Consider the balanced equation for a reversible reaction below - NSC Physical Sciences - Question 6 - 2017 - Paper 2

The reaction is ENDOTHERMIC.

The equilibrium constant (Kc) increases with an increase in temperature, indicating that the forward reaction is favored at higher temperatures. In an endothermic reaction, adding heat shifts the equilibrium to the right, favoring the production of products (in this case, NO). This means that as temperature rises, the concentration of the products increases relative to the reactants.

Increases

Decreases

To calculate the equilibrium constant (Kc), first convert the masses of reactants into moles:

• Moles of Ti = ( \frac{336\text{ g}}{48 \text{ g/mol}} = 7 \text{ mol} )
• Moles of Cl2 = ( \frac{426\text{ g}}{71 \text{ g/mol}} = 6 \text{ mol} )

At equilibrium, the reaction left 288 g Ti:

• Remaining Moles of Ti = ( \frac{288\text{ g}}{48 \text{ g/mol}} = 6 \text{ mol} )
• Change in Moles of Ti = 1 mol (7 mol - 6 mol)
• Moles of Cl2 consumed = 2 mol x 1 mol = 2 mol
• Remaining Moles of Cl2 = 6 mol - 2 mol = 4 mol

The equilibrium concentrations:

• [Cl2] = ( \frac{4 \text{ mol}}{2 \text{ dm}^3} = 2 \text{ mol/dm}^3 )
• [TiCl4] = ( \frac{2 \text{ mol}}{2 \text{ dm}^3} = 1 \text{ mol/dm}^3 )

Thus, the Kc expression is:

$K_c = \frac{[TiCl_4]}{[Cl_2]^2} = \frac{1}{(2)^2} = 0.25$

Remains the same