Acids and Redox Flashcards
1
Q
Define polyprotic
A
- acids that donate more than one proton
E.g 1 mole of H2SO4 will produce 2 moles of H+
2
Q
what pH are salts
A
pH neutral
3
Q
acid + base
A
salt + water
4
Q
Describe ammonia reaction with acids
A
- ammonia reacts with acids to make ammonium salts
- no water is formed.
2NH3 + H2SO4 = (NH4)2SO4
5
Q
Metal + acid
A
salt + hydrogen
6
Q
metal oxide + acid
A
salt + water
7
Q
metal hydroxide + acid
A
salt + water
8
Q
metal carbonate
A
salt + water + carbon dioxide
9
Q
colour changes of indicators
A
- phenolphthalein : colourless in acid and pink in alkali
- methyl orange : red in acid and yellow in alkali
10
Q
How to make a standard solution
A
- SS is when you have a known conc
- weigh the solid in a boat using a balance
- transfer solid from boat to beaker
- wash any solid left with deionised water
- ensures all of solid is transferred
- dissolve solid using DW
- stir to ensure solid is fully dissolved
- transfer solution to a volumetric flask using a funnel
- rinse the beaker and rod into the flask so all of it is transferred
- fill volumetric flask using deionised water to the graduation line using a pipette.
- invert the flask and mix.
11
Q
Explain what type of reaction calcium + oxygen is and why?
A
Ca + 0.5 O2 = CaO
- Redox reaction
- Ca = Ca2+ + 2e- (Ca is oxidised as it loses electrons)
- O2 + 2e- = O2- (oxygen is reduced as it gains electrons)
12
Q
What are reducing agents
A
- RA lose electrons
- they are the species being oxidised
13
Q
What are oxidising agents
A
- OA gain electrons
- they are the species being reduced.
14
Q
Ox number of uncombined elements?
A
always 0
- Cl2, Fe
15
Q
Ox number of ions
A
Ox number is the same as the charge on the ion
Cl- = -1
Ca2+ = +2
