rates of reaction

Question 1

Rate of chemical reaction depends on

Answer 1

1. collision frequency of reacting particles. more collisions means faster reaction.
2. Energy transferred during a collision. Particles need to collide with enough energy for collision to be successful.

Question 2

Minimum amount of energy is the particle need to react

Answer 2

Activation energy

Question 3

why do particle need this much energy

Answer 3

to break bonds in reactants and start reaction. greater activation energy, more energy needed to start reaction.

Question 4

temperature factor

Answer 4

1. temperature is increased, particles move faster, more collisions
2. higher temperatures increase energy of collisions. Reactions only happen if particles collide with enough energy
3. higher temperatures means more successful collisions.
4. Increasing temperature, increases rate of reaction

Question 5

concentration factor

Answer 5

1. more concentrated solution means more particles of reactant in same volume, collisions more likely, reaction rate increases
2. In gas, increasing pressure means particles are more crowded. Frequency of collisions increases, the rate of reaction increases

Question 6

surface area factor

Answer 6

1. if reactant is solid, breaking it into smaller pieces, increases its surface area to volume ratio.
2. particles will have more area to work on, frequency of collisions increase
3. Rate of reaction is faster for solids with larger surface area to volume ratio

Question 7

Rate of reaction experiment-how surface area affects rate

Answer 7

1. Measure volume of gas using a gas syringe. Take readings at regular time intervals.
2. plot graph of results. Time on X axis and volume on Y axis
3. Repeat experiment with same volume and concentration of acid and same mass of marble chips, but marble more crunched up
4. Repeat with same mass of powder chalk

Question 8

finer particles of solid experiment

Answer 8

1. finer particles means larger surface area.

2. extra surface area gives a faster reaction and more gas evolved overall

Question 9

Concentration of acid experiment

Answer 9

marble chips experiment
1. Measure effect of concentration
2. repeat with same mass and surface area and same volume of acid but different concentrations of acid.
higher concentration gives a faster reaction with reaction finishing sooner.