Rate of Reaction

Question 1

define rate of reaction

Answer 1

how fast or how slow a reaction takes

Question 2

what are some ways to measure speed of reactions?

Answer 2

• time taken for a reaction to be completed
• volume of gas evolved
• change in mass of the reaction mixture

Question 3

what can be changes can be measured when looking at time?

Answer 3

• change in volume of gas evolved
• change in mass of reaction mixture as the reaction proceeds
• change in pressure of gas formed

Question 4

how long does it take for half the mass of the substance to react?

Answer 4

take half of the volume and find the time

Question 5

explain the changes in the graph

Answer 5

initial -> reactants are available in highest concentration
overtime -> concentration decreases, less effective collisions
final -> one reactant is used up, reactions come to a stop

Question 6

why does the mass of the flask and it’s contents decrease overtime?

Answer 6

the gas is given off to the surroundings

Question 7

why is cotton wool placed at the mouth of the conical flask?

Answer 7

to prevent loss of mass of the solution due to acid spray

Question 8

what is required for a reaction to occur between two particles?

Answer 8

• reacting particles must collide with each other
• must collide with a certain minimum amount of energy also known as activation energy
• so that collisions between reacting particles result in formation of product particles
• collisions are also known as effective collisions

Question 9

what are the factors which affect the speed of reaction?

Answer 9

• size of solid reactant
• concentration of reactant in solution
• temperature
• pressure of gaseous reactants

Question 10

how does the size of the solid reactant affect the speed of reaction?

Answer 10

• smaller particle size, larger total surface area exposed to collisions
• higher frequency of effective collisions, higher speed of reaction

Question 11

how does the concentration of the reactant in solution affect the speed of reaction?

Answer 11

• higher concentration of reactant, higher number of particles per unit volume
• higher frequency of effective collisions, higher speed of reaction

Question 12

how does temperature affect the speed of reaction?

Answer 12

• at higher temperature, reactant particles have more kinetic energy and move faster
• higher frequency of effective collisions, higher speed of reaction

Question 13

how does the pressure of gaseous reactants affect the speed of reaction?

Answer 13

• higher pressure of gaseous reactants, the smaller the volume
• higher number of particles per unit volume, higher frequency of effective collisions, higher speed of reaction