metals and metal extraction

Question 1

why can metals conduct electricity and non metals dont

Answer 1

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

Question 2

why do metals have high boiling or melting points and non metals have low

Answer 2

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.

Question 3

why are metals malleable

Answer 3

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

Question 4

describe properties of transition metals

Answer 4

high melting points, high densities, form coloured compounds and often act as catalysts as elements and in compounds

Question 5

what is produced when metals react with dilute acid

Answer 5

salt and hydrogen

Question 6

describe metallic bonding

Answer 6

the electrostatic attraction between positive ions in a giant metallic lattice and a sea of delocalised electrons

Question 7

what are alloys

Answer 7

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

Question 8

brass is an alloy and is a mixture of what?

Answer 8

copper and zinc

Question 9

stainless steal is an alloy and is a mixture of what?

Answer 9

iron and other elements such as, chromium, nickel and carbon

Question 10

why are alloys stronger than pure metals

Answer 10

because they have different sized atoms in alloys meaning the layers can no longer slide over each other meaning they are also non malleable

Question 11

what is stainless steal used for

Answer 11

in cutlery because of its hardness and resistence to rusting

Question 12

what is a redox reaction

Answer 12

a reaction in which both reduction and oxidation happen, involved in the loss and gain of oxygen

Question 13

what is oxidation

Answer 13

gain of oxygen and loss of electrons

Question 14

what is reduction

Answer 14

loss of oxygen and gain of electrons

Question 15

what is an oxidising agent

Answer 15

A substance which oxidises another substance and itself is reduced.

Question 16

what is a reducing agent

Answer 16

A substance which reduces another substance and itself is oxidised.

Question 17

what are the oxidiation rules

Answer 17

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-

Question 18

what happens when you add potassium iodide to a solution and why

Answer 18

it turns brown, Iodide ions changing to iodine is a redox reaction

Question 19

what happens when you add potassium manganate to solution and why

Answer 19

The potassium manganate(VII) solution turns form purple to pale pink, because manganese is reduced as it gains electrons

Question 20

explain the trend between reactivity of metals and how they are extracted from their ores

Answer 20

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

Question 21

what are the steps to obtain iron from hematite in the blast furnace

Answer 21

• 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

Question 22

what is the main ore of aluminium and how is it extracted

Answer 22

bauxite, using electrolysis

Question 23

state the symbol equation present in the blast furnace

Answer 23

1- c + o2 -> co2
2- c + co2 -> 2CO
3- Fe2O3 +3CO -> 2Fe +3CO2
4-CaCO3 -> CaO +CO2
5-Cao + SiO -> CaSiO3

Question 24

hydrochloric acid + sodium hydroxide →
and write in symbol

Answer 24

sodium chloride + water
HCl + NaOH → NaCl + H2O

Question 25

combustion of ethanol: equation both

Answer 25

ethanol + oxygen → carbon dioxide + water
C2H5OH + O2 → CO2 + H2O