Equilibrium

Which statements about an isolated system at equilibrium are always correct?

I. Energy cannot enter or leave the system

II. None of the products can escape

III. The concentrations of the reactants and products are equal

• I and II only

• I and III only

• II and III only

• I, II and III

Which will give an increased yield of ammonia in the equilibrium reaction for the Haber Process?

Hydrogen (g) + nitrogen (g) ⇌ ammonia (g) ∆H = – 92 kJ

I. Using iron metal with a high surface area as catalyst

II. Decreasing the temperature

III. Increasing the pressure

• I and II only

• I and III only

• II and III only

• I, II and III

The value for the equilibrium constant reaction

2SO2(g) + O2(g) ⇌ 2SO3(g)

is 4.0 x 10^24 at 298K. What would be the value for the equilibrium constant for the following reaction at the same temperature?

2SO3(g) ⇌ 2SO2(g) + O2(g)

• 2.0 x 10^12

• 2.5 x 10^-25

• 4.0 x 10^24

• 2.0 x 10^24

What will be the effect on the value of Kc and the position of equilibrium when the

temperature is decreased in the following reaction?

3H2(g) + N2(g) ⇌ 2NH3(g) ΔH = – 92 kJ

• Kc Increases and Moves to give more products

• Kc Increases and Moves to give more reactants

• Kc Decreases and Moves to give more products

• Kc Decreases and Moves to give more reactants

Which will affect the value of Kc in the following reaction?

2NO2(g) ⇌ N2O4(g) ΔH = – 24 kJ

• Adding some NO2(g) to the equilibrium mixture.

• Lowering the pressure.

• Adding a catalyst.

• Raising the temperature.

The equilibrium between nitrogen dioxide (dark brown) and dinitrogen tetroxide (colorless) is represented by the following equation.

2NO2(g) ↔ N2O4(g) ∆H = negative ; Kc = 1 at 328K

Two moles of NO2(g) and two moles of N2O4(g) were placed in an empty 1 dm3 container and allowed to come to equilibrium at 328 K. Predict to the value of Kc, if the temperature increase.

(one word only)

The equation for the decomposition of hydrogen iodide is

2HI(g) ⇌ H2(g) + I2(g) ΔHӨ = +52 kJ

identify the value of Kc. the Hydrogen iodide have 0.06M at the initial and 0.02M hydrogen gas at the equilibrium.