Chemical Equilibrium

An equilibrium constant with a value of 4.6 x 10¹⁵ indicates that at equilibrium

• the reactants are favored.

• the products are favored.

• approximately equal concentrations of reactants and products are present.

Tags

NGSS.HS-PS1-6

When pressure decreases, in which direction does the equilibrium shift?

• The equilibrium shifts in the direction that increases the number of moles of gas.

• The equilibrium shifts in the direction that decreases the number of moles of gas.

• The equilibrium does not shift.

• The equilibrium shifts always shifts to the right.

• The equilibrium shifts always shifts to the left.

For an endothermic reaction, increasing the temperature

• does not shift the equilibrium since K is a constant.

• increases the rate of the reverse reaction to form more reactants.

• increases the rate of the forward reaction to form more products.

• increases the rate of the reverse reaction to form more products.

Tags

NGSS.HS-PS1-5

For which of the following reactions does Kp = Kc?

• 3Fe(s) + 4H₂O(g) ⇌ Fe₃O₄(s) + 4H₂(g)

• C(s) + H₂O(g) ⇌ CO(g) + H₂(g)

• 2SO₂(g) + O₂(g) ⇌ 2SO₃(g)

• H₂(g) + I₂(s) ⇌ 2HI(g)

What is the value for Kc if [CO] = 0.025, [H₂] = 0.013 and [CH₃OH] = 0.0028 for the following reaction?

CH₃OH(g) ⇌ CO(g) + 2 H₂(g)

• 0.12

• 9.1 × 10^-7

• 6.6 × 10²

• 1.5 × 10^-3

• 8.6

Tags

NGSS.HS-PS1-6

Which of the following substances present in the chemical reaction would NOT be included in the equilibrium constant expression?

• solvents

• NaCl(s)

• H₂O(l)

• NH₄Cl(s)

• all of these

For the following chemical equilibrium, Kp = 4.6 × 10^-14 at 25 °C, find the value of Kc for this reaction at 25 °C.

2 Cl₂(g) + 2 H₂O(g) ⇔ 4 HCl(g) + O₂(g)

• Kc = 2.2 × 10^-14

• Kc = 4.6 × 10^-14

• Kc = 9.4 × 10^-14

• Kc = 1.9 × 10^-15

• Kc = 1.1 × 10^-12

For the reaction PCl₅ (g) → PCl₃ (g) + Cl₂ (g) Kc = 0.0454 at 261°C. If a vessel is filled with these gases such that the initial concentrations are [PCl₅] = 0.25M, [PCl₃] = 0.20 M, and [Cl₂] = 2.25 M, in which direction will a reaction occur and why?

• toward products because Q = 0.56

• toward reactants because Q = 1.8

• it is at equilibrium

• toward reactants because Q = 0.0454

• toward products because Q = 2.8

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-6

Consider the following reaction.

C(s) + H₂O(g) ⇌ CO(g) + H₂(g)

At equilibrium at a certain temperature, [H₂O(g)] = 0.12 M, and [CO(g)] = [H₂(g)] = 1.2 M. If suddenly these concentrations are increased by 0.50 M, which of the following is true?

• Since Kc does not change, nothing happens.

• more products are formed

• more H₂O(g) will be formed

• Kc = 4.66

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-6

Then notation [A]⁴ is equivalent to which of the following?

• [A] + [A] + [A] + [A]

• [A] × [A] × [A] × [A]

• 1/([A] + [A] + [A] + [A])

• 1/([A] × [A] × [A] × [A])