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43 Cards in this Set
- Front
- Back
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How do we get information about the earth's core? |
Monitoring seismic waves produced by earthquakes and man-made equations |
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Which is denser: continental or oceanic plate? |
Oceanic |
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When was Wegner's theory of continental drift finally accepted and why? |
1960 because of new evidence of sea floor spreading |
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What kind of rock is formed from runny lava? |
Iron-rich basalt rock |
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What kind of rock is formed by thick lava? |
Silica-rich rhyolite rock |
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What is cement made of? |
Limestone and clay |
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What are iron and aluminium made of? |
Iron ore and aluminium ore |
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Name a sedimentary rock |
Sandstone, limestone, chalk, clay |
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Name a metamorphic rock |
Marble (from limestone), slate (from clay) and schists (from sandstone). |
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Name a igneous rock |
Basalt, granite |
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How are sedimentary rocks formed? |
Soft sediments compressed together |
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What are metamorphic rocks formed? |
Sedimentary rocks changed by heat and pressure- interlocking mosaic of carbonate crystals. |
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How are igneous rocks formed? |
Magma cools and solidifies- interlocking crystals |
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What is thermal decomposition? |
One substance breaks down to make at least 2 new |
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Complete the equation for the decomposition of calcium carbonate
calcium carbonate--> ? + ? |
Calcium oxide + carbon dioxide |
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What are the advantages of reinforced concrete? |
Harder and more flexible- especially under tension |
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Advantages of recycling copper? |
-Low melting point so energy costs are low -Reducing need for mining -Keeps cost of copper down |
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Disadvantages of recycling copper? |
-Difficult to separate in electric equipment -Pure must not be mixed with scrap -Fewer mining jobs -Separating process causes pollution -Difficult to persuade people to actually recycle |
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Explain how we use electrolysis to purify copper |
Impure copper is the anode (positive) and a sheet of pure copper the cathode (negative). The anode loses mass as the impurities dissolve off and cathode gains mass as pure copper plates onto it. |
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What reaction happens at the anode in purification of copper? |
Copper atoms lose electrons to form Cu2+ ions Cu - 2e- => Cu2+ |
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What reaction happens at the cathode in purification of copper? |
Cu2+ + 2e- => Cu |
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What are alloys? |
Mixtures containing at least one metal |
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What are smart alloys and what is an example of one? |
They return to their original shape after being heated to a certain temperature. Nitinol, used to make spectacle frames. |
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Only iron and steel rust, what do other metals do? |
Corrode |
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What accelerates the rusting process? |
Acid rain and salt water |
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What kind of reaction is rusting? |
Oxidation because iron reacts with oxygen, forming an oxide |
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What is the word equation for rusting? |
iron+oxygen+watere-->hydrated iron(III) oxide |
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Why does aluminium not corrode? |
It has a protective layer of aluminium oxide |
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Name some properties of metals |
Malleable, lightweight, dense, strong, rigid |
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Advantages of recycling old car parts? |
-it's law that a certain amount of materials in new cars must be sourced from recycled parts -saves finite metals used in manufacture -less crude oil for new plastics -less landfill filling -fewer toxic materials disposed of (eg. batteries) |
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Disadvantages of recycling old car parts? |
-fewer mining jobs -difficult to separate parts -some separating techniques cause pollution -sometimes expensive |
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Explain the Haber process |
Nitrogen from air and hydrogen from natural gas or cracking oil factions go through a compressor and into a 450 degree reaction vessel. They react over an iron catalyst to become ammonia which is then condensed. Any left over gas is recycled. |
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What is ammonia's main use and where do we get it from? |
Haber process: for fertalisers. |
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Word equation for making ammonia? |
nitrogen + hydrogen <---> ammonia |
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What are the best conditions for the Haber process? |
-450 degrees increases reaction rate - Iron catalyst increases reaction rate - 200 atmospheres pressure increase percentage yield |
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What determines concentration of an acid? |
Concentration of H+ ions |
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How do fertilisers increase crop yield? |
-Replace essential elements used by previous crop or providing extra -Nitrogen that is incorporated into plant protein resulting in increased growth |
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Explain the process of eutrophication. |
-Fertilisers wash off fields into water -Increase nitrate and phosphate levels -Algal bloom because of this -Algae blocks sunlight so underwater plants die -Aerobic bacteria use up oxygen to decay plants -No oxygen for fauna |
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How do you make a fertiliser? (sulfuric and ammonia solution) |
-Alkali treated with acid using indicator to find out quantities needed beforehand -Acid&alk are redone without indicator so as not to be contaminated -They react to produce neutral ammonium sulfate -Fertiliser is heated to evaporate water then the crystals left are filtered off |
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What are the two ways in which salt can be mined? |
-From the ground as rock salt -Solution mining by pumping in water and extracting the saturated salt solution (which can lead to subsidence where land above the mine can sink) |
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Explain how brine is separated |
Electrolysis. Na+ and H+ (hydrogen) goes to cathode and Cl- and OH- (chlorine gas) at anode, they then leave through the corresponding exits. Care must be taken to ensure that electrolytes do not dissolve and the products don't react before extraction. |
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Name a use of sodium hydroxide and chlorine |
Bleach, solvents, plastics, paints, soaps, medicines, food |
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what |
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