• Concentration
• Temperature
• Catalyst
• Total surface area
• Volume 

• Sampling
  • Taking small samples of the reaction mixture at various times
  • Carry out chemical analysis
  • ‘Quenched’ to stop or slow down the reaction
  • By cooling sample in ice
• Continuous 
  • Physical property of the mixture is monitored over a period of time
  • Colorimetry 
  • Conductivity meter 
  • Changes in pressure and volume
    • Small changes of volume using dilatometer

• Rate of the reaction = k x
• X is the reactant
• K is rate constant
• Can only be determined through experiments
• Not from stoichiometric equations

1. Zero-order reaction k 
   1. No effect towards rate
2. First-order reaction k[R]
   1. Directly proportional
3. Second-order reaction k[R]2
   1. Quadratic curve

1. Zero-order reaction (straight)
2. First-order reaction (curve)
3. Second-order reaction (curve)
   1. Curve for second order is deeper than first order
   2. Curve for the second order has a relative longer ‘tail’ as it levels off
   3. Can distinguish the two curves by determining the successive half-lives

• sampling and continuous method
• finding initial rate (tangent at origin)
• rate equations (cannot use stoichiometric equations)
• order of reaction
• for graph of conc./time, second order has deeper curve and longer tail than first order
• to differentiate between first and second use half life, constant half life means it is first order

• sampling: taking small samples of the reaction mixture at various times
• continuous: physical property of the mixture is monitored over a period of time

• Two types of graph: straight down or curve for reactant-> product

• rate = k[reactant]

• Rate = k
• The rate is zero order with respect to [reactant]^0

• Rate = k[reactant]^1
• The rate is first order with respect to [reactant]^1

• Rate = k[reactant]^2
• The rate is second order with respect to [reactant]^2

• if the graph is steeper, that graph is second order 

1. The factors affecting rate of reaction (temperature, pressure, surface area, presence of catalyst, concentration)
2. Sampling: Small samples obtained while the reaction is quenched to ensure accuracy, and that any retrieval of sample is not impacted by its time interval. The sample is chemically analysed through methods such as titration.
3. Continuous: Physical property of the experiment is monitored without quenching or taking samples. This can be done through colourimetry, electrical conductivity, measuring pressure and volume changes, using gas syringe and dilatometer.
4. Rate of reaction can be measured by drawing tangents to a graph and calculating its gradient.
5. The reaction orders consist mostly of zeroth, first and second order.
6. The rate-concentration graph:

• Zeroth order: Straight horizontal line
• First order: Straight line with (+) gradient passing through O
• Second order: Positive quadratic curve passing through O

• Zeroth order: Straight line with (-) gradient
• First order: Curve with negative gradient with decreasing magnitude, constant half life
• Second order: Similar to first order but starts off more steep and ends at higher [R] value. Half life is not constant but increasing

• sampling method:
• using chemical analysis
• samples are quenched (or slowed down)
• samples are taken at intervals throughout the progress of the reaction
• continuous method:
• monitor the reaction over a period of time
• can use colorimetry, electrical conductivity, gas syringe, dilatometer
• graphs (rate vs time graphs)
• zero order (horizontal line) , rate is the same
• first order (straight line diagonally), rate is directly proportional to concentration 
• second order (curve), rate is directly proportional to concentration squared.
• graphs (concentration vs time graphs)
• zero order (straight line going down diagonally)
• first order (curve)
• second order (steeper curve)

• create a concentration-time graph 
• draw a tangent to the curve and find gradient with it
• initial rate follows the tangent, not the graph itself

• temperature 
• catalyst 
• concentration 
• total surface area
• pressure

change in concentration/time taken for this change 

• concentration

• pressure 

• temperature

• surface area

• catalyst

• sampling 

• continuous 

• take small samples of the reaction mixture at various times

• chemical analysis will be carried out

• "quenched", so stop or slow down reaction by cooling sample in ice

• the physical property of the mixture is monitored over a period of time

• uses colorimetry, conductivity meter, changes in pressure and volume so gas syringe or dilatometer will be used

• rate = k[reactant], where k is the rate constant

• the equation can only be derived experimentally by calculating how the concentration of the reactants affects the rate of reaction, and not from its stoichiometric equations

• learnt how to derive rate equations

• zero order ( with respect to [reactant]^0 )

• first order  ( with respect  to [reactant]^1 ) 

• second order ( with respect  to [reactant]^2 ) 

• zero order ( straight horizontal line )

• first order  ( straight line passing through origin ) 

• second order ( quadratic curve ) 

• zero order ( constant rate of decline )

• first order  ( declines in a shallow curve ) 

• second order ( a deeper curve than first order ) 

• time taken for concentration of a reactant to become half of its original value

• first order has a constant half-life, so easier to differentiate between first order and

1. Sampling
   • samples are taken at intervals of time
   • involves chemical analysis
   • reaction needs to be "quenched" with ice or cold water
2. Continuous
   • changes in physical characteristics are observed
   • measuring changes in colour, electrical conductivity, volume, or gas pressure
   • conducting colorimetry, using electrical conductivity meter, dilatometer, or gas syringe

• concentration-time graph
• creating a tangent
• measure gradient by making a large triangle with the tangent
• for initial rate make sure it's a tangent, not a line that intersects the curve

1. Zero Order
   • rate-concentration graph is horizontal line across
   • concentration-time graph is straight line
   • half-life is decreasing
   • k
   • independent of the concentration of the specified reactant
2. First Order
   • rate-concentration graph is a straight line 
   • concentration-time graph is a curve
   • half-life is constant
   • k[R]
   • dependent on the concentration of the specified reactant 
3. Second Order
   • rate-concentration graph is a quadratic curve/parabola
   • concentration-time graph is a curve
   • half-life is increasing
   • k[R]²
   • dependent on the square of the concentration of the specified reactant

• cannot be determined by stoichiometric equations
• determine through experimentation
• rate=k[R] where k is the rate constant and [R] is the concentration of the reactant
• rate determining step in a multistep reaction is always the slow step
• depends on reactants, not products

• Concentration
• Pressure
• Surface area
• Temperature
• Catalyst

• Rate against concentration graph: horizontal line
• Concentration against time graph: straight line with negative gradient, half life is decreasing
• Its rate is independent of the concentration 

• Rate against concentration graph: straight line passing through origin 
• Concentration against time graph: curve with negative and decreasing gradient, constant half life
• Its rate is directly proportional to the concentration

• Rate against concentration graph: positive quadratic curve 
• Concentration against time graph: curve with negative gradient, half life is increasing
• Its rate is directly proportional to the square of concentration