Rates

What is collision theory

The idea that reactions only happen when particles collide. They have to collide in a certain way for it to occur

What 2 overarching factors are needed to increase a reactions rate

The frequency of collisions

The energy transferred during s collision

What are the 5 main factors to increase the rate

Temp

Concentration

Surface area

Pressure

Catalyst

Explain temperature as a factor affecting rate

As temp increases, particles have more kinetic energy so they move faster and collide more frequently. They are more likely to exceed the activation energy when they collide. More frequent successful collisions

Explain concentration as a factor affecting rate

More particles in a set volume, the more likely they are to collide, therefore more frequent collisions

Explain surface area as a factor affecting rate

More particles are available to react with a higher surface area so more frequent collisions

Explain pressure as a factor affecting rate

More particles in a set volume, the more they are likely to collide, therefore more frequent collisions

Explain catalysts as a factor affecting rate

Provides an alternative route with a lower activation energy, therefore when they collide, they are more likely to exceed the activation energy and react

What is the general equation for rate

Amount of reactant used/amount of product formed

÷

Time taken

How do you work out the rate at a specific time

Use a tangent and measure it’s gradient

Why does a rate graph level out after a while

The reactants have fully reacted

What does a rate graph with a catalyst look like

Steeper over all gradient. Levels off faster

Catalysts are _______ after a reaction

Unchanged

What usually happens to catalysts during a reaction

They react and then are remade

What materials are catalysts often made of

Transition metals or their compounds

What do catalysts do that speeds up the reaction

They provide a surface for the reactants to bond temporarily before becoming products

Catalysts that slow reactions are called ….

Inhibitors

Biological catalysts are…..

Enzymes