Summer assessment 2 Flashcards
what are ions?
charged particles
What is ionic bonding between?
a metal and non-metal
What is ionic bonding?
oppositely charged ions are strongly attracted to one another by electrostatic attrations
What does ionic bonding form?
giant ionic structure
Describe giant ionic structure?
- ions held together by closely packed 3D lattice arrangement
- strong electrostatic attraction
- high melt + boiling point
- not electrical conductors when solid, only when dissolve in water or melt them
Definition of covalent bond?
strong electrostatic attraction between negatively charged shared electrons and the positively changed nuclei of the atoms involved
Describe simple molecular structures?
- very strong covalent bond
- weak intermolecular forces of attraction between molecules
- low melting and boiling point
Describe giant covalent structures?
- strong covalent bond
- high melting and boiling
- dont conduct electricity
- insoluble in water
Describe diamond?
- network of carbon atoms with four covalent bonds
- strong covalent bonds
- high melting point
- hard rigid lattice structure
- doesnt conduct
Describe graphite?
- each carbon forms three covalent bonds
- layers of carbon atoms with weak intermolecular forces which can slide over each other making it slippery and soft
- high melt and boil
- one delocalised electron and can conduct electricity
Describe C60 fullerene?
- hollow sphere with 60 carbon atoms
- intermolecular foces which can slide over each other - soft
- one delcocalised but cant move molecules so poor conductor
What is the name of group 7?
halogens
What happens as atomic number increases for halogens?
elements have darker colour and a higher boiling point
Describe chlorine?
poisonous green gas
Describe bromine?
red-brown liquid gives off orange vapour at room temperature
Describe iodine?
dark grey crystalline solid which gives off purple vapour when heated
When do salts form?
when acids react with bases in a neutralisation reaction
acid + base = ?
salt + water
acid + metal oxide =?
salt + water
acid + metal hydroxide =?
salt + water
acid + ammonia =?
ammonium salt
acid + metal carbonate=?
salt + water + carbon dioxide
Test for chlorine?
bleaches damp blue litmus paper, turning it white
test for oxygen?
relights a glowing splint
test for CO2
turns limewater cloudy
test for hydrogen
squeaky pop with lit splint
test for ammonia?
turns damp red litmus paper blue
test for water?
copper sulfate crystals become blue
What two ways can you find formula using experiments?
combustion reaction and reduction reaction
What is the combustion reaction for finding the empirical formula?
- heat crucible till red hot ( cleans it)
- cool and then weigh
- add magnesium ribbon, reweigh
- heat with magnesium
- heat for 10 mins or until magnesium turned white
- cool and reweigh
What is the reduction reaction for finding empirical formula?
- weigh rubber bung and test tube with small hole in end
- add some copper oxide into middle of tube
- reinsert bung and weigh
- expel air by turning on gas
- light bunsen and heat for 10 mins or change from black to brown pink
- cool and weigh
What does soluble mean?
dissolve in water
What does an insoluble salt form?
percipitate
Which substances are soluble?
sodium potassium ammonium nitrates chlorides ( not silver or lead) sulfates ( not lead barium and calcium
Which substances are insoluble?
carbonates ( not sodium potassium and ammonium)
hydroxides ( not sodium potassium and calcium)
how do to make a soluble salt?
by reacting an acid that contains one of the ions you want and an insolube base with the other ion
Explain process of making soluble salts?
- heat acid in water bath
- add base to acid until in excess
- filter off excess
- heat gently using bunsen to slowly evaporate water
- leave to dry and crystalise then filter solid salt
What are alkanes?
saturated hydrocarbons
What are hydrocarbons?
chains of carbon and hydrogen atoms
alkanes general formula?
CnH2n+2
name the first five alkanes?
methane ethane propane butane pentane
WHat do alkanes burn in?
combustion reactions
What does complete combustion of alkane make?
carbon dioxide + water
What can alkanes react with? to form?
halogens to make haloalkanes
what is needed for the substitution reaction?
UV light
Methane + bromine =?
bromomethane + hydrogen bromide