Chapter 11 - Chemical Kinetics Flashcards
What is the rate for equation aA—->bB
Rate = —(1/a)•(Δ[A]/Δt) = (1/b)•(Δ[B]/Δt)
What is the rate law?
- Only concerns REACTANTS
- Rate = k[A]^x[B]^y
- xth order of A
- yth order of B
- (x+y)th order of reaction
What is equation for reaction rate?
- Δ[A]/Δt
- Δ[A] is the change in concentration of reactant/product A
- reactants are (–)
- products are (+)
How to determine rate law exponents from experimental data?
*Take ratio of rates and equate them to ratio of rate law equations
What is the equation for first-order reaction? Half-life?
- ln[A] = ln[A]i – kt
* ln(2)/k
How do you determine k graphically?
It’s the negative slope of line.
What is the equation for second order reaction? Half-life?
- 1/[A] = 1/[A]i + kt
* t = 1/(k•[A]i)
What is the ‘k’ value units in 1st, 2nd, and 0 order reactions?
*1st - s^-1
*2nd - M^-1•s^-1
0 - M/s
Equation for Zero Order reaction? Half life?
- [A] = [A]i – kt
* t = [A]i/(2k)
What is the Arrhenius Equation?
k = Ae^(Ea/RT)
R 8.314
What is better form of Arrhenius equation when comparing two rates or temps?
ln(k2/k1) = – (Ea/R)((1/T2)–(1/T1))
What’re intermediates?
Molecules that’re canceled out in elementary steps.
How to tell the molecularity of a reaction? (In elementary steps)
- Uni- one reactant k[A]
- Bi - two k[A][B], k[A]^2
- Term- 3 or more
The rate determining step is the slowest into leading product formation.
S
What does a catalyst do to a chemical reaction?
Lowers Activation energy and heightens k (rate)
