 VIEW IN FULL SCREEN

# Edexcel A-level Chemistry Rates and equilibrium At equilibrium, the concentrations of the products and reactants will be constant but not equal. Kc is the equilibrium constant, expressing these equilibrium concentrations combined.

aA + bB ⇌ cC + dD Equilibrium constants can be explained in terms of partial pressures of gases, Kp. It can be expressed from the equation for a reversible reaction.

aA + bB ⇌ cC + dD Rate equations describe the rate of reaction in terms of concentration and order of the reaction with respect to each reactant. The rate constant k varies depending on the reaction. The rate of a chemical reaction can be increased by increasing temperature, increasing reactant concentration, increasing the surface area of solid reactants or the use of catalysts. There are a number of ways we can determine the rate of reaction experimentally. The rate constant for a reaction various with temperature and activation energy. This is shown by the Arrhenius equation. # ✅

How can the equilibrium constant of a system at equilibrium be altered? # ✅

For an equilibrium, where 1.3 x 10⁻² mol l⁻¹ of 2SO₂ is reacted with 2 x 10⁻² mol l⁻¹ O₂ to make 4.75 x 10⁻⁴ mol l⁻¹ 2SO₃, calculate Kc. # ✅

Give the expression for Kp. # ✅

Calculate the partial pressure of each component in an equilibrium system at 75 atm with reactant A mole fraction 0.38, reactant B mole fraction 0.61 and product C mole fraction 0.24. # ✅

Give the expression for Kp for the Haber Process where the reactants are N₂ and 3H₂ and the product is 2NH₃. # ✅

What would the units of a second order rate constant be? # ✅

If the rate of reaction goes from 1.3 mol l⁻¹ s⁻¹ to 5.2 mol l⁻¹ s⁻¹ as the NH₃ concentration is doubled, what is the order of reaction with respect to NH₃? # ✅

Calculate rate constant k when the initial rate of reaction is 4.35 × 10⁻³ mol l⁻¹ s⁻¹ for a reaction between a second order reactant A at concentration 0.20 mol l⁻¹ and a first order reactant B at concentration 0.35 mol l⁻¹. # ✅

What are the units of the rate constant for a third order reaction?. # ✅

What is the gradient of a graph plotted of lnK = lnA - EA/RT?  Have you found the questions useful?