Unit 5 - Chemical Equilibrium Flashcards

1
Q

T/F
Most chemical reactions are irreversible. Only few reactions proceed to completion.

A

F

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2
Q

It exists when two opposing reactions occur simultaneously at the same rate.

A

Chemical equlibrium

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3
Q

It is a dynamic process.

A

Chemical equilibrium

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4
Q

T/F
Once equilibrium is achieved, the amount of each reactant and product remains constant.

A

T

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5
Q

T/F
As a system approaches equilibrium, both the forward and reverse reactions are occuring.

A

T

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6
Q

All reactants and products are in same phase and cannot be separated.

A

Homogenous equilibrium

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7
Q

Reactants and products are not in homogenous phase and can be separated.

A

Heterogenous equilibrium

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8
Q

T/F
The forward rate will be the reactant side.

A

T

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9
Q

T/F
The reverse rate will be the product side.

A

T

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10
Q

States that the rate of any chemical reaction is proportional to the product of the masses of the reacting substances, with each mass raised to a power equal to the coefficient that occurs in the chemical equation.

A

Law of mass action

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11
Q

It relates the concentrations of reactants and products at equilibrium.

A

Equilibrium constant

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12
Q

T/F
It is the product of the concentrations of PRODUCTS of a chemical equilibrium divided by the concentrations of REACTANTS, each raised to the power equal to its coefficient in the balanced chemical equation.

A

T

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13
Q

T/F
In writing equilibrium constant expression, a pure solid or a pure liquid in the reaction is omitted from the expression.

A

T

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14
Q

T/F
The concentration of a pure solid or a pure liquid is always the same.

A

T

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15
Q

The activity of liquid or solid is defined as _____.

A

1

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16
Q

T/F
H2O(l) has activity of 1 while H2O(g) is considered in the expression.

A

T

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17
Q

This results from a reversible reaction involving reactants and products that are in different phases.

A

Heterogeneous equilibrium

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18
Q

T/F
In heterogeneous equilibrium, neither density nor molar mass is a variable, the concentrations of solids and pure liquids are constant.

A

T

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19
Q

T/F
The concentrations of pure liquids and pure solids are not included in equilibrium constant expressions.

A

T

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20
Q

The larger K the more _____ are present at equilibrium.

A. Reactants
B. Products

21
Q

The smaller K the more _____ are present at equilibrium.

A. Reactants
B. Products

22
Q

If K > 1, then products dominate at equilibrium and equilibrium lies to the _____.

A. Left
B. Right

23
Q

If K < 1, then products dominate at equilibrium and equilibrium lies to the _____.

A. Left
B. Right

24
Q

If K > 1, the reaction is _____.

A. Product-favored; product predominates at equilibrium.
B. Reactant-favored; reactant predominates at equilibrium

25
If K < 1, the reaction is _____. A. Product-favored; product predominates at equilibrium. B. Reactant-favored; reactant predominates at equilibrium
B
26
T/F In the magnitude of equilibrium constants, an equilibrium can be approached from any direction.
T
27
The ___ for a reaction in one direction is the reciprocal of the equilibrium constant of the reaction in the opposite direction.
Kc
28
It is the equilibrium constant for a net reaction made up of two or more steps is the product of the equilibrium constants for the individual steps.
Multiple equilibria
29
T/F In predicting the direction of the reaction, the reaction quotient, Q, for a reaction at conditions NOT at equilibrium.
T
30
T/F Q = K only at equilibrium.
T
31
If K = Q the _____. A. System is at equilibrium. B. Forward reaction is favored. C. Reverse reaction is favored.
A
32
If K > Q the _____. A. System is at equilibrium. B. Forward reaction is favored. C. Reverse reaction is favored.
B
33
If K < Q the _____. A. System is at equilibrium. B. Forward reaction is favored. C. Reverse reaction is favored.
C
34
T/F Changes in experimental conditions may disturb the balance and shift the equilibrium.
T
35
Factors that affect equilibrium.
Concentration Catalyst Temperature Volume and Pressure
36
A principle wherein if stress is applied to a system that is in equilibrium, the system will adjust in such a way that the stress is partially offset as the system reaches a new equilibrium position.
Le Chatelier's Principle
37
A + B ⇋ C + D Increasing the amount of A or B. A. Forward B. Reverse C. No shift
A
38
A + B ⇋ C + D Increasing the amount of C or D. A. Forward B. Reverse C. No shift
B
39
A + B ⇋ C + D Decreasing the amount of A or B. A. Forward B. Reverse C. No shift
B
40
A + B ⇋ C + D Decreasing the amount of C or D. A. Forward B. Reverse C. No shift
A
41
A + B ⇋ C + D Reacting A with compound E. A. Forward B. Reverse C. No shift
B
42
A + B ⇋ C + D Removing C as the reaction proceeds. A. Forward B. Reverse C. No shift
A
43
A system that RELEASES heat to the surroundings, has a negative ΔH (-ΔH) by convention, because the enthalpy of the products is LOWER than the enthalpy of the reactants of the system.
Exothermic reaction
44
A system of reactants that ABSORBS heat from the surroundings in a reaction has a positive ΔH (+ ΔH), because the HIGHER of the products is HIGHER than the enthalpy of the reactants of the system.
Endothermic reaction
45
Changes in volume and pressure affect only systems involving _____. A. Solid B. Liquid C. Gases
C
46
T/F Changes in volume and pressure increase in pressure or decrease in volume favors the reaction where there is less total number of moles of gases.
T
47
T/F Changes in volume and pressure decrease in pressure or increase in volume favors the reaction where there is higher total number of moles of gases.
T
48
T/F Presence of catalyst does not affect the state of equilibrium.
T
49
T/F Presence of catalyst allows the system to reach equilibrium faster.
T