C10 Rates of reaction

How is a reaction where gas is produced normally monitored

Rate of gas release (evolution) - gas syringe/inverted measuring cylinder

Alternative method for measuring reaction where gas is produced

Open container on electronic balance - rate of mass lost

How can reaction where precipitate is formed be monitored

Time taken for cross to disappear

In reaction where precipitate is formed, what is the time taken for cross to disappear related to

Proportional to rate of reaction

How to monitor iodine clock reaction

Time taken for starch indicator to turn blue-black

How to monitor reaction where chemicals form coloured solution

Time taken for solution to turn that colour

Time taken for solution to turn a certain colour is proportional to

Rate of reaction

Change in pH, change in temperature and change in colour are all

Physical properties that can be used to monitor rate of chemical reaction

How to calculate rate of reaction from graph of change of reactant/product against time

Calculate gradient of tangent

What is rate of reaction measured in

Change in reactant/product per unit time

Activation energy

Minimum amount of energy for particle to successfully react upon collision

What do particles need to do/have to react

Collide at correct orientation with sufficient energy

Temp, SA (solids), conc (solutions), pressure (gas) are all examples of

Factors which affect rate of reaction

What affects rate of reaction for solutions

Temp, conc

What affects rate of reaction for gases

Temp, pressure

What affects rate of reaction for solid reactants/catalysts

Temp, SA

Why are most reactions faster at higher temp

More Ek → more frequent collisions ; more likely to possess Ea

Why does a higher concentration of solution increase RoR

More particles per unit volume - more frequent collisions

Why does higher pressure increase rate of reaction in gas

More particles per unit volume - more frequent collisions

Why does higher surface area increase rate of reaction

More particles exposed for reaction - more frequent collisions

If a cube is split into 4 smaller cubes, what happens to total SA

Doubles

ΔH for exothermic reaction

Negative

What is a catalyst

Alters rate of chemical reaction without being used up or chemically altered itself

How does a catalyst work

Provides alternative reaction pathway with lower activation energy

How does a catalyst affect reversible reaction equilibrium position

Equilibrium is reached faster but equilibrium position doesn’t shift

Why does a catalyst not affect equilibrium position of reversible reaction

Increases rate of forward and backward reaction by the same amount

How does catalyst affect overall yield of reversible reaction

No effect

What is activation energy on an energy profile diagram

Arrow from reactant energy to top of peak

What is enthalpy change in reactant profile

Arrow from reactant energy to product energy