rate of reaction

Question 1

what is collision theory

Answer 1

chemical reaction occur when reactants collide successfully for a collision to be successful, the reactant particles must collide with correct orientation which is greater than or equal too activation energy of reactant

Question 2

what effects collision theory

Answer 2

• temperature
• pressure
• surface area
• addition of a catalyst

Question 3

how does increasing temperature affect collision theory

Answer 3

increases the rate of reaction due to more kinetic energy at higher temperatures

Question 4

how does increasing concentration and pressure affect collision theory

Answer 4

increasing concentration/ pressure increases rate of reaction. this is because there is an increase of reactant particles in the same volume therefore larger chance of collisions

Question 5

how does increasing surface area affect collision theory

Answer 5

increases rate of reactions as it exposes more particles to the surface which allows them to have a higher chance of collisions

Question 6

how does the addition of a catalyst affect collision theory

Answer 6

increases rate of reaction

Question 7

the equation for calculating rate of reaction

Answer 7

rate = change in concentration / time

Question 8

what does the boltzmann energy distribution curve

Answer 8

at a given temperature, not all the particles in a sample have the same energy.

Question 9

what effect does the catalyst have on a reaction

Answer 9

changes the activation energy

Question 10

define a homogeneous catalyst

Answer 10

same physical state as the reactants. takes active part in the reaction and are then regenerated as the reaction proceeds

Question 11

define a heterogenous catalyst

Answer 11

different physical state as reactants. provides a surface for reactant particles to absorb to, which holds them in place to react. the product then desorb from the surface

Question 12

how to measure rate of reaction by gas collection method

Answer 12

rate of reaction = volume/time

Question 13

what is the iodine clock used for

Answer 13

to compare reactions under different conditions. it involves setting up reactions with known concentration and time is recorded

Question 14

describe the method of an iodine clock

Answer 14

1. add these to a conical flask
   - KI
   - sodium thiosulfate
   - starch solution
2. add 5cm of hydrogen peroxide to the mixture and start stopwatch
3. stop timer when it turns blue black
4. repeat using different conc of hydrogen peroxide

Question 15

describe the relationship between rate and concentration using I-C reaction

Answer 15

• directly proportional
• concentration increases increases hydrogen peroxide particles number of collisions
• ensure temp is constant