C8 Rates and Equilibium

Monitoring the amount of reactants used up over time Or measuring the amount of products over time

Find the gradient of a line Draw a tangent to the curve

The minimum amount of energy that particles must have in order to react, they must collide with a certain amount of energy before they can react

The rate of a reaction increases if the surface area to volume ratio of the solid reactant increases, this increases the frequency of collisions between the particles

Increase the frequency of reacting particles colliding with eachother Increase the energy they have when they collide Increase surface area : volume ratio to increase frequency of collisions

Mass of reactant used up (g)/ time

Increasing the temperature increases the rate of reaction because particles collide more frequent and more energetically. More of the collisions ocurring in a given time results in a faster reaction because a higher proportion of particles have energy greater than the activation energy

Infreasing the concentration of reactants in solution increases the frequency of collisions between particles and so increases rate of reaction

Increasing the pressure of reacting gases increases the frequency of collisions because the gas particles are moving faster this increases the rate of reaction

Relights a glowing splint

A chemical substance that speeds up a chemical reaction by decreasing the activation energy. It is not used up itself during the reaction

Catalysts used in chemical plants can become ‘ poisoned ‘, and not work anymore. This happens because impurities in the reaction mixture combine with the catalyst and stop it working

They increase the rate of reaction and reduce energy costs which maximises profits

We do not include the catalyst as a reactant in a symbol equation, instead it goes above/ below the arrow leading to the products

2H2O2 -(catalyst)–> 2H2O + O2 Catalyst is mangenese dioxide ( MNO2 )

White anhydrous copper sulphate turns blue Cobalt chloride paper turns from blue to pink

Forwards reaction : A+B ⇌ C+D Reverse reaction: C+D⇌A+B

The reaction one way is exothermic and the reverse is endothermic

In any reversible reaction, the amount of energy transferred to the surroundings when the reaction goes one way is exactly equal to the energy transferred back when the reaction goes in the opposite direction

The difference in energy between the reactants and the products will be the same for both directions of the reaction. Reaction profiles can also be used to determine which direction of the reaction is exothermic or endothermic

Equilibrium occurs when the reaction is in apparatus which prevents the escape of reactants and products. Equilibrium is achieved when the forwards and reverse reactions occur at exactly the same rate

If you change a componet in a reaction that is in dynamic equilibrium, the reaction will adjust and shift the position of equilibrium to cancel out the change and return to dynamic equilibrium

If the product of the forwards reaction is decreased, the forwards reaction will increase in rate ( equilbrium shifts ) to make more of the product

If forwards reaction is Exothermic: Increase - less products formed - reaction goes to endothermic to decrease temp( more reactants ) Decrease - more products formed - reaction goes to exothermic to increase temp ( less reactant ) If forwards reaction is Endothermic: Increase - more products formed - reaction goes more endothermic to cool the temperature Decrease - less products formed - reaction goes more exothermic to raise the temperature