C3 - Chemicals of the Natural Environment Flashcards
what can the reactivity series tell you about metals?
the higher up the reactivity series a metal is, the more easily it looses electrons and forms positive ions
what type of bonding do metals use?
metallic bonding
describe the structure and bonding of metals? (3)
giant structure
give up their outer shell electrons, which becomes delocalised
metals ions are arranged in a regular lattice structure
why are metals good at conducting electricity and heat?
the delocalised electrons are free to move so can carry electrical charge and thermal energy through the material, hence good conductors
acid + metal →
acid + metal → salt + hydrogen
metal + water →
metal + water → metal hydroxide + hydrogen
what are ores?
are rocks that contain enough metal to make it economically worthwhile extracting the metal from it
how can you extract using carbon?
metals below carbon in a reactivity series are extracted using displacement by carbon
what is phytoextraction?
growing plants in soil that contain metal compounds
the plants get burned in a furnace
the ash contains metal compounds from which the metal can be extracted by electrolysis or displacement
what is bioleaching?
uses bacteria to convert insoluble metal compounds in the ore into more soluble compounds
what are the advantages of phytoextraction and bioleaching?
less damaging to the environment than traditional methods and take less energy
what is oxidation?
loss of electrons
what is reduction?
a gain of electrons
what is electrolysis?
refers to breaking something apart using electricity
what is an electrolyte?
a liquid or solution that conducts electricity
what is an electrode?
a solid that conducts electricity and is submerged in the electrolyte
what happens to positive ions during electrolysis?
attracted to cathode
gain electrons
//reduced
what happens to negative ions during electrolysis?
they move towards the anode
lose electrons
//oxidised
why can molten ionic compounds be electrolysed?
the ions can move freely when the ionic compound is molten and thus they can conduct electricity
in the electrolysis of a solution, which 2 ions are present from the water molecules themeselves?
H+ ions and OH- ions
in the electrolysis of aqueous solutions, what is the rule determining which ion will be oxidised at the anode?
it will always be OH-, unless there is a halide present
in the electrolysis of aqueous solutions, what is the rule for determining which ion will be reduced at the cathode?
always the ion which is the least reactive element
why is aqueous electrolysis generally cheaper than molten electrolysis?
the substance is just dissolved in water, no energy is required to melt it
describe a covalent bond?
electrostatic attraction between a shared pair of electrons and the nuclei of the 2 bonded atoms
is is formed when 2 atoms share electrons to gain a full outer shell of electrons
