acids

Question 1

acid + metal

Answer 1

= salt + hydrogen

Question 2

acid + metal oxide

Answer 2

=salt + water

Question 3

acid + metal hydroxide

Answer 3

=salt + water

Question 4

acid + metal carbonate

Answer 4

= salt + co2 + water

Question 5

ammonia + hydrochloric acid =

Answer 5

NH4CL(aq)

Question 6

type of acid used and salt formed

Answer 6

hydrochloric - chloride (cl-)
sulfuric - sulfate (SO42-)
nitric - nitrate (NO3-)
phosphoric - phosphate (PO43-)
ethanoic - ethanoate (CH3COO-)

Question 7

definition of an acid

Answer 7

proton donor

Question 8

monoprotic / diprotic

Answer 8

monoprotic acids release 1 H+
diprotic acids release 2 H+

Question 9

definition of a base

Answer 9

a base is a proton acceptor
will accept and bind to H+

Question 10

water

Answer 10

water can act as a base or an acid so amphoteric

Question 11

strong acids

Answer 11

fully dissociates
equilibrium lies entirely to the right hand side
so if original conc of strong acid is x when it fully dissociates the conc of H+ will now be x

Question 11

equation of PH

Answer 11

PH = -Log10[H+]

Question 11

weak acids

Answer 11

partially dissociate
position of equilibrium is way over to the left hand side - cant work out concentration H+

Question 12

examples of strong acids

Answer 12

HCl
H2SO4
HNO3
H3PO4

Question 13

Ka

Answer 13

used to figure out amount of H+ ions that have partially dissociated
higher Ka - more dissociated

Question 14

ka expression example
eg HCOOH(aq) <-> HCOO-(aq) +H+(aq)

Answer 14

Ka = [H+] [HCOO-] / [HCOOH]
[H+] = [HCOO-]
Ka = [H+] ^2 / [HCOOH]
rearrange to find [H+]

Question 15

PKa=

Answer 15

pKa = -Log10Ka

Question 16

Kw

Answer 16

Kw ionic product of water
alters with temp
Kw = [H+] [OH-] —– Kw = [H+]^2
grouped together as Kc and [H20] are constants

Question 17

pure water is neutral

Answer 17

[H+] = [OH-]

Question 18

Kw value at 298K

Answer 18

1x10-14

Question 19

water dissociation
Temp rise

Answer 19

forward reaction is endothermic
at temperatures of 298K the equilibrium shifts to the right to oppose the temperature rise
this means that [H+] increase

Question 20

strong bases

Answer 20

fully dissociate to release OH- ions
position of equilibrium lies entirely to the right hand side
USE KW
Kw=[H+][OH-]
[OH-] = conc of base as fully dissociates

Question 21

method for PH titrations

Answer 21

1-measure the PH of the acid solution and record
2-add 1cm3 of the base solution
3-stir the mixture
4-measure the ph and record
5-repeat the process until the base is in excess
6-add base in smaller increments near the end point

Question 22

why should you calibrate the ph meter

Answer 22

important to calibrate as after storage it may not give an accurate reading
to calibrate it you place the ph meter in a solution of known ph and then adjust the meter accordingly

Question 23

equivalence point

Answer 23

is when exactly enough acid has been added to neutralise the base
mid point on the vertical section of the graph