Chemistry: C8 Rates of Reactions

  • Rate of reaction = amount of reactant used / time

  • Rate of reaction = amount of product produced / time

  • Collision theory - a reaction occurs when particles collide at the correct orientation with enough energy

  • Activation energy - the minimal amount of energy required to react

When temperature increases in a reaction

  • Particles vibrate faster, more movement

  • This increases the frequency of collisions and they collide with enough energy to react (include in every answer!!!!) —^

  • Increasing the temperature, increases the rate of reaction

How surface area effects the rate of reaction

  • Increasing surface area, increases the number of reactant atoms exposed

  • This increases the frequency of collisions

  • This increases the rate of reaction

  • concentration - the number of particles in a certain volume

  • Increasing the concentration, increases the number of particles in 1 volume as so increases the frequency of collisions

Calculating Rates Using Tangents

average rate of reaction

  • Find where reaction stops

  • Find it’s 𝑥 and y points

  • Divide 𝑥 over y

rate using tangents

  • Find where you want to measure and draw diagonal line

  • Create triangle and do: change in 𝑥 / change in y

Catalysts

  • Catalysts lower the activation energy required for a reaction, this means that collisions will be more frequently successful

  • Catalysts increase the rate of reaction without being used up themselves. This means that they can be reused

Reversible Reactions

  • Energy can not be created or destroyed in a reaction

  • The amount of energy released in 1 direction must be equal to the energy absorbed in the other direction

  • Dynamic Equilibrium - the rate of formation of formation of products is equal to the rate of formation of reactants

Haber Process - Altering Conditions

  • 2NO2(2 moles) ←→ N2O4(1 mole - fewest moles) = N2O4 = low temp, high pressure, NO2 = high temp, low pressure

  • le chatelier’s principle - the position at equilibrium will shift to oppose a change in condition

Pressure

  • Increasing the pressure favours the side with the fewest moles

Concentration

  • Higher concentration of reactants = more products

  • Higher concentration of products = more reactions

Haber Process

  • The ammonia is removed to encourage the forward reaction