Catalyst Flashcards
rate of reaction
change in concentration divided by the change in time
measure of concentration of one of the species or the amount of product formed
rate of reaction and differentiation
rate of reaction is the equilvant to finding the gradient, so can use differentiation to find the gradient at any point in order to find rate of reaction - especially useful for when we have curved graphs
differentiation
y=ax^b
dy/dx = a(b) x^b-1
instantaneous rate
rate (v) = d[con] /dt
units conc/time
reactants will have negative rate as conc decreasing, products will have +ve rate
stoichiometric equations
when considering the rate with coefficients, need to include in rate equation.
o2 + 2h2 –> 2h2o
rate = -1/1 d[o2] /dt
1/-2 d[h2]/dt = 1/2d[h2o]/dt
instanteous rate vs average rate
instanteous rate is working out the reate via differentiation
average rate is doing change in y / change in x
rate differentiation questions
the components in the equation rates are all equal to eachother, so if you are given the rate of one component, can find the other.
example rate question: if rate of h2 = 5.2x10-4 , what is the rate nh3? n2 +3h2 –> 2nh3
rate = 1/3 x delta H2/Delta T. = 1/2 delta NH3 / delta T
1/3 x 5.2x10-4 /0.5 = delta nh3 /delta T
3.4x10-4
rate laws and rate constant
v = k[A]m [B]n
n + m = orders
K - rate constant
0th order rate
rate = -d[a]/dt = k0[a]^0
1st order rate
d[a]/dt = -k1[a]^1
2nd order rate
d[a]/dt = -k2[A]^2
these rate laws
these are differential equations that describe the rate of change of a reactant of product with time
can use these to solve questions about how the concentration of the reactant or product changes as a function of time
integration
it measures the area under the curve, and can add limits to remove the constant
