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equilibrium concept
equlibrium expression
calculation
equilibrium factors
100

Chemical equilibrium is a state in which the rate of the forward reaction _________ to the rate of the backward reaction

equals

100

2SO2(g) + O2(g) ⇋ 2SO3(g)

[SO3]2/[SO2]2[O2]

100

An equilibrium mixture is analyzed and found to contain 0.62 mol dm-3 N2, 0.50 mol dm-3 H2, and 0.24 mol dm-3 NH3. 

What is Kc for the following reaction? 

N2(g) + 3H2(g) ⇋ 2NH3(g)

0.74

100

For the following equilibria would you increase or decrease the temperature to force the reaction in the forward direction? 

H2(g) + CO2(g) ⇋ H2O(g) + CO(g) (delta)H = +41.0 kJ

increase

200

In some reactions, the reactants form products and the product can change back into reactants. This type of reactions are called __________ reactions.

reversible

200

2CO(g) + O2(g) ⇋ 2CO2(g)

K= [CO2]2/[CO]2 [O2]

200

Given the following reaction:

PCl3 + Cl2 ⇋ PCl5  K = 96.2

At equilibrium [PCl3] is 0.5 mol dm-3, [Cl2] is 0.07 mol dm-3.

What is [PCl5]?

3.4 mol dm-3

200

A catalyst is added to the below reaction. 

2SO2(g) + O2(g) ⇋ 2SO3 (g)

Tell how the equilibrium is affected.

no change

300

Chemical equilibrium is a dynamic process. 

 True/False

True

300

HCN(s) ⇋ H+(aq) + CN-(aq)

[H+][CN-]

300

At a given temperature, an equilibrium mixture of the reaction 

2NO(g) + O2(g) ⇋ 2NO2(g) 

Contains 0.090 moles NO, 0.120 moles of O2, and 0.060 moles of NO2 in a 3.00 liter container. 

Calculate the value of Kc!

11

300

Increasing temperature to the following reaction will shift equilibrium in what direction?

4NH3(g) +5O2(g) ⇋ 4NO(g) + 6H2O(g) + heat

left

400

CaCO3 (s) ⇋ CaO (s) + CO2 (g) is a _____________ equilibrium.

heterogenous

400

3Ca2+(aq) + 2PO4 3+(aq) ⇋ Ca3(PO4)2 (s)

1/[Ca2+]3[PO4 3-]2

400

Given the following reaction:

H2(g) + F2(g) ⇋ 2HF (g)

At 500 0C; [H2] = [F2] = 2.10-2 mol dm-3

[HF] = 4.10-2 mol dm-3

What is Kc ?

Kc = 4

400

Tell how you would change a concentration in order to force the following reaction in the forward direction!

4NH3(g) +5O2(g) ⇋ 4NO(g) + 6H2O(g) + heat

decrease [NO] or [H2O]

increase [NH3] or [O2]

500

Balance the following equation:

BF3 + Li2SO3 ⇋ B2(SO3)3 + LiF

2BF3 + 3Li2SO3 ⇋ B2(SO3)3 + 6LiF

500

BF3(aq) + Li2SO3(aq) ⇋ B2(SO3)3(aq) + LiF(s)

[B2(SO3)3]/[BF3]2[Li2SO3]3

500

Given the following reaction:

2XY(g) ⇋ X2(g) + Y2(g)

Initial the reaction starts with 0.8 mole XY at 250 0C in a 2 dm-3 container. At equilibrium, there is 0.2 mole Y2(g). 

 What is Kc?

Kc = 0.25

500

How would you change the pressure of the system in order to shift the equilibrium of the following reaction in the reverse direction?

4NH3(g) +5O2(g) ⇋ 4NO(g) + 6H2O(g) + heat

increase pressure