equal in equilibrium.True or false?
False
the concentration of reactants and products remains constant but not equal
45
What is equilibrium mixture?
A mixture of products and reactants in closed system at equilibrium
46
What is Equilibrium position ?
Proportion of reactants and products in the equilibrium mixture is called equilibrium position
47
Equilibrium mixture contains predominantly products lies to the_____
Right
48
Equilibrium mixture contains predominantly reactants lies to the_____
left
49
What is Equilibrium constant,Kc?
A number that expresses the relationship between amounts of reactants and products present at the equilibrium in a reversible reaction at given temperature
50
Do Kc value constant?
No,Kc has a fixed value for particular reactions at specific temperature
51
The only thing that can change the value of Kc is
Temperature
52
State equilibrium constant expression
aA+bB——->cC+dD
Kc=[C]c • [D]d / [A]a • [B]b
Product ပိုင်းဝေ/reactant ပိုင်းခြေ
power___eqမှာပါတဲ့coefficient
reactant or productတစ်ခုထက်ပိုရင်မြှောက်
53
High Kc means
Reaction shift to the right,so more products than reactants
54
Low Kc values mean
reaction shift to left,so more reactants than products
55
Can we determine the rate of reaction by the value of Kc?
No,we can only know the equilibrium mixture at the point
56
How can we find reaction quotient,Q?
If the concentration value of reactants and products at certain time is substituted in equilibrium constant expression,we can get the reaction quotient value.
57
What does it mean, the value of Q=Kc?
reaction at the equilibrium,no net reaction occurs
58
What does it mean, the value of Q
Reaction will shift to the right(more product will produced)
59
What does it mean, the value of Q>Kc?
Reaction will shift to the left(more reactants will be formed)
60
What can we know from the value of Q?
The direction of Kc
61
How Kc value is change for inverse reaction?
Inverse reaction,the products as reactants and vice versa. So the equilibrium constant is Kc’
Kc’=1/Kc or Kc^-1
Kc=[C]c • [D]d / [A]a • [B]b
Kc’=[A]a • [B]b/ [C]c •[D]d
62
How Kc value is change if we double the reaction coefficient?
Kc^2
63
How Kc value is change if we tripling the reaction coefficient?
Kc^3
64
How Kc value is change if we half the reaction coefficient?
square root of Kc
65
How Kc value is change if we add 2 reaction?
Kc^i • Kc^ii
66
What is Le Chatelier’s Principle?
When a system at equilibrium is subjected to a change,the system will respond in such a way to minimize the effect of the change
67
How equilibrium change if the concentration of the one of the reactant is increase?
The rate of forward reaction increases and more product will formed
The rate of backward reaction unchanged
Kc value unchanged
68
How equilibrium change if the concentration of the one of the reactant is decrease?
The rate of backward reaction increases and more reactants will formed
The rate of forward reaction unchanged
Kc value unchanged
69
How equilibrium change if the concentration of the one of the product is increase?
The rate of backward reaction increases and more reactants will formed
The rate of forward reaction unchanged
Kc value unchanged
70
How equilibrium change if the concentration of the one of the product is decrease?
The rate of backward reaction decreases and more products will formed
The rate of forward reaction unchanged
Kc value unchanged
71
How increasing pressure effects on equilibrium?
If the product side have less molecules than reactants side,higher pressure will govern the reaction to the right and more product will be formed.
72
How decreasing pressure effects on equilibrium?
If the product side have less molecules than reactants side,lower pressure will govern the reaction to the left and more reactants will be formed.
73
Do Kc value change when presses is applied to the equilibrium?
no Kc value remains constant
74
Do Kc value change if the temperature is changing?
Yes Kc value depends on temperature
75
If the forward reaction is exothermic reaction,how temperature affect on equilibrium?
increase temperature——reaction shift to left and less product is formed(Kc value decreases)
decrease temperature——reaction shift to right and more product is formed(Kc value increases )
76
If the forward reaction is endothermic reaction,how temperature affect on equilibrium?
increase temperature——reaction shift to right and more product is formed(Kc value increases)
decrease temperature——reaction shift to left and less product is formed(Kc value decreases)
77
Increased temperature effects on endothermic and exothermic(Forward reaction only)
Increased temperature in exothermic—-decreased product(Kc decrease)
Increased temperature in endothermic—-decreased product (Kc increases)
78
Do catalyst change the position of equilibrium?
No
79
Do catalyst change the amount of product and reactant?
No
80
Do catalyst change the value of Kc?
No
81
How catalyst work?
lowering the activation energy of equilibrium mixture leading to reach the equilibrium more quickly
82
Equilibrium is changed by
1)Concentrations change
2)Pressure(no of gas molecules ပေါ်မူတည်)
3)Temperature
83
Value of Kc is changed by
Temperature
84
What is Haber process?
Production of ammonia,NH3
85
Haver process equation
N2+3H2____2NH3
86
Haber process is exothermic or endothermic?
Exothermic
87
Which factor can change the Haber reaction?
Concentration
Pressure:product side has less molecules than reactant side
Temperature :Forward reaction exothermic
Catalyst
88
Concentration changes in Haber Process
Remove NH3 so the concentration of reaction decreases that cause more products formation
89
Pressure change in Haber Process
Product side have less molecules than reactants side.So higher pressure will lead to more product formation
2•10^7 Pa is used
90
Temperature Changes in Haber Process
Forward exothermic reaction
So decreasing the temperature will lead to more product formation
450•C is used
91
Catalyst used in Haber Process
Finely divided Iron + Aluminum oxide and magnesium oxide
92
What is Contact process?
Production of sulfuric acid
93
Contact process equation
2SO2+O2____2SO3
94
Contact process is exothermic or endothermic?
Exothermic
95
Which factor can change The Contact Process?
Pressure:product side has less molecules than reactant side
Temperature :Forward reaction exothermic
Catalyst
96
Pressure changes in Contact Process
Product side have less molecules than reactants side.So higher pressure will lead to more product formation
2•10^5 Pa is used
97
Temperature changes in Contact Process
Forward exothermic reaction
So decreasing the temperature will lead to more product formation
450•C is used
98
Catalyst used in Contact Process
Vanadium (V) oxide
