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47 Cards in this Set
- Front
- Back
- 3rd side (hint)
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How many electrons in each shell / energy level? |
2, 8, 8 |
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A compound formed from a metal and a nonmetal consists of ___ |
Ions. The metal atoms lose electrons to form positive ions, and the nonmetal atoms gain electrons to form negative ions. The opposite charges mean they're strongly attracted. |
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The limestone cycle |
CaCO3 --HEAT--> CaO + CO2 CaO + H2O ---> Ca(OH)2 + HEAT Ca(OH)2 + CO2 ---> CaCO3 |
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Uses of calcium hydroxide Ca(OH)2 |
An alkali that can be used to neutralize acidic soils in fields, faster than powdered limestone. Adding water forms limewater (aq) Tests for the presence of carbon dioxide; it turns cloudy when carbon dioxide is bubbled through it because calcium carbonate is being formed. |
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Uses of powdered limestone |
Powdered limestone can be heated in a kiln with powdered clay to make cement. Cement + water --> mortar* Cement + aggregate --> concrete *used for sticking bricks together |
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Advantages of limestone quarrying |
+limestone is widely available and cheap +also easy to cut +hard-wearing but attractive +concrete is a cheap and easy way of constructing buildings +limestone, concrete, and cement don't rot and are fire resistant +concrete doesn't corrode |
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Disadvantages of limestone quarrying |
-Quarrying leaves ugly, permanent holes -the process (inc. explosions) creates noise and dust -waste material produces tips -lots of dust from cement factories causes breathing problems -energy needed is likely to come from burning fossil fuels |
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Reduction |
When an ore is reduced oxygen in removed by adding carbon to it, however this only works with metals lower than carbon on the reactivity series (less reactive) |
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Electrolysis |
Electrolysis is the breaking down of a substance using electricity. It requires a liquid to conduct the electricity, called the electrolyte. The electrolyte has free ions - these conduct the electricity. Electrons are taken away by the positive anode and given away by the negative cathode. As ions lose or gain electrons they become atoms or molecules and are released. |
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Displacement |
If you put a reactive metal into a dissolved metal compound, the reactive metal will bond more strongly to the nonmetal part of the compound, and pushes out the less reactive metal. Eg, copper sulfate + iron --> iron sulfate + copper +scrap iron is cheap and copper is quite expensive |
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Bioleaching |
Bacteria gets energy from the bond between copper and sulfur, separating the copper from the ore in the process. The leachate (solution produced) contains copper which can be extracted by filtering. |
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Phytomining |
When plants are grown in soil that contains copper, the copper gradually builds up in the leaves because the plants can't use it. The plants can be harvested, dried and burned in a furnace, and the copper can be collected from the ash leftover. |
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Advantages of mining ores |
+useful products can be made +provides the local area with jobs and money |
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Disadvantages of mining ores |
-causes noise -scars the landscape -loss of habitats -deep mine shafts can be dangerous -mining/extracting uses a lot of energy, mainly from burning fossil fuels -important to conserve finite fossil fuels -burning fossil fuels also contributes to acid rain, global dimming and climate change |
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Advantages of recycling metals (No disadvantages) |
+uses a fraction of energy used to mine/extract them money +conserves finite resources +consequently saves money +conserves finite resources +reduces waste for landfills, which take up space and pollute the surroundings +reduces waste for landfills, which take up space and pollute the surroundings |
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General properties of metals |
•strong (hard to break) but can be bent or hammered into different shapes •great at conducting heat •conduct electricity well |
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Properties of copper |
•good conductor of electricity •hard and strong but can be bent •doesn't react with water Ideal for electrical wires |
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Properties of aluminium |
•corrosion-resistant •low-density •pure aluminium isn't very strong, but forms hard, strong alloys Used in transportation and packaging |
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Properties of titanium |
•corrosion-resistant •low density •very strong Used in aerospace industry (eg, airframes and engines) because of lightweight, strength, and ability to withstand high temperatures |
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Metal corrosion |
Some metals corrode when exposed to air or water, so they need to be protected. If they corrode, they lose their strength and hardness. |
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Metal fatigue |
When metals are repeatedly stressed/strained over time, metal fatigue leads to them breaking , which can be very dangerous (eg, in planes) |
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Alloys |
Different elements have different sized atoms, so when an atom such as carbon is added to pure iron, the smaller carbon atoms will change the layers of pure iron atoms, making it more difficult for them to slide over each other, making alloys harder. |
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Alloys of iron (steel) |
Low carbon steel = easily shaped, used in car bodies High carbon steel = hard + inflexible, used for cutting tools (blades) + bridges Stainless steel (with chromium and sometimes nickel) = corrosion-resistant, used in cutlery and containers for corrosive substances |
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Electrolysis to purify copper |
The cathode starts as a thin piece of pure copper The anode is a large amount of impure copper, which will dissolve Electrons are taken away from copper atoms at the anode, causing them to go into the solution as Cu(2+) ions. Cu(2+) ions near the cathode gain electrons and turn back into copper atoms The impurities are dropped off at the anode as a sludge, whilst pure copper atoms bond to the cathode, which builds into a thicker piece of pure copper |
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What is the electrolyte (definition + common examples) |
A liquid to conduct the electricity Often metal salt solutions from the ore (copper sulfate) Or molten metal oxides |
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Anode / cathode |
Electrons are taken away by the positive anode and given away by the negative cathode Cath(y) is dead so in the negative world Anny is alive (positive world) |
Anode = positive Cathode = negative |
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Displacement reaction |
If you put a reactive metal into a solution of dissolved metal compound, the more reactive metal will bond more strongly to the non metal part of the compound and pushes out the less reactive metal |
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Bioleaching + phytomining vs traditional methods of extraction |
Traditional methods are quite damaging to the environment These methods have a smaller impact, but they're slower |
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Bioleaching |
Bacteria gets energy from the bond between copper and sulfur, separating the copper from the ore in the process. The leachate (solution produced) contains copper, which can be extracted (eg) by filtering |
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Phytomining |
Growing plants in soil that contains copper. The plants can't use or get rid of the copper so it gradually builds up in the leaves. The plants are harvested, dried and burned in a furnace. Copper can be collected from the ash left in the furnace |
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Why use bioleaching / phytomining |
The supply of copper-rich ores is limited, so it's important to recycle as much copper as possible Demand for it is high, may lead to shortages. Extract from low grade ores / or from waste produced when copper is extracted |
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Metal extraction (+) (-) |
+useful products can be made +provides local people with jobs, brings money to the area, services (health, transport) can be improved -noise -scarring of the landscape -loss of habitats -deep mine shafts can be dangerous for a long time after they've been abandoned |
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Recycling metals |
Mining / extracting requires a lot of energy, mostly from fossil fuels. Fossil fuels are running out, important to conserve them. Burning them contributes to acid rain, global dimming, global warming Recycling metals only uses a fraction of the energy needed to mine / extract new metal. Energy costs, so recycling saves money Finite amount of each metal in Earth, so they need to be conserved Reduces amount send to landfill (takes up space + pollutes surroundings) |
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Properties of most metals |
•strong (hard to break) but can be hammered or bent into different shapes •great at conducting heat •conduct electricity well |
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Uses of Metals |
Strength + 'bend ability' -> bridges, car bodies. Something heat needs to travel through, eg, saucepan base Conductivity -> electrical wires |
Especially transition metals |
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Copper |
Good conductor of electricity (electrical wires) Hard + strong but can be bent Doesn't react with water |
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Aluminium |
Corrosion resistant Low density Isn't particularly strong, but forms hard, strong alloys |
Aeroplane (strong, bendable, light) |
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Titanium |
Low density Very strong Corrosion resistant |
Replacement hips (doesn't corrode, very strong, light weight) |
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Metal flaws |
Metals are useful structural materials, but some corrode when exposed to air and water, so they need to be protected (eg, painting) Metal fatigue (repeated stresses + strains) -> metals breaking = dangerous (eg, in planes) |
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Iron from blast furnace |
Only 96% iron (rest is impurities like carbon). Used as cast iron. Ornamental railings, but not much else bc it's too brittle. |
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What happens to iron from blast furnace |
All the impurities are removed. This pure iron has a regular arrangement of identical atoms, which makes the iron soft and easily shaped. Too bendy for most uses. |
Purified |
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Alloys of iron |
LC steel = easily shaped -> car bodies HC steel = very hard, inflexible, -> blades for cutting tools, bridges Stainless steel (+chromium, nickel) = corrosion resistant -> cutlery, containers for corrosive substances |
Steels |
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Why are alloys harder than pure metals |
Different elements have different sized atoms. When carbon is added to pure iron, the smaller carbon atoms with disrupt the layers of pure iron atoms, making it more difficult for them to slide over each other |
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Crude oil is a mixture of hydrocarbons |
No chemical bonds between different parts of the mixture, so all the different hydrocarbon molecules aren't chemically bonded to each other = all keep original properties (eg, condensing points) |
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Properties of a mixture |
Are just a mixture of the properties of the separate parts |
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The shorter the molecules... |
Less viscous More volatile (lower boiling point) More flammable |
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Uses of hydrocarbons depend on their properties |
Volatility - refinery gas fraction has lowest boiling point, so is used as bottled gas. Petrol = higher boiling point. Liquid (ideal for storing in fuel tank) flows to the engine where vaporized Most viscous -> lubricating engine parts and covering roads |
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