Phil Denton Flashcards
Why is the rate of change of diamond to graphite negligible?
The activation energy is high - nothing to do with delta G as that determines the equilibrium position
What is the units of reaction rate?
Moles or amount per unit time e.g. mol dm-3 s-1
Which of the following are not units for reaction rate: mol dm-3 s-1 M s-1 mol -1 dm3 s-1 uM min-1 g min-1
mol -1 dm3 s-1
What are the units of k if V=k[A][B]2?
mol-2 dm6 s-1
What is the activation energy of a reaction?
Minimum amount of energy need for a reaction to occur
What is molecularity?
Number of reactant particles involved in a reaction
A bimolecular reaction is?
An elementary step involving 2 reactant molecules
What do catalysts do to the activation energy?
It lowers the activation energy by finding an alternate route to the products
What is the rate law?
A mathematical function that tells you how fast a chemical reaction is going based on the concentration of the reactants
If a first order reaction was plotted on a graph and the gradient = -0.17s-1 and the intersect = -2.3. Find out the value of k/s-1 and [A]0/M?
- 17 - as you can never get a negative number
0. 1 - exp (-2.3)
What is the half life of a drug substance?
The time taken for the concentration of the reactants to halve
In a reaction the initial rate x8 when the concentration of A x4. The order in A is…?
Three halves - 1.5
Calculate the half-lives/hr of these drugs. Degradation rate constant = 6.30x10-2 hr-1 AND 4.62x10-3 hr-1
11.0 - (ln 2) / 6.30x10-2
150 - (ln 2) / 4.62x10-3
What effect does temperature have on ‘k’ ?
As temperature increase so to does k - at higher temperatures the number of particles that have energy greater than the activation energy has increased
What 3 factors does the collision theory rely on?
Rate of collision - speed
Reactant orientation - steric effect (states how many reactions will occur due to right orientation)
Energy required - activation energy
