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IONIC BONDING metal & non-metal = ions metal lose electrons = positive ions/ non-metal gain electrons = negative
COVALENT BONDING non-metals = molecules atoms share electrons to fill outer shells
Calcium carbonate (limestone) thermal decomposition = calcium oxide + carbon dioxide calcium carbonate + sulfuric acid → calcium water
calcium oxide + water → calcium hydroxide = alkali neutralise acidic soil - faster than limestone test for CO2 - bubble gas through limewater solution (dilute calcium hydroxide) = cloudy solution of calcium carbonate from CO2
Heated powdered limestone & powdered clay = cement Cement mixed with sand & water = mortar (stick bricks) (can add calcium hydroxide) Mix cement with sand & aggregate (water & gravel) = concrete
Quarrying limestone = scars landscape big ugly holes noise & dust destroys habitats transported away (lorries) Pollution cement factories = dust = breathing problems energy for cement & quicklime (calcium oxide) = fossil fuels
Houses & roads/dyes paints, medicines Neutralise - acidic soil & rivers/lakes (acid rain) Neutralise sulfur dioxide in power station chimneys Jobs = money into local economy = local improvements
Limestone & concrete - building materials widely available & cheaper than granite/marble more hard-wearing than marble but attractive concrete poured into moulds to make blocks which join together. Quick & Cheap. But Unattractive. Limestone/concrete/cement don't rot when wet like wood. Not gnawed by insects. Fire-resistant. Concrete doesn't corrode. Low tensile strength - can crack. Stronger if reinforced with steel.
Thermal decomposition - when one substance chemically changes into at least two new substances when heated
Chemistry
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