rate of reaction- chemistry

Define rate of chemical reaction

How quickly reactants are used uo or products are formed

Mean rate of reaction formula

Products formed / time taken

OR

Reactants used/ time taken

Difference between aqueous and liquid solution

Liquid is melted

Aqueous is dissolved in water

3 ways of measuring RoR

(1) measure the volume of gas formed

(2) measure the mass lost when gas is produced

(3) measure disappearing transparency

How to measure gradient on a curved graph

Tangents then calculate gradient

define limiting factor

The reactant that runs out first- limiting the RoR

Define collision theory

For a chemical reaction to occur particle must collide with activation energy

5 factors that can affect RoR

Concentration

Pressure

Surface area

Temperature

Catalyst

Explain how surface area increase RoR

Increased surface area → more particles available for collision→ frequency of collisions increases→ RoR increases

Explain why increasing concentration increases RoR

More particles in the same volume of a solution → frequency of collisions increases→RoR increases

Explain why higher pressure increases RoR

More crowded particles→frequency of collisions increases→ RoR increases

Define activation energy

The minimum amount of energy needed for particles to react

How do catalysts speed up reactions

Provide an alternative route which requires a lower activation energy