Products from Rocks C1a

Limestone is mainly made from calcium carbonate CaCO

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Limestone used to make glass HEAT AT HIGH TEMPERATURE Powdered Limestone Sand Sodium carbonate

Limestone used to make cement HEAT Powdered Limestone Powdered clay

Limestone used to make Concrete MIX Cement powder Water Sand Crushed rock

Thermal decomposition – breaking down a chemical by heating

Thermal decomposition of limestone Heat Calcium Carbonate Calcium oxide + Carbon dioxide CaCO 3 CaO + CO 2

Limestone decomposes to form calcium oxide (quicklime) and carbon dioxide

General equation for the thermal decomposition of a metal carbonate Metal carbonate  Metal oxide + Carbon dioxide

Quicklime + water  Slaked lime Calcium oxide + water  Calcium hydroxide CaO + H 2 0  Ca(OH) 2

Dissolve slaked lime (calcium hydroxide) in water Filter Produces limewater Lime water – used to test for carbon dioxide Calcium hydroxide + carbon dioxide  Ca(OH) 2 + CO 2  Calcium carbonate + water CaO 3 + H 2 O

Mortar – slaked lime + sand + water Uses - holds building materials together How – Lime in mortar reacts with carbon dioxide in air producing calcium carbonate Very strong

Cement - Limestone + clay Portland Cement – Limestone + clay + other minerals Uses – Modern house building How – Portland cement and sand mixed with water Left for a few days to set

Concrete – Stones/crushed rocks + water + cement + sand Very strong – resists forces Reinforced concrete – Poured around steel rods or bars

Glass – Powdered limestone + sand + sodium carbonate + strong heat Waterproof and light Available with different properties

Metals found in Earths crust, mostly combined with other elements, often oxygen

Metal ore – rock containing metal or metal compound

Native state – some metals so unreactive they are found as the element naturally

The reactivity series is the best way to extract a metal from its ore

Metals more reactive than carbon cannot be extracted from their ores using carbon

Many metals are found as oxides – combined with oxygen

Heat metal oxide with carbon, carbon removes the oxygen from the metal oxide to produce carbon dioxide Metal oxide + Carbon  Metal + Carbon dioxide

We call the removal of oxygen in this way a reduction reaction

Iron is extracted from iron ore by reducing it with carbon in a blast furnace

Haematite – most common iron ore: mainly iron (III) oxide and sand Coke – reducing agent: mainly carbon Limestone – removes impurities

C + O 2  CO 2 Hot air into blast furnace Coke burns Heats furnace Forms carbon dioxide gas

CO 2 + C  2CO Carbon dioxide reacts with coke Carbon monoxide gas formed

Fe 2 O 3 + 3CO  2Fe + 3CO 2 Carbon monoxide reacts with iron oxide Reducing it to molten iron Flows to bottom of furnace

Pig iron – produced from blast furnace Many impurities, mainly carbon

Remove impurities from pig iron – get pure iron – very soft

Metal that contains other elements - alloy

Iron alloyed with other elements - steel

Carbon steel – 0.03 – 1.5% carbon Cheapest steel Used – cars, knives, machinery, ships, containers, structural steel

High carbon steel – lots of carbon – very strong but brittle

Low carbon steel – soft and easily shaped, not as strong but less likely to shatter

Mild steel – less than 0.1% carbon – easily shaped – mass production of cars

Low-alloy steel – 1 – 5% other metals, e.g. nickel, chromium, manganese, vanadium, titanium, tungsten

Low alloy nickel – Resistant to stretching forces long span bridges, bike chains, military armour plating.

Low-alloy tungsten – good at high temperature High-speed tools

High alloy steel – Chromium 12 – 15% Sometimes some nickel too Strong, chemically stable Stainless steel DO NOT RUST !

Copper - very soft

Bronze – copper and tin plus other elements, e.g. phosphorus Low friction properties

Brass – Copper and zinc Hard Can be bent and shaped

Smart alloys Shape memory alloys When deformed they return to their original shape when heated

Shape memory alloys used in medicine – broken bones Dentistry - braces

Transition metal – Good conductors of electricity and heat hard, tough and strong Malleable high melting points

Copper extraction – Chemical – use sulfuric acid to produce copper sulfate solution

Copper extraction – smelting – heat copper ore strongly in air  crude copper Use impure copper as anodes in electrolysis cells 85% of copper produced like this

New ways – bacteria, fungi, plants to extract copper Cheaper, environmentally friendly alternatives to extraction methods

Aluminium and titanium useful as they resist corrosion

Al and Ti expensive to extract from ores as requires lots of energy ££££££££££££

Al extraction – electrolysis Pass an electric current through molten Aluminium oxide at high temperatures

Ti extraction – Displacement using sodium or magnesium Need to use electrolysis to produce these first

Electrolysis – very expensive, lots of energy due to high temperatures and electricity needed

Recycling Al is important Uses much less energy to produce same amount of recycled Al than extract it

Crude oil – mixture of many different chemical compounds Not very useful

Crude oil must be separated by distillation, into its different substances before it can be used.

Distillation separates liquids with different boiling points

Nearly all compounds in crude oil are made from atoms of hydrogen and carbon.

HYDROCARBONS

Most of the hydrocarbons in crude oil are ALKANES

General chemical formula of an alkane C n H 2n + 2 E.g. Methane CH 4 (C = 1, H = (2 x 1+ 2) = 4)

Alkanes – saturated hydrocarbons Contain as much hydrogen atoms as possible in their molecules

Separate crude oil using fractional distillation

Properties of each fraction depend on the size of the hydrocarbon molecules

Short molecules – Lower boiling point High volatility Low viscosity Flammable

Long molecules High boiling points Low volatility Viscous (thick) Smoky flame

Crude oil separated in a fractioning column Temperature decreases going up the column

Gases condense when they reach their boiling points

Hydrocarbons with smaller molecules – lower boiling points – collect at the cool top of the tower

Light crude oil – many smaller molecules Used as fuels More expensive than heavy crude oil

Hydrocarbons burn in air they produce carbon dioxide and water

Example: Propane + oxygen  carbon dioxide + water C 3 H 8 + 5O 2  3CO 2 + 4H 2 O

Impurities in fuels may produce other substances which may be poisonous and cause pollution

Sulfur dioxide – causes acid rain Most fuels contain some sulfur, which reacts with oxygen when burned

Hydrocarbons in car engine Not enough oxygen inside car cylinders, so instead of all changing to carbon dioxide, produces carbon monoxide instead.

Incomplete combustion

Nitrogen oxides : High temperatures in cars cause N and O in air to react Poisonous Trigger asthma Acid rain

Diesel cars – use larger molecule hydrocarbons Do not always burn completely Tiny particles are produced containing carbon and unburnt hydrocarbons Damaging when breathed in

Some substances released when fuels are burnt dissolve in droplets of water in air.

ACID RAIN

GLOBAL WARMING Carbon dioxide  gas greenhouse Reduces amount of heat lost by radiation

GLOBAL DIMMING Particulates reflect sunlight back into space

Catalytic convertors exhaust gases  catalytic converter  over transition metals  pass arranged with large surface area  oxide react  carbon monoxide and nitrogen produce carbon dioxide and nitrogen  reduces pollution

Flue gas desulfurisation (FGD) Power stations – sulfur dioxide reacts with quicklime to cut pollution

Gasohol Plants that make sugar produce ethanol by fermenting the sugar using yeast.

Can use this by adding to petrol Less pollution – burns more cleanly

Biodiesel Oilseed rape Plants take in carbon dioxide, even though they give it out when burnt Overall this cancels out

Energy can be produced from rubbish in an incinerator Disadvantages – produces dioxins which may be dangerous