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Flashcards by georgiahartxx, updated more than 1 year ago
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Created by georgiahartxx
over 9 years ago
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| Question | Answer |
| Give 2 advantages of quarrying. | ADVANTAGES -limestone is important to make concrete and other important materials -Provide employment for local people, which can be important for rural areas. |
| Give 2 disadvantages of quarrying | DISADVANTAGES -quarries are noisy and dirty -Quarries can be ugly places and spoil the natural beauty of landscapes, damaging tourism and upsetting local people. |
| Why is limestone so important? | It is an essential for important materials such as cement. |
| What is limestone made from? (include symbol) | Calcium carbonate (CaCO3) |
| Describe how limestone and other carbonates react with acid. | The acid reacts with the calcium carbonate to form a salt , water and carbon dioxide. |
| explain how limestone so badly affected by acid rain. | Old limestone buildings have being badly damaged and the fine details of many statues have been lost forever. |
| Explain WHY limestone is used to neutralise acidity in lakes. | because it is safer than adding an alkali because if you add too much limestone it will simply remain undissolved and settle out harmlessly. |
| Explain HOW limestone is used to neutralise acidity in lakes | The salt it forms (along with water and CO2) is neutral, not acidic. |
| Explain how limestone can be broken down by thermal decomposition. | The carbon atom takes 2 oxygen atoms to form CO2 and so the calcium atom is left with just one oxygen atom (calcium oxide) |
| Why will the mass after a thermal decomposition reaction appear to be lower? | because only the calcium oxide remains to be measured, the carbon dioxide is a gas, of which therefore escapes into the atmosphere. |
| Describe how calcium oxide can be turned into calcium hydroxide. | by reacting with water. |
| How is cement made? | Limestone is heated with clay to in a rotary kiln, thermal composition then occurs to give calcium oxide, which is mixed with other chemicals from the clay. The roasted product is then ground to form a light grey powder. |
| How is mortar made? | Cement is mixed with sand |
| Explain how concrete is made. | Cement is usually mixed with sand, aggregate, gravel, and water to form concrete. |
| Explain the environmental effects of the production of cement and concrete. | Making cement from limestone produces carbon dioxide, adding to britains carbon footprint however the concrete reabsorbs some of the CO2 as it continues to harden over a year or so |
| Give one disadvantage of building with concrete/cement | It is a slow, and expensive process because each block had to be carefully cut to shape and fitted into place by an expert craftsman. |
| Give 2 advantages of concrete as a building material | -powdered cement is easy to store and transport. -liquid concrete can be easily mixed on site |
| Why do we recycle metals? | -because it saves money -means that the reserves of metal in the ground last longer -avoids waste and pollution -lessens the effects os mining on people and the environment -saves energy |
| Explain why some rare metals were discovered before common metals. | Because the rare metals are a lot less reactive and so they are found as uncombined metals, whilst common metals are more reactive so they are tightly in compounds with other atoms such as oxygen making the metal difficult to extract. |
| How can less reactive metals be extracted?(e.g iron and copper) | DISPLACEMENT REACTIONS WITH CARBON Since carbon is more reactive than the metals, it displaces the metals from their compounds, pushing the metal out and taking its place. |
| Why is aluminium more expensive than less reactive metals? | Because since it is more reactive than carbon, you can't use the carbon reduction method to get aluminium from its ores, so it is extracted through electrolysis. |
| How is iron extracted from its ore? | Iron oxide, carbon, and limestone are tipped into the top of a blast furnace, where the temp is 1600°C, hot enough to reduce the ore and melt the iron |
| Why is limestone used in iron extraction? | Limestone is only there to remove impurities. |
| Give some of the useful properties of metals | -Strong (used to build machines and bridges) -Easy to shape (Car body panels are pressed out of sheet steel -High melting points (engines do not melt whilst they are in use) -Conduct heat and electricity (Used in electric wiring as heat sinks) |
| Give 2 advantages and one disadvantage for iron. | -hard and tough for machinery -Can be rolled/cut/pressed into shape for anything -it rusts |
| Give 3 advantages for copper | -good electrical conductor -soft and bendy (good for electric wires) -not very reactive so does not react with water, or corrode like iron and steel. |
| What is a transition metal? | A metal good for everyday uses, (in the central block of the periodic table) |
| Explain why modern day aircrafts are made of aluminium and not steel. | Because aluminium is a lot less dense than steel, so if an aircraft was made of steel, it would use too much energy to get off the ground. Aluminium can therefore be used to make a plane strong and light enough to be able to fly. |
| Explain why jets are made from titanium and not aluminium. | Because it is as strong as steel but less dense, but it is denser than aluminium, titanium also has a higher melting point than steel. |
| What is a steel alloy? | A mixture of iron, with carbon or otter metals |
| Describe the main compounds in crude oil. | Hydrocarbons (molecules made from hydrogen and carbon only) |
| Explain why alkanes are called saturated hydrocarbons | Because all alkanes contain only single bonds. |
| What is the general formula for alkanes? | CnH2n+2 |
| Explain what mixtures are and how they differ from compounds. | Mixtures consist of two or more elements or compounds, however they are not chemically combined like in compounds. |
| What is fractional distillation typically used for? | to obtain a liquid from a mixture of liquids that dissolve into one another. |
| Explain the process of fractional distillation. | The mixture is placed over a bunsen burner, and the liquid with the lower boiling point evaporates first, its vapours are led away, then cooled and condensed, leaving the rest of the mixture behind. |
| Describe how crude oil can be separated. | It is led into the bottom of a fractionating column, the vapours cool down as they rise through it, when the vapours reach a part of the column that is cool enough, they condense, the liquids fall into a tray and is piped out, this is a continous process. |
| During oil fractionation, which alkanes condense where? | Alkanes with the longest chains condense near the bottom of the column, those with intermediate sized chains condense further up, and alkanes with the shortest chains remain as gases. |
| Explain the advantages and disadvantages of using short chained alkanes as fuels | Since they are gases at room temp, they are easily piped to where they are needed however they are difficult to store, so they are often stored under pressure as liquids. |
| Explain the advantages of using alkanes with intermediate chains as fuels. | They are liquids at room temp so they are stored easily and they can easily be piped to where they are needed, they are also less viscous than shorter chained alkanes, meaning that they can flow more easily. |
| Explain what complete combustion is (to coal). | Happens when the coal burns in a plentiful supply of air, so its carbon is oxidised into CO2. |
| Explain when incomplete combustion happens (to coal). | Happens if the air is not plentiful, as the coal burns, its carbon may be oxidised into carbon monoxide (2CO) |
| Explain how natural gases burn. | The natural gas oxidises its carbon to carbon dioxide, and its hydrogen to water vapour e.g. methane+oxygen=carbon dioxide+water |
| What are particulates and what do they contain? | Solid particles produced when fuels burn, they contain carbon and unburned fuel and are deposited as soot. |
| Explain the consequences of particulates | High levels of particulates in polluted air can lead to early deaths and extra cases of asthma, bronchitis and other respiratory diseases. |
| Explain the greenhouse effect | Greenhouse gases, such as CO2 and water vapour, absorb infrared radiation and stop it escaping into space, without this life as we know it would not exist. |
| Explain how carbon dioxide contributes to global warming. | CO2 is released when hydrocarbon fuels burn, our use of such fuels is releasing CO2 faster than it can be removed by natural process, extra CO2 contribues to an enhanced greenhouse effect, leading to global warming. |
| Explain what causes global dimming | Happens because of particulate reflecting sunlight back into space. Water droplets condense around the particulates, forming clouds that are more reflective than normal clouds. |
| Explain the consequences of global dimming. | It has reduced the amount of evaporation, interfering with the water cycle and possibly causing droughts. |
| Describe the ways in which sulfur dioxide emissions may be reduced. | It is absorbed by powdered calcium carbonate or damp calcium hydroxide, making calcium sulfate, a less harmful product. Low-sulfur diesel and petrol are also available at filling stations, releasing less sulfur dioxide when they burn. |
| What is cracking and why is it done? | Cracking involves breaking down C-C covalent bonds to solve th supply and demand problem. |
| How is cracking done? | the hydrocarbons are heated to vaporise them, they are then passed into a hot catalyst, cracking therefore produces shorter alkanes and alkenes. |
| What are the alkanes and alkenes used for after cracking? | alkanes are used to meet the demand for fuels such as petrol and the alkenes are used to make plastics. |
| What type of reaction is cracking? | a thermal decompostition reaction |
| What are polymers made from? | Polymers are large molecules made from lots of MONOMERS (small molecules) |
| What is ethanol? (include symbol) | the alcohol found in alcoholic drinks (C2H5OH) |
| Describe how emulsions form in full fat milk. | It comprises of a watery liquid mixed with tiny droplets of butterfat, after the mixture was shaken vigourously. |
| Describe the properties of emulsifiers. | One end od the molecule is hydrophobic, so it dissolves in the oil in the emulsion, the other end of the molecule is hydrophilic, so it dissolves in the water in the emulsion. |
| Describe the bonds in unsaturated vegetable oils. | Double bonds (C=C bonds) |
| How does bromine work? | An orange solution of bromine, turns colourless when it is mixed with alkenes, or with unsaturated vegetable oils. |
| Describe the structure of the earth | -the atmosphere- a layer of gases -the crust- a thin layer of rocks -mantle- a thick layer of rocks -the core- a central ball of iron |
| describe what tectonic plates are | the lithosphere (outer part of the earth) is cracked into a number of huge pieces, these are tectonic plates |
| Explain where earthquakes and volcanoes are most likely to occur | at the boundaries between tectonic plates, as the plates move, friction between them can cause sudden jerks, producing earthquakes |
| Describe how gases in the air can be separated by the fractional distillation of liquified air. | air is cooled until is it a liquid at about -200°C as it warms up again the separate substances boil at different temperatures and can be collected separately. |
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