3.4 chemistry Flashcards
pH < 7
acidic
pH = 7
neutral
pH > 7
alkaline
methyl orange: acidic, neutral and alkaline colours:
red, yellow and yellow
phenolphthalein: acidic, neutral and alkaline colours:
colourless, colourless and pink
red litmus paper: acidic, neutral and alkaline colours:
red, red and blue
blue litmus paper: acidic, neutral and alkaline colours:
red, blue and blue
what is an indicator
it is a substance that changes colour to tell you about the pH of a solutuon
the universal indicator is special because
the range of colours tells you the approximate pH
effervescence is
the escape of gas from an aqueous solution (salt CARBONATE)
nitrogen % in air
N2 = 78%
oxygen % in air
O2 = 21%
argon % in air
Ar = 0.96%
carbon dioxide % in air
CO2 = 0.04%
what is element combustion
it’s when an element reacts with oxygen to produce an oxide
sulphur + oxygen -> sulphur dioxide
S(s) + O2(g) -> SO2(g) v
sulphur dioxide observation is
a blue flame
metal ion of iron(II)
Fe2+ ^
metal ion of silver
Ag+ ^
metal ion of iron(III)
Fe3+ ^
metal ion of zinc
Zn2+ ^
metal ion of copper
Cu2+ ^
metal ion of lead
Pb2+ ^
acid definition
H+ donor ^
base definition
H+ acceptor ^
alkali definition
OH- donor ^
sodium hydroxide + sulphuric acid ->
sodium sulphate + water
what is titration
it is a method for making a soluble salt from a soluble base and an acid
titration method is used to make salts that contain which ions
sodium Na+
potassium K+
ammonium NH4+
why do you use titration method when making salts that contain potassium, sodium or ammonium ions?
because their bases are all soluble so you wouldn’t be able to filter out the excess if you use the insoluble base method
what are 3 usual acids
hydrochloric acid • HCl
sulphuric acid • H2SO4
nitric acid • HNO3
what are 3 usual alkalis
sodium hydroxide • NaOH
potassium hydroxide • KOH
ammonium hydroxide • NH4OH
insoluble base method
- HEAT sulphuric acid in a beaker
- whilst stirring with a glass rod ADD copper oxide until NO MORE dissolves
- let the mixture COOL before FILTERING to remove the excess base (insoluble)
- let the salt solution COOL DOWN
- HEAT the salt solution until some crystals start to form
- allow the solution to COOL in an evaporating basin
- FILTER out the crystals
- DRY the crystals by dabbing them with filter paper
crystallisation method
- HEAT the salt solution until some crystals start to form
- allow the solution to COOL in an evaporating basin
- FILTER out the crystals
- DRY the crystals by dabbing them with filter paper
short insoluble base words
HEAT
ADD
NO MORE
COOL
FILTER
COOL DOWN
HEAT
COOL
FILTER
DRY
short filtering words
HEAT
COOL
FILTER
DRY
acid + base (oxide)
insoluble base method
acid + alkali (hydroxide)
titration
titration method
- place a known volume of *acid (hydrochloric acid)
- add a few drops of indicator
- using a burette start adding *alkali solution (potassium hydroxide) until the colour starts to change
- stop adding the alkali and measure how much has been added to change the colour
- repeat the titration but without using the indicator and using a burette to add exactly the right volume to the acid for neutralisation
crystallisation!!
ammonium ion
NH4+
hydroxide ion
OH-
nitrate ion
NO3-
sulphate ion
SO42-
carbonate ion
CO32-
hydrocarbonte ion
HCO3-
nitric acid
Acid formula: HNO3
Ion formula: NO3-
Ion name: Nitrate
sulphuric acid
Acid formula: H2SO4
Ion formula: SO42-
Ion name: Sulphate
phosphoric acid
Acid formula: H3PO4
Ion formula: PO43-
Ion name: Phosphate
carbonic acid
Acid formula: H2CO3
Ion formula: CO32-
Ion name: Carbonate
knowing bases
have O or CO
(oxides or carbonates)
knowing salts
SO4, CL, NO3, PO4, ethanoates + citrates
(common acids)
knowing alkalis
OH
(hydroxide)
knowing acids
H2SO4 (sulphuric)
HCL (hydrochloric)
HNO3 (nitric)
H3PO4 (phosphoric)
CH3COOOH (ethanoic)
what is the formula of strontium chloride
SrCl2
what is the formula for potassium nitride
K3N
what is the formula for copper (II) oxide
CuO
what is the formula for silver (I) chloride
AgCl
what’s the formula for chromium (III) oxide
Cr2O3
list the properties of ionic compounds and list the reasons for those properties
• they have high m + b points
• strong electrostatic forces
• a giant lattice structure
• forces act in all directions
• require a lot of energy to break
________________________________________
• they are soluble in polar substances
(like water)
• poor conductors when solid
(ions in fixed position)
• conduct electricity in liquid
(ions are free to move)
% of oxygen in the atmosphere
burning phosphorus in an evaporating basin in a bell jar which is immersed in a trough of water
what are the following four acids:
• H2So4
• HNO3
• HCl
• H3PO4
sulphuric acid
nitric acid
hydrochloric acid
phosphoric acid