Equilibrium

Question 1

What is a volatile liquid?

Answer 1

a liquid that is easily evaporated at room temp.

Question 2

Equilibrium must occur in a CLOSED system

Answer 2

that’s a fact. read it again.

Question 3

describes what happens at equilibrium

Answer 3

the rate of the forward reaction is equal to the rate of the reverse reaction

Question 4

What is the forward reaction?

Answer 4

reactants to products

Question 5

What is the reverse reaction?

Answer 5

products to reactants

Question 6

True or false:

Concentrations of reactant and product are constant, but not necessarily equal, at equilibrium.

Answer 6

True.

Question 7

Formula for equilibrium constant K.

Given aA + bB = cC + dD

Answer 7

[C]^c[D]^d / [A]^a[B]^b

Question 8

Compare and contrast a high value of the equilibrium constant with a low

Answer 8

High levels: Proportionably more product than reactant; lies to the right; reaction is almost to completion

Low level: Proportionally less product to reactant; lies to the left; reaction has barely taken place.

Question 9

What is Le Chatelier’s principle?

Answer 9

It states that a system at equilibrium when subjected to a change will respond in such a way as to minimize the effect of the charge.

Whatever you do to the system will respond in the opposite way.

Question 10

In terms of concentration, according to LCP, what shifts the equilibrium to the right?

Answer 10

Increase of concentration of reactant; decrease of concentration of product.

equilibrium constant will remain the same.

Question 11

In terms of concentration, according to LCP, what shifts the equilibrium to the left?

Answer 11

Decrease of concentration of reactant; increase of concentration of product.

equilibrium constant will remain the same.

Question 12

What happens to system in terms of pressure? (according to LCP)

Answer 12

ONLY FOR GASEOUS MOLECULES

Increase in pressure will move the equilibrium to the side with a smaller number of molecules.

Decrease in pressure will cause a shift in the side with a larger number of molecules.

equilibrium constant will remain the same.

Question 13

What happens to the system in terms of temperature?

Answer 13

Well the equilibrium constant does not remain constant.

If the temperature DECREASES

• Exothermic
  
  • Equilibrium constant will increase.
  • Equilibrium will shift to the right.
• Endothermic
  
  • Equilibrium will shift to the left
  • Equilibrium constant will decrease

If the temperature INCREASES

• Exothermic
  
  • Equilibrium will shift to the left
  • Equilibrium constant will decrease
• Endothermic
  
  • Equilibrium constant will increase.
  • Equilibrium will shift to the right.

Question 14

What does a catalyst do for the system?

Answer 14

Just speeds up rate of reaction. Nothing else. Just that.

Question 15

What is the Haber Process and why is it beneficial?

Answer 15

Production of ammonia.

N2 (g) + 3H2 (g) = 2NH3 (g)

Maximizes production with efficiency.

• All products are gases. High pressure rule applies. (more pressure more product)
• Forward is exothermic typically favored by low temperature. Because low temp causes slow rate, a moderate temp is used.
• AS ammonia is formed it is taken out (decrease of concentration on the right) this increases yield of products.
• Sped up using iron as catalyst.

Question 16

What is the Contact process?

Answer 16

Production of ammonia.

1. Combustion of sulfur
2. Oxidation of sulfur dioxide
3. Combination of sulfur trioxide with water.

2 is important because it is most applicable to LCP.

• Pressure: 2 atm. More product yielded.
• Temp: Exothermic. Low temp will increase yield, but lower rate (450 C)
• catalyst increases rate of reaction. (vanadium (V) oxide)