Reaction Rates

Question 1

Heat of Reaction

Answer 1

the energy absorbed or released in a chemical equation

Question 2

Exothermic Reaction

Answer 2

reactions that release energy

Question 3

Endothermic Reaction

Answer 3

reactions that absorb energy

Question 4

Activation Energy

Answer 4

the minimum energy needed for a reaction to take place

Question 5

Reaction Rate

Answer 5

the change in concentration of reactants or products per unit time

Question 6

Collision Theory

Answer 6

a model that explains reaction rate as the result of particles colliding with a certain minimum energy

Question 7

Positive Catalyst

Answer 7

a substance that increases the rate of a chemical reaction without itself undergoing a permanent change

Question 8

Potential Energy curve

Answer 8

Look at graph on page 1 of notes and learn the 9 labels

Question 9

What is an Effective Collision

Answer 9

• reacting particles are correctly aligned when they collide
• reacting particles must have sufficient kinetic energy to break existing bonds

Question 10

Factors effecting Reaction Rate [5]

Answer 10

1. Nature of the substance
2. Surface area of the substance
   (greater SA means faster rate)
3. Concentration of the substance
   (Increase in [ ] means a faster rate)
   (Increase in pressure means an increase in [ ])
4. Temperature
   (higher temp means faster rate)
5. Use of a catalyst

Question 11

Learn the EXPLANATIONS for each factor of reaction rate

Answer 11

page 2 of notes

Question 12

Maxwell-Boltzmann Distribution Curve

Answer 12

• shows the number of particles able to go effective collisions
• increase in temperature causes the number of particles able to undergo effective collisions to increase
• redraw the curve
• curves must have same area under the line
• area under line = number of particles
• catalyst just pushes the minimum energy line closer to the origin (no redraw of curve!!)

Question 13

Product vs Time Graphs

Answer 13

• reaction will always end at a certain point
  (only so much can be produced)
• reaction rate starts out fast and decreases over the course of the reaction

Question 14

Reactant vs Time Graphs

Answer 14

• opposite shape to product graph
• graph can intercept x axis (meaning reactant is used up) or flatline above it (meaning that the other reactant is the limiting reactant)
• reaction rate starts out fast and decreases over the course of the reaction