6.2.2 and 6.2.3

6.2.2 Define the term activation energy, Ea.

6.2.3 Describe the collision theory.


1) The more frequent the collisions the faster the reaction.
2) In order to react, particles must have a minimum kinetic energy in order to overcome the repulsion between molecules and to break bonds become reacting to become products.
3) If the molecules dont react in appropriate orientation, a reaction wont take place.

Activation energy	Activation energy is the minimum value of kinetic energy which particles must have before they are able to react.
Three factors that affect the rate of reaction:	1)      Collision frequency
	2)      Number of particles having greater kinetic energy than activation energy
	3)      Appropriate collision geometry

6.2.1

6.2.1 Describe the kinetic theory in terms of the movement of particles whose average energy is proportional to temperature in Kelvin.

 I can describe kinetic theory:

Temperature is kelvins is proportional to the average kinetic energy of the particles in a substance. Basically, kinetic energy is the reason particles are able to move randomly.

The picture shows a kinetic theory apparatus. The kinetic theory apparatus has two cardboard pieces which represents volume and beads that are given energy by increasing the voltage. Increasing the voltage is an analogy of increasing the temperature. As the temperature is increased, particles have more kinetic energy therefore move faster and collide with the insides of the container and cardboard more often causing the cardboard pieces to go up. This shows an increase in volume.

6.1.3

6.1.3: Analyse data from rate experiments. Graphs of changes in concentration, volume or mass against time should be interpreted qualitatively.

6.1.2

6.1.2 Describe suitable experimental procedures for measuring rates of reactions

Experimental Method	Dependent and Independent variables	Diagram	Additional Notes
Change in volume of gas produced	Independent: time (sec) Dependent: volume of gas (cm3)		Gas syringe best because inverted measuring cylinder or burette limited to gases with low solubility
Change in mass	Independent: time(sec) Dependent: mass of reactants(g)		Unlikely to work well, because there might not be a significant decrease in mass for example hydrogen is too light
Change in transmission of light: colorimery/ spectrophotometry	Independent: time(sec) Dependent: light intensity		Only works with coloured compounds, as the concentration of compounds increases, more light is absorbed therefore less is transmitted
Change in concentration measured using titration	Independent: time(sec) Dependent: concentration (cm3)		It cannot be done continuously thus samples must be taken from the reaction mixture. To avoid the mixture over reacting, a method called “quenching” can be used which provides a snap shot at the moment it is withdrawn.
Change in concentration measured using conductivity	Independent: time(sec) Dependent: electrical conductivity		As reactants are converted into products, there’s a sharp decrease in the electricity conductivity as there’s a decrease in the concentration of ions
Non-continuous methods of detecting change during a reaction:”clock reactions”	Independent: time(sec) Dependent: a magnesium ribbon disappearing or a cross view is no longer visible		It is more convenient to measure the time it takes for a reaction to reach a choosen fixed point

6.1.1

6.1.1 Define the term rate of reaction

rate of reaction-the rate of a chemical reaction is an increase in concentration of products to reactions per unit time

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