chemistry metals

Question 1

state of metals

Answer 1

Nearly all metals are solids

Question 2

Melting point of metals

Answer 2

Most metals have a reasonably high meting point (strong attractions holding
the solid together.

Question 3

colour of metals

Answer 3

most are a silvery-grey colour

Question 4

Lustre of metals

Answer 4

metals are shiny when freshly cut

Question 5

Strength of metals

Answer 5

Most metals have a high tensile strength

Question 6

malleability of metals

Answer 6

all metals can be worked and shaped.

Question 7

Ductility of metals

Answer 7

all metals can be stretched out into wires

Question 8

Conductivity of metals

Answer 8

All metals are good conductors of both heat and electricity

Question 9

describe transition elements

Answer 9

They have high densities, high melting points and form coloured compounds, and which, as elements and compounds,
often act as catalysts.

Question 10

Properties of alloys

Answer 10

hardness, toughness, corrosion resistance, magnetizability, and ductility

Question 11

why alloys are used instead of pure metals

Answer 11

Pure metals are rather soft, ductile and corrosive. Adding other substances can make the pure metal stronger and/or corrosion resistant. This is the advantage of alloys as opposed to pure metals.

Question 12

do transition elements have variable oxidation states.

Answer 12

yes

Question 13

what do more reactive metals have a greater tendency to do

Answer 13

More reactive metals have a greater tendency to lose electrons and form positive ions.

Question 14

what do less reactive metals have a greater tendency to do

Answer 14

The least reactive metals have the greatest tendency to form atoms and therefore their
compounds are less stable.

Question 15

Mild steel elements and properties

Answer 15

Carbon and iron

Easy to bend and pull into wires

Question 16

tool steel elements and properties

Answer 16

Tungsten, carbon and iron

Hard, can be heated to high temperatures

Question 17

Stainless steel elements and properties

Answer 17

Chromium, carbon and iron Hard, does not rust easily

Question 18

solid pure metal structure

Answer 18

The atoms are arranged in layers. When a force is applied, the layers may slide over each other. The greater the force needed, the harder and stronger the metal.

Question 19

Why is alloy stronger than pure metal

Answer 19

In a pure metal, the force needed to make the layers slide over each other is small. In an alloy, there are atoms of different sizes. The smaller or bigger atoms distort the
layers of atoms in the pure metal. This means that a greater force is required for the layers to slide over each
other. The alloy is harder and stronger than the pure metal.

Question 20

properties and uses of aluminium

Answer 20

property: Doesn't react with water
Light, strong, conducts well
Light, strong, cheap
Light, conducts heat well
Light, strong, unreactive

Uses: Containers and packaging
Long distance wiring
Transport vehicles
Car engines
Buildings (windows etc.)

Question 21

Property and uses of zinc

Answer 21

property: Reactive
More reactive than iron

Uses: Dry cells
Galvanising

Question 22

Property and uses of Iron

Answer 22

Properties: Similar expansivity
Strong, cheap
Strong and abundant

Uses: Reinforcing concrete
Nails
Ship building

Question 23

property and uses of solder

Answer 23

A mixture of 70% Sn and 30 % Pb. Used for joining wires and pipes. Made to give
a low melting point.

Question 24

Properties and uses of brass

Answer 24

Copper 60-95 % zinc 5-40 %. Used for heat exchangers, screws, zips, jewellery,
hose & pipe fittings, taps, radiator valves. A corrosion resistant alloy.

Question 25

properties and uses of bronze

Answer 25

Originally meant Cu 90 % Sn 10 % but the term is now much more widely used to include alloys of aluminium & copper called aluminium bronzes and phosphor bronzes which are Cu/Sn/P. They are strong and corrosion resistant. Uses include anything nautical, ornaments, bells and bearings.

Question 26

Properties and uses of steel

Answer 26

Mixtures of Fe & C but varying amounts are used and other elements are added to give certain properties.

Question 27

what is the order of reactivity used for

Answer 27

The order of reactivity is used to predict what will happen when a metal is placed in a solution of a salt of another metal. if something that is more reactive is added to something less reactive, it will displace ions of that less reactive thing. But not the other way round

Question 28

General rule of reactive series

Answer 28

Any metal will displace another metal lower on the reactivity series from a solution of its ions. (Can only be applied to mg and anything less reactive than mg

Question 29

What is an ore

Answer 29

An ore is any naturally-occurring source of a metal that you can economically extract the metal from

Question 30

What is the most common ore

Answer 30

Aluminium

Question 31

name a rare ore found in high grade ores

Answer 31

Copper

Question 32

Three examples of oxide ores

Answer 32

Bauxite (Al2O3), Haematite (Fe2O3) or Rutile (TiO2)

Question 33

Two examples of Sulphide ores

Answer 33

pyrite (FeS2) or Chalcopyrite (CuFeS2)

Question 34

what does concentrating the ore mean

Answer 34

This simply means getting rid of as much of the unwanted rocky material as possible before the ore is converted into the metal. In some cases this is done chemically

Question 35

Froth flotation (method of concentrating ore)

Answer 35

The ore is first crushed and then treated with something which will bind to the particles of the metal compound that you want and make those particles hydrophobic.

Question 36

what does hydrophobic mean

Answer 36

"Hydrophobic" literally means "water | fearing".

Question 37

What is used for concentrating copper ores

Answer 37

pine oil is often used. The pine oil binds to the copper | compounds, but not to the unwanted rocky material

Question 38

How is copper ore concentrated after pine oil is added

Answer 38

The treated ore is then put in a large bath of water containing a foaming agent (a soap or detergent of some kind), and air is blown through the mixture to make a lot of bubbles. Because they are water-repellent, the coated particles of the metal compound tend to be picked up by the air bubbles, float to the top of the bath, and are allowed to flow out over the sides. The rest of the rocky material stays in the bath.

Question 39

why is metal oxides ore being reduced

Answer 39

the ore is being reduced because oxygen is being | removed.

Question 40

why is metal sulphides ore being reduced

Answer 40

To a reasonable approximation, you can think of these ores as containing positive metal ions. To convert them to the metal, you need to add electrons - reduction.

Question 41

economic factors of reduction

Answer 41

the cost of the reducing agent; energy costs; the desired purity of the metal.

Question 42

Carbon reduction

Answer 42

Carbon (as coke or charcoal) is cheap. It not only acts as a reducing agent, but it also acts as the fuel to provide heat for the process

Question 43

Explain reduction by electrolysis

Answer 43

This is a common extraction process for the more reactive metals - for example, for aluminium and metals above it in the electrochemical series. You may also come across it in other cases such as one method of extracting copper and in the purification of copper. During electrolysis, electrons are being added directly to the metal ions at the cathode (the negative electrode). a downside is the cost of electricity

Question 44

The heat source of the blast furnace

Answer 44

``` The air blown into the bottom of the furnace is heated using the hot waste gases from the top. Heat energy is valuable, and it is important not to waste any. The coke (essentially impure carbon) burns in the blast of hot air to form carbon dioxide - a strongly exothermic reaction. This reaction is the main source of heat in the furnace. ```

Question 45

the function of limestone

Answer 45

Iron ore isn't pure iron oxide - it also contains an assortment of rocky material. This wouldn't melt at the temperature of the furnace, and would eventually clog it up. The limestone is added to convert this into slag which melts and runs to the bottom. The heat of the furnace decomposes the limestone to give calcium oxide

Question 46

Cast iron

Answer 46

The molten iron from the bottom of the furnace can be used as cast iron. Cast iron is very runny when it is molten and doesn't shrink much when it solidifies. It is therefore ideal for making castings - hence its name. However, it is very impure, containing about 4% of carbon. This carbon makes it very hard, but also very brittle. If you hit it hard, it tends to shatter rather than bend or dent.

Question 47

what is cast iron used for

Answer 47

Cast iron is used for things like manhole covers, cast iron pipes, valves and pump bodies in the water industry, guttering and drainpipes, cylinder blocks in car engines, Aga-type cookers, and very expensive and very heavy cookware.

Question 48

How is steel made

Answer 48

Most of the molten iron from a Blast Furnace is used to make one of a number of types of steel. There isn't just one substance called steel - they are a family of alloys of iron with carbon or various metals. Impurities in the iron from the Blast Furnace include carbon, sulphur, phosphorus and silicon. These have to be removed.

Question 49

how is sulphur removed from steel

Answer 49

Sulphur has to be removed first in a separate process. Magnesium powder is blown through the molten iron and the sulphur reacts with it to form magnesium sulphide. This forms a slag on top of the iron and can be removed. The still impure molten iron is mixed with scrap iron (from recycling) and oxygen is blown on to the mixture. The oxygen reacts with the remaining impurities to form various oxides. The carbon forms carbon monoxide. Since this is a gas it removes itself from the iron! This carbon monoxide can be cleaned and used as a fuel gas.

Question 50

How is phosphorus and silicon removed from steel

Answer 50

Elements like phosphorus and silicon react with the oxygen to form acidic oxides. These are removed using quicklime (calcium oxide) which is added to the furnace during the oxygen blow. They react to form compounds such as calcium silicate or calcium phosphate which form a slag on top of the iron.

Question 51

what is galvanising

Answer 51

Galvanising is a method of rust prevention. The iron or steel object is coated in a thin layer of zinc. This stops oxygen and water reaching the metal underneath - but the zinc also acts as a sacrificial metal. Zinc is more reactive than iron, so it oxidises in preference to the iron object.

Question 52

Reactivity series

Answer 52

``` most reactive: Potassium Sodium Calcium Magnesium Aluminium Carbon Zinc Iron Lead Hydrogen Least reactive: Copper ```

Question 53

Should you use the word cloudy

Answer 53

no, use scientific words