week 5 defs

Question 1

acid

Answer 1

a proton donor

Question 2

base

Answer 2

proton acceptor

Question 3

conjugate acid-base pairs

Answer 3

a pair of two species that transform into each other by gain or loss of a proton

Question 4

strong acid

Answer 4

a proton donor that completely dissociates in a solution

Question 5

weak acid

Answer 5

a proton donor that partially dissociates in solution

Question 6

acid dissociation constant

Answer 6

shows the extent of acid dissociation and is defined as:
Ka= [H+][A-] for
[HA]
for acid HA: HA(aq) -> H+(aq) + A-(aq)

Question 7

pH

Answer 7

pH + -log[H+] (so, [H+]=10-pH

Question 8

ionic product of water Kw

Answer 8

Kw = [H+][OH-]
(at 25’C, Kw = 1.00 x 10-14 mol2dm-6)

Question 9

buffer solution

Answer 9

a system that minimises pH changes of addition of small amounts of an acid or a base

Question 10

rate of raction

Answer 10

the change in concentration of a reactant or product per unit time

Question 11

Order m

Answer 11

the order with respect to a reactant is the power to which the concentration of the reactant is raised in the rate equation

Question 12

rate constant, k

Answer 12

the constant that links the rate of reaction with the concentrations of the reactants raised to the powers to the powers of their orders in the rate equation

Question 13

rate equation

Answer 13

for A + B -> products
rate = k[A}m [B]n

Question 14

half-life

Answer 14

the time taken for the concentration of the reactant to reduce by half

Question 15

rate determining step

Answer 15

the slowest step in the reaction mechanism of a multi-step reaction