Core Chemistry Big Teach 2: Materials From the Earth

Key terms used in exam questions Quarry– Where we dig limestone

Rocks Sedimentary Metamorphic Igneous Examples: Marble Examples: Chalk and Limestone How was it formed? Sediments fall to bottom of the sea Over millions of years Layers compact Rock formed Things to know: They contain fossils They erode easily Examples: Marble How is it formed? Sedimentary rocks are put under heat and pressure Things to know Limestone turns into Marble The heat comes from the magma Examples: Granite How is it formed When Lava cools Things to Know Marble turns into granite If the laveacools quickly it contains small crystals If it cools slowly It contains large crystals

The “Limestone Cycle” 08/11/2018 08/11/2018 CO2 Calcium Carbonate (limestone) CO2 Step 4: add CO2 Step 1: heat Calcium Hydroxide solution Calcium Oxide Step 3: add more water and filter Step 2: add a little water H2O Calcium Hydroxide H2O H2O H2O

Remember – They are all the same thing Limestone Calcium Carbonate CaCO3

Remember – They are all the same thing Limewater Calcium Hydroxide Ca(OH)2

Remember – The Test for carbon dioxide Bubble the gas through limewater Lime water goes cloudy

Calcium Carbonate – The neutraliser Why is it sprayed onto fields Neutralise acidic soil Why is it sprayed onto waste gases from chimneys Neutralise acidic waste gases Why is it taken as an indigestion remedy Neutralise excess acid in stomach

Limestone 08/11/2018 08/11/2018 Limestone has a number of uses when it undergoes chemical reactions. There are two reactions to know: 1) Firstly, a THERMAL _________________ reaction is used to break the calcium carbonate down into calcium ______ and _______ __________: 2) _____ is then added to produce calcium __________: Calcium carbonate calcium oxide + carbon dioxide HEAT Calcium oxide calcium hydroxide WATER Words – hydroxide, decomposition, carbon dioxide, water, oxide

  Indicative Content Mark     *(i) A description including some of the following Step A heat limestone strong heat / with roaring Bunsen flame thermally decompose limestone to form calcium oxide and carbon dioxide allow to cool word eqn: calcium carbonate → calcium oxide + carbon dioxide bal eqn: CaCO3 → CaO + CO2 Step B add water to calcium oxide calcium oxide swells/cracks/steams until in excess white solid dissolves in water filter mixture to remove unreacted calcium hydroxide colourless solution formed word eqn: calcium oxide + water → calcium hydroxide bal eqn: CaO + H2O → Ca(OH)2           (6)

After its use it can be turned into a lake Damages habitats   Advantages of a limestone quary Disadvantages of a limestone quary Social (people living in the local area)  Provides jobs     Noisy Dusty Evironmental  After its use it can be turned into a lake  Damages habitats Economic (money)  Limestone is a valuable resource  Loss of tourism

Limestone + sand + soda glass 08/11/2018 Limestone is a __________ rock made up of mainly calcium carbonate. It’s cheap and easy to obtain. Some uses: 1) Building materials – limestone can be quarried and cut into blocks to be used in _______. However, it is badly affected by ____ ____. 2) Glass making – glass is made by mixing limestone with _____ and soda: Limestone + sand + soda glass 3) Cement making – limestone can be “roasted” in a rotary kiln to produce dry cement. It’s then mixed with sand and gravel to make _______. Words – sand, building, sedimentary, concrete, acid rain

Uses of these Calcium compounds 08/11/2018 Calcium carbonate (limestone), calcium oxide and calcium hydroxide have a number of uses: 1) Neutralising acidic soil – calcium carbonate, calcium hydroxide and calcium oxide are _______ and can be used to ________ soil acidity to help ______ growth. 2) Removing pollutants – calcium carbonate can be used as a “_______” to remove acidic gases from a coal-fired power station’s waste products, helping prevent ____ _____. Words – acid rain, alkaline, plant, scrubber, neutralise

An explanation including some of the following calcium carbonate/limestone · for buildings · making roads · treating acid soil/ treating acid lakes · in power station chimneys · making cement · making concrete and mortar · making glass · extracting iron · heating (to make calcium oxide) · making sodium carbonate · as a filler in plastics and paper · in paints · toothpaste · gravestones · statues, decorative stonework · indigestion remedies · railway ballast · bread making calcium oxide · treating acid soil · in power station chimneys · making calcium hydroxide (when water added)calcium hydroxide · treating acid soil · making limewater