metals and metal extraction Flashcards
why can metals conduct electricity and non metals dont
because metalic bonding consists of the attraction between positive ions and a sea of delocolised electrons, meaning they are free to move carrying charge. As for non metals, there are no free electrons so they cant conduct electricity
why do metals have high boiling or melting points and non metals have low
As the metallic lattice is held together by strong electrostatic forces of attraction, a lot of energy is needed to separate the metal atoms to melt or boil the metal. Therefore, metals have high melting points and boiling points.
why are metals malleable
When a force is applied to the metal, the layers of the metal ions, with their delocalised electrons, are able to move and slide past the other layers. This prevents the metal structure from breaking; instead, it bends
describe properties of transition metals
high melting points, high densities, form coloured compounds and often act as catalysts as elements and in compounds
what is produced when metals react with dilute acid
salt and hydrogen
describe metallic bonding
the electrostatic attraction between positive ions in a giant metallic lattice and a sea of delocalised electrons
what are alloys
Alloys are a mixture of a metal and another element. They tend to be stronger and harder than pure metals and are therefore much more useful
brass is an alloy and is a mixture of what?
copper and zinc
stainless steal is an alloy and is a mixture of what?
iron and other elements such as, chromium, nickel and carbon
why are alloys stronger than pure metals
because they have different sized atoms in alloys meaning the layers can no longer slide over each other meaning they are also non malleable
what is stainless steal used for
in cutlery because of its hardness and resistence to rusting
what is a redox reaction
a reaction in which both reduction and oxidation happen, involved in the loss and gain of oxygen
what is oxidation
gain of oxygen and loss of electrons
what is reduction
loss of oxygen and gain of electrons
what is an oxidising agent
A substance which oxidises another substance and itself is reduced.
what is a reducing agent
A substance which reduces another substance and itself is oxidised.
what are the oxidiation rules
1- all elements in uncomined state have oxidation=0
2. oxidation number for a monoatomic ion is the same as the charge of the ion eg CL- = -1
3. sum of oxidation numbers in a compound is 0 eg. CuO, cu= 2+ and o= 2-
what happens when you add potassium iodide to a solution and why
it turns brown, Iodide ions changing to iodine is a redox reaction
what happens when you add potassium manganate to solution and why
The potassium manganate(VII) solution turns form purple to pale pink, because manganese is reduced as it gains electrons
explain the trend between reactivity of metals and how they are extracted from their ores
gold and silver are found naturally, copper you must burn with air, less reactive than carbon you can extract by reacting them with carbon, more reactive than carbon use electrolysis
what are the steps to obtain iron from hematite in the blast furnace
- burn carbon/ coke to provide heat and produce co2
-reduce carbon dioxide into carbon monoxide
-then iron (iii) oxide is reduced by carbonmonoxide
-the thermal decomposition of calcium carbonate/ limestone to produce calcium oxide
-the formation of slag
what is the main ore of aluminium and how is it extracted
bauxite, using electrolysis
state the symbol equation present in the blast furnace
1- c + o2 -> co2
2- c + co2 -> 2CO
3- Fe2O3 +3CO -> 2Fe +3CO2
4-CaCO3 -> CaO +CO2
5-Cao + SiO -> CaSiO3
hydrochloric acid + sodium hydroxide →
and write in symbol
sodium chloride + water
HCl + NaOH → NaCl + H2O
combustion of ethanol: equation both
ethanol + oxygen → carbon dioxide + water
C2H5OH + O2 → CO2 + H2O
