Topic 7 SL Chemistry Equilibrium

What effect does increasing both pressure and temperature have on the equilibrium constant, K_c?

N₂ (g) + 3H₂ (g) ⇌ 2NH₃ (g) ΔH = −45.9 kJ

• Decreases

• Increases

• Remains constant

• Cannot be predicted as effects are opposite

What will happen if the pressure is increased in the following reaction mixture at equilibrium?

CO₂ (g) + H₂O (l) ⇌ H⁺ (aq) + HCO₃⁻ (aq)

• The equilibrium will shift to the right and pH will decrease.

• The equilibrium will shift to the right and pH will increase.

• The equilibrium will shift to the left and pH will increase.

• The equilibrium will shift to the left and pH will decrease.

Consider the equilibrium between N₂O₄(g) and NO₂(g).

N₂O₄(g) ⇌ 2NO₂(g) ΔH = +58 kJmol⁻¹

Which changes shift the position of equilibrium to the right?

I. Increasing the temperature

II. Decreasing the pressure

III. Adding a catalyst

• I and II only

• I and III only

• II and III only

• I, II and III

Tags

NGSS.HS-PS1-5

What is the equilibrium constant expression, K_c, for the following reaction?
 $2NH_3\left(g\right)+2O_2\left(g\right)\ \leftrightarrow\ 2N_2O_4\left(g\right)+3H_2O\left(g\right)$  

• $\frac{3\left[H_2O\right]\left[N_2O\right]}{2\left[NH_3\right]2\left[O_2\right]}$

• $\frac{\left[NH_3\right]^2\left[O_2\right]^2}{\left[N_2O\right]\left[H_2O\right]^3}$

• $\frac{2\left[NH_3\right]2\left[O_2\right]}{3\left[H_2O\right]\left[N_2O\right]}$

• $\frac{\left[N_2O\right]\left[H_2O\right]3}{\left[NH_3\right]\left[O_2\right]^2}$

The enthalpy change for the dissolution of NH₄NO₃ is +26 kJ mol^–1 at 25 °C. Which statement about this reaction is correct?

• The reaction is exothermic and the solubility decreases at higher temperature.

• The reaction is exothermic and the solubility increases at higher temperature.

• The reaction is endothermic and the solubility decreases at higher temperature.

• The reaction is endothermic and the solubility increases at higher temperature.

Tags

NGSS.HS-PS1-5

Which variable affects the equilibrium constant, K_c?

• Atmospheric pressure

• Catalyst

• Concentration of reactants

• Temperature

What is the effect of increasing temperature on the equilibrium?
 $ClNO_2\left(g\right)\ +\ NO\left(g\right)\ \leftrightarrow\ ClNO\left(g\right)\ +\ NO_2\left(g\right)$ 
 $\Delta H\degree\ =\ -18.4kJ$  

• A

• B

• C

• D

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-6

What happens when the temperature of the following equilibrium system is increased?

CO(g) + 2H₂(g) CH₃OH(g) ΔH^θ = -91kJ

• A

• B

• C

• D

Tags

NGSS.HS-PS1-5

Carbon monoxide and water react together in the industrial production of hydrogen gas.
 $CO\left(g\right)+H_2O\left(g\right)\leftrightarrow CO_2\left(g\right)+H_2\left(g\right)$  
What is the impact of decreasing the volume of the equilibrium mixture at a constant temperature?

• The amount of hydrogen gas remains the same but its concentration decreases
  

• The forward reaction is favored

• The reverse reaction is favored
  

• the value of KC remains unchanged
  

Tags

NGSS.HS-PS1-5

What is the equilibrium constant expression, for the formation of hydrogen iodide from its elements?
 $H_2\left(g\right)+I_2\left(g\right)\leftrightarrow2HI\left(g\right)$  

•  $K_C=\frac{\left[HI\right]^2}{\left[H_2\right]x\left[I_2\right]}$  

•  $K_C=\frac{\left[2HI\right]}{\left[H_2\right]+\left[I_2\right]}$  

•  $K_C=\frac{2\left[HI\right]^2}{\left[H_2\right]+\left[I_2\right]}$  

•  $K_C=\frac{\left[2HI\right]}{\left[H_2\right]x\left[I_2\right]}$  

Tags

NGSS.HS-PS1-6