3.1.9 Rate Equations

Question 1

how does concentration affect the rate of reaction?

Answer 1

• when conc. increases, more particles in the same volume
• more frequent collisions
• rate of reaction increases

Question 2

how does pressure affect rate of reaction?

Answer 2

• when pressure increases, more gas particles in the same volume
• so the particles are crowded together
• more frequent collisions
• rate of reaction increases

Question 3

how does surface area affect rate of reaction?

Answer 3

• when surface area increases, there are more particles available/exposed to collide with the other reactants
• more frequent collisions
• rate of reaction increases

Question 4

how does temperature affect rate of reaction?

Answer 4

• when temperature increases, particles gain kinetic energy and move faster
• more particles have energy greater than/equal to the activation energy
• more frequent, successful collisions

Question 5

how does a catalyst affect rate of reaction?

Answer 5

• lowers the activation energy by providing an alternative pathway
• more particles have energy greater than the activation energy
• more frequent, successful collisions

Question 6

define ‘rate of reaction’

Answer 6

amount of reactant used OR amount of product formed/time taken

Question 7

what is the Arrhenius Equation?

Answer 7

k = Ae (to the power of -Ea/RT)

Question 8

what do the letters mean in the Arrhenius Equation?

Answer 8

• k = rate constant
• A = pre-exponential frequency factor
• e = natural log constant
• -Ea = activation energy (J/mol)
• R = gas constant
• T = temperature (K)

Question 9

how does the Arrhenius Equation link to the equation of a straight line?

Answer 9

lnk = -Ea/R(T) + lnA
y = mx + c

Question 10

what is the ‘rate determining step’?

Answer 10

the slowest step in the reaction mechanism of a multistep reaction