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C1

ruthkeat Chemistry GCSE Inglês 186 flashcards

Flashcards do conjunto (186)

  1. 1What are all substances made up of?Atoms
  2. 2How many types of atoms make up an element?One
  3. 3What are the columns on the periodic table called?Groups
  4. 4Describe the structure of an atom.Atoms have a tiny nucleus surrounded by electrons. The nucleus of an atom is made of two types of particle, protons and neutrons.
  5. 5What are compounds?When elements react, their atoms join with atoms of other elements and a compound is formed when two or more elements combine together.
  6. 6What are the charges of protons, neutrons and electrons?Protons-Positive
    Electrons-Negative
    Neutrons-No charge
  7. 7Why are atoms neutral/no charge?An atom has no overall charge because the number of protons is equal to the number of electrons and their charges are equal and opposite.
  8. 8What does the atomic number say about an element?It is equal to the number of protons in the nucleus of its atoms. It is also the number of electrons in an atom of the element.
  9. 9What is the mass number?The sum of the protons and neutrons in the nucleus of an atom.
  10. 10What can energy levels be represented as?Shells
  11. 11What group are the atoms of the unreactive noble gases in?0
  12. 12The atoms of the unreactive noble gases all have ______ arrangements of electrons.very stable
  13. 13Electrons in atoms are in ______ that can be represented by ______..energy levels
    shells
  14. 14Electrons in the lowest energy level are...In the shell closest to the nucleus.
  15. 15Which energy levels do electrons occupy first?The lowest
  16. 16All the elements in the same group of the periodic table ______ number of electrons in their highest energy level (outer shell).the same
  17. 17Group 1 elements react quickly with....water and oxygen
  18. 18How many electrons does each shell hold?2, 8, 8
  19. 19Group 1 metals react vigorously with water to produce...An alkaline solution and hydrogen gas.
  20. 20The group 1 elements react rapidly with oxygen to form...metal oxides.
  21. 21What are the elements in group 0 known as?The noble gases
  22. 22What happens when a metal reacts with a non-metal?Ions are formed. Metals atoms lose one of more electrons to form positively charged ions. Non-metal atoms can electrons to form negatively charged ions.
  23. 23Oppositely charge ions ____ each other strongly and compounds of metals bonded to non-metals have _______attract
    ionic bonds
  24. 24What does the formula of an ionic compound show?The simplest ratio of ions.
  25. 25What type of bonds do compounds of non-metals have?Covalent bonds
  26. 26What does the formula of a molecule show?The number of atoms in the molecule.
  27. 27What happens when non-metals combine?Their atoms share electrons to form covalent bonds and molecules are formed.
  28. 28How can covalent bonds be shown?As lines between the atoms that have been bonded together.
  29. 29What happens to atoms in chemical reactions?They re-arrange themselves to form new substances, the products.
  30. 30The number and type of atoms ______ before and after the reaction because....-The same
    -Atoms are neither created nor destroyed in chemical reactions
  31. 31The mass of the products is _____ the mass of reactantsthe same as
  32. 32What is ionic bonding?Metals and non-metals
    The metals lose electrons.
    The non-metals gain electrons.
  33. 33What is covalent bonding?Non-metals and non-metals
    Sharing of electrons
  34. 34What is the mass number? What is the atomic number?Sum of protons and neutrons
    Number of protons (also number of electrons)
  35. 35What type of rock is limestone?A sedimentary rock
  36. 36What is limestone mainly made of?Calcium carbonate
  37. 37What are some uses of limestone?-As a building material
    -To make calcium oxide
    -To make cement
  38. 38How is concrete made?By mixing cement with sand, aggregate and water.
  39. 39What does thermal decomposition mean?Breaking down by heating
  40. 40Limestone can be eroded by ________ because....Acid rain
    The calcium carbonate in the limestone reacts with acids in the rain.
  41. 41What happens when calcium carbonate is heated strongly and what is this called?It decomposes to make calcium oxide and carbon dioxide. This is done on a large scale in lime kilns and is called thermal decomposition.
  42. 42When calcium carbonate is heated, what two compounds does it break down into?Calcium oxide and carbon dioxide
  43. 43How do you make mortar?By mixing dry cement + sand + water and is used to hold bricks and blocks together in buildings.
  44. 44How do you make cement?Limestone is mixed with clay and heated strongly in a kiln. The product is ground up to make a fine powder.
  45. 45What happens to metal carbonates when they are heated strongly enough?They decompose to the metal oxide and carbon dioxide
  46. 46What happens when carbonates react with acids?They produce a salt, water and carbon dioxide.
  47. 47What is calcium hydroxide solution called?Limewater
  48. 48What is limewater used for?To test for carbon dioxide. The limewater turns cloudy when carbon dioxide is present to produce insoluble calcium carbonate.
  49. 49Carbonates react with dilute acid to form...Carbon dioxide (and salt and water)
  50. 50What is produced when water is added to calcium oxide?Calcium hydroxide
  51. 51What is calcium hydroxide used for and why?It is an alkali so can be used to neutralise acids. For example, farmers use it to neutralise acidic solutions and in industry to neutralise acidic gases.
  52. 52What is produced when calcium hydroxide reacts with carbon dioxide?Calcium carbonate
  53. 53Calcium hydroxide is not very soluble/soluble in water but......not very soluble
    dissolves slightly to make limewater
  54. 54What are the differences between cement, mortar and concrete?Cement is made from limestone and clay and is used to make mortar.
    Mortar is cement mixed with sand and water and is used to hold bricks and blocks together.
    Concrete is cement mixed with sand water and aggregate used to make blocks, beams, buildings and roads.
  55. 55What is aggregate?Stones or crushed rock
  56. 56What are the negatives of cement works?They use large areas of land and a lot of energy.
  57. 57Advantages and disadvantages for an area in which limestone is quarriedMore employment opportunities for local people, more customers and trade for local businesses, improved roads
    Dust and noise, more traffic, loss of habitats for wildlife
  58. 58What is a metal ore?Rock that contains enough of a metal or a metal compound to make it worth extracting
  59. 59Where are metals usually found?In the Earth's crust
  60. 60How is it decided which way metal is extracted?Depending on the reactivity.
  61. 61What is a reduction reaction?The removal of oxygen from a metal oxide
  62. 62How are metals less reactive than carbon extracted?They are extracted from their oxides by heating them will carbon.
  63. 63How is iron produced from iron oxide?It is reduced at high temperatures in a blast furnace using carbon.
  64. 64What is the problem with iron from a blast furnace?It contains about 96% iron and the impurities make it hard and brittle and so it only has a few uses as cast iron
  65. 65How do you make pure iron and what is the problem with pure iron?Remove all carbon and impurities but it this is too soft for many uses.
  66. 66What is the main use of iron?It is converted into alloys called steel.
  67. 67What do steels contain?Carefully controlled quantities of carbon and other elements.
  68. 68What is an alloy?German
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    Home > Science > OCR Gateway (Pre-2011) > Rocks and metals > Metals and alloys
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    Science
    Metals and alloys
    Page: 12Back
    Alloys
    An alloy is a mixture of two elements, one of which is a metal. Alloys often have properties that are different to the metals they contain. This makes them more useful than the pure metals alone. For example, alloys are often harder than the metal they contain.
  69. 69How are metals that are more reactive than carbon extracted?By electrolysis of molten compounds.
  70. 70What is the difference between low and high carbon steels?Low: Easily Shaped
    High: Hard
  71. 71What are stainless steels?Steels that resist corrosion.
  72. 72What are the properties of aluminium?-Has a low density
    -Resistant to corrosion
    -Extracted by electrolysis of molten aluminium oxide
    -Expensive to extract
    -Pure it is not very strong but alloys are stronger and harder
    -Good conductor of heat and electricity
    -Can be polished to give a highly reflective surface
  73. 73Uses of aluminium-Drinks cans
    -Roofing material
    -Aircrafts
    -Lightweight vehicles
    -Ladders
    -Overhead power cables
    -Boilers, cookers, cookware
    -Greenhouse, window frames
  74. 74What are the properties of titanium?-Resistant to corrosion
    -Very strong
    -Low density
    -Can be reduced by carbon but the metal reacts with carbon making it brittle
    -Not very good at conducting heat or electricity
    -Non-toxic
    -High boiling point and low melting point
  75. 75Uses of titanium-Aircraft engines
    -surgical implements and implants, such as hip joint replacements
    -Parts of boats
  76. 76Why are aluminium and titanium expensive to extract?Extracting them involves many stages and requires large amounts of energy
  77. 77How can copper be extracted from copper-rich ores and how can this impure copper then be purified?By heating the ore strongly in a furnace. This is called smelting. It can be purified by electrolysis.
  78. 78Why is smelting and purifying copper ore expensive?It requires huge amounts of heating and electricity.
  79. 79What is the problem with copper rich ores?They are a limited resource.
  80. 80What are the new ways to extract copper from low-grade ores?Bioleaching and phytomining
  81. 81What is phytomining?Using plants to absorb copper compounds from the ground as they grow. The plants are burned and produce ash from which the copper can be extracted.
  82. 82What is bioleaching?Using bacteria to produce solutions containing copper compounds. A solution containing bacteria is mixed with a low-grade ore. The bacteria convert the copper into solution where it can be easily extracted.
  83. 83What three ways can be used to produce copper metal from its compounds?Smelting, electrolysis and displacement
  84. 84How does displacement work to produce copper metal from its compound?Solutions of copper compounds are reacted with a metal that is more reactive than copper such as scrap iron.
  85. 85Where are the transition metals found on the periodic table?In the middle block
  86. 86What are the properties of transition metals?-All metals
    -Good conductors of heat and electricity
    -Have high melting points except mercury
    -Strong but can be bent or hammered into shape
  87. 87Common uses of transition metals-Building materials
    -Vehicles
    -Containers
    -Pipes
    -Wires
  88. 88Properties and uses of copper-Doesn't react with water
    -Good conductor of heat
    -Can be bent but hard enough to keep its shape
    -Good conductor of electricity
    -Electrical wiring, Making pipes and tanks in water and heating systems
  89. 89Examples of copper alloysBronze and brass
  90. 90Why is the gold used for rings mixed with other metals?To make it harder
  91. 91What is an environmental problem with mining for metal ores?It involves digging up and processing large amounts of rock which can produce large amounts of waste material and effect large areas of the environment.
  92. 92What are the benefits of recycling metals?-Saves the energy needed to extract the metal
    -Less ore needs to be mined
    -Less fossil fuel is needed to provide the energy to extract the metal from its ore
  93. 93Benefits of using metals in construction-They are strong
    -They can be bent into shape
    -They can be made into flexible wires
    -They are good electrical conductors
  94. 94Drawbacks of using metals in construction-Obtaining metals from ores causes pollution and uses up limited resources
    -Metals are more expensive than other materials such as concrete
    -Iron and steel can rust
  95. 95What is crude oil?A mixture of a many different compounds.
  96. 96How can we separate a mixture of liquids?By distillation
  97. 97What are fractions?Liquids with different boiling ranges separated from a mixture of liquids (crude oil)
  98. 98What are most of the compounds in crude oil?Hydrocarbons
  99. 99What does it mean when a compound is a hydrocarbon?Their molecules contain only hydrogen and carbon.
  100. 100What is the general formula for alkanes?C*n*H*2n+2
    *(all after it is below the H)
  101. 101Alkanes are saturated carbons. What does this mean?They contain as many hydrogen atoms as possible in their molecules.
  102. 102The larger the hydrocarbon: -The ____ _____ it flows. -The _____ its boiling point. -The _____ volatile it is. -The ___ ____ it ignites.-Less easily it flows
    -Higher
    -Less
    -Less volatile
  103. 103How is crude oil separated into different fractions?Using fractional distillation
  104. 104Explain the process of the fractional distillation brieflyContinuously vaporising the mixtures and condensing the fractions at different temperatures
  105. 105What is a fractioning column?A tall tower that is hot at the bottom and gets cooler up the column.
  106. 106Why are different hydrocarbons collected at different levels of the fractional distillation column?Because different hydrocarbons have different boiling points so they condense at different levels
  107. 107In fractional distillation, hydrocarbons with the smallest molecules...Have the lowest boiling points and so are collected at the top of the column.
  108. 108Fractions with low boiling ranges...Have low viscosity so they are runny liquids. They are very flammable so they ignite easily. They also burn with clean flames producing little smoke so are very useful as fuels.
  109. 109What happens when your burn pure hydrocarbons completely?They are oxidised to carbon dioxide and water.
  110. 110What may happen if you burn hydrocarbons in a limited supply of air?Incomplete combustion may produce carbon monoxide. Carbon may also be produced and some of the hydrocarbons may not burn.
  111. 111What is produced by the incomplete combustion of hydrocarbons?Particles that contain soot (carbon) and unburnt hydrocarbons called particulates.
  112. 112What does sulfur dioxide and nitrogen oxides cause?Acid rain
  113. 113What is produced when fossil fuels containing sulfur compounds are burnt?Sulfur dioxide
  114. 114What do particulates cause?Global dimming because they reflect sunlight.
  115. 115Why are exhaust systems fitted with catalytic converters?To remove carbon monoxide and nitrogen oxides.
  116. 116What are biofuels?Fuels that are made from plant or animal products and are renewable.
  117. 117What are biodiesels?A fuel that can be made from vegetable oils extracted from plants.
  118. 118Examples of biofuels-Ethanol
    -Biodiesel
  119. 119What is ethanol?A biofuel made from sugar cane or sugar beet. It is a liquid and so it can be stored and distributed like other fuels and mixed with petrol.
  120. 120Advantages and disadvantages of using hydrogen as a fuel.-It produces only water when it's burned.
    -It is a gas so takes up a large volume which makes it difficult to store in the quantities needed for combustion in engines.
    -It can be produced from water by electrolysis but this requires large amounts of energy.
  121. 121How can large hydrocarbon molecules be broken down into smaller molecules?By cracking
  122. 122Explain the two ways in which cracking can be done-By heating a mixture of hydrocarbon vapours and steam to a very high temperature
    -By passing hydrocarbon vapours over a hot catalyst
  123. 123Different what are produced by crackingAlkanes and Alkenes
  124. 124Alkanes: -Are the carbon atoms in the chain linked by single carbon-carbon bonds or double? -Are they saturated or unsaturated?Single
    Saturated
  125. 125Alkenes: -Are the carbon atoms in the chain linked by single carbon-carbon bonds or double? -Are they saturated or unsaturated? -What is the general formula?Double
    Unsaturated
    C*n*H*2n*
    *(all after it is below the H)
  126. 126What colour change do you see when an alkene is present in bromine water?Orange to colourless
  127. 127What are plastics made from?Very large molecules called polymers.
  128. 128What are polymers?Large molecules made when many small molecules called monomers join together.
  129. 129What is the reaction to make a polymer called?Polymerisation
  130. 130Double bonds in the monomer become single bonds in the polymer when...The molecules have joined together
  131. 131What can alkenes be used to make?Polymers such as polyethene and polypropene
  132. 132Why can we make polymers from alkenes but not from alkanes?Alkenes are more reactive, are unsaturated, have a double bond
  133. 133What is a shape-memory polymer?Polymers that change back to their original shape when temperature or other conditions are changed. An example is a material used for stitching wounds that changes shape when heated to body temperature.
  134. 134Uses for polymersnew packaging materials
    waterproof coatings for fabrics
    fillings for teeth
    dressings for cuts
    hydrogels (for example for soft contact lenses and disposable nappy liners)
    smart materials (for example shape memory polymers for shrink-wrap packaging).
  135. 135What is an environmental problem with polymers?Many polymers are not biodegradable which means that plastic waste is not broken down when left in the environment. This is unsightly and can harm wildlife. Even when on landfill sites it takes up valuable space.
  136. 136What is good about biodegradable plastics?Microorganisms can break them down when they come into contact with soil.
  137. 137Why is it good to make plastics with cornstarch?Microorganisms break down the cornstarch so the plastic breaks down into very small pieces that can be mixed with soil or compost.
  138. 138How can you make biodegradable plastic?From plant materials such as cornstarch
  139. 139Which type of hydrocarbon is used for making polymers?Alkenes because they are unsaturated
  140. 140Explain the two ways in which ethanol can be made-By the fermentation of sugar from plants using enzymes in yeast. The enzymes in yeast cause the sugar to convert to ethanol and carbon dioxide.
    -By the hydration of ethene. Ethene is reacted with steam at a high temperature in the presence of a catalyst. The ethene is obtained from crude oil by cracking.
  141. 141Fermentation: -What temperature is it done at? -What can it only produce? -How do you get pure ethanol?-Room temperature
    -A dilute aqueous solution of ethanol
    -The ethanol must be separated from the solution through fractional distillation
  142. 142What are the advantages and drawbacks of producing ethanol through ethene?The reaction can be run continuously and produces pure ethanol but requires a high temperature and crude oil is not renewable.
  143. 143What is the word equation for the fermentation of sugar using yeast?Sugar /glucose -> ethanol + carbon dioxide
  144. 144What is the word equation for the hydration of ethene?Ethene + steam -> ethanol
  145. 145How can vegetables oils be extracted from plants, seeds, nuts and fruits?-By crushing and pressing the plant material followed by removing water and other impurities.
    -By distilling the plant material mixed with water which produces a mixture of oil and water from which the oil can be separated.
  146. 146Why are vegetable oils important foods?-They provide us with a lot of energy and important nutrients
    -They release a lot of energy when they burn in air and so can be used as fuels.
    -They are used to make biofuels such as biodiesel
  147. 147What is it called when they are several double bonds in each molecule?Polyunsaturated
  148. 148Vegetable oils contain _____ carbon-carbon bonds, so they are ______.Double
    Unsaturated
  149. 149Why are vegetable oils used instead of water in cooking?-Their boiling point is higher so food is cooked at a higher temperature and therefore cooked quicker
    -It changes the flavour, colour and texture of the food
    -It increases the energy content of the food
  150. 150How can vegetable oils be hardened?By reacting them with hydrogen at 60 degrees Celsius with a nickel catalyst. This makes them solids at room temperature that are suitable for spreading. It removes the double carbon-carbon bonds to produce a saturated fat. This is called hydrogenation.
  151. 151Why do hydrogenated oils have a higher melting point?Because they are more saturated
  152. 152Oils do not dissolve in water but oils and water can be used to produce...Emulsions
  153. 153Describe and give examples of emulsions-They are opaque and thicker than oil and water they are made from
    -Milk, cream, salad dressings and ice creams, some water-based paints and cosmetic creams
  154. 154What are emulsifiers?Substances that help stop the oil and water from separating into layers. Most emulsions contain emulsifiers to keep the emulsion state.
  155. 155How does an emulsifier work?They have a small hydrophilic part and a long hydrophobic part. The hydrophilic part is attracted to water and the hydrophobic part is attracted to oil. The hydrophobic parts of many emulsifier molecules go into each oil droplet so the droplets become surrounded by hydrophilic parts which keeps the droplets apart in water preventing them from joining and separating out.
  156. 156Benefits and drawbacks of using vegetable oils in food.-They are high in energy and contain important nutrients and contain unsaturated fats which are believed to be better for your health than saturated fats.
    -High in energy so easy to eat too much
  157. 157Why should you be aware of emulsifiers in the food you eat?Because they taste better, it is less obvious that they are high in fat and you may be tempted to eat more.
  158. 158What layers is the earth made up of and describe them?-Inner Core
    -Outer Core (Liquid outer part, solid inner part)
    -Mantle (solid but parts can flow very slowly, thick)
    -Crust (thin, solid)
    -Atmosphere (surrounds the earth)
  159. 159Where do the earth's limited resources come from?Its crust, the oceans and the atmosphere
  160. 160What are tectonic plates?The Earth's crust and upper part of the mantle is cracked in massive pieces. These are tectonic plates.
  161. 161What causes tectonic plates to move?They move a few centimetres each year because of convection currents.
  162. 162What are convection currents caused by?By energy released by the decay of radioactive elements heating up the mantle.
  163. 163How do earthquakes and volcanoes form?Where the plates meet, huge forces build up. Eventually the rocks give way, changing shape or moving suddenly and causing earthquakes, volcanoes or mountains to form.
  164. 164Why can scientists not predict when and where earthquakes will happen?We do not know enough about what is happening inside the earth and we do not have good enough data or models to make accurate predictions.
  165. 165What idea did Alfred Wegener put forward and why were his ideas not accepted for many years?Continental drift the idea that the Earth's continents were once joined together, but gradually moved apart over millions of years
  166. 166What did scientists think before Wegener's theory?The Earth was shrinking as it cooled. If the idea was correct, however, mountains would be spread evenly over the Earth's surface.
  167. 167What evidence is there for Wegener's theory?the same types of fossilised animals and plants are found in South America and Africa
    the shape of the east coast of South America fits the west coast of Africa, like pieces in a jigsaw puzzle
    matching rock formations and mountain chains are found in South America and Africa
  168. 168Why were Wegener's ideas not accepted for many years?He could not explain why the continents moved and they had their own/different/established ideas about the earth
  169. 169What happens during a convection current in the earth?-Hot molten rock rises to the surface. creating new crust.
    -The older, cooler crust, then sinks down where the convection current starts to fall
    -The land masses on these plates move slowly
  170. 170What was believed to cover the earth at first and what did these release?Volcanoes
    Carbon dioxide, water vapour and nitrogen
  171. 171What did the earth's early atmosphere mainly consist of?Mainly carbon dioxide
    May have also been water vapour with traces of methane and ammonia
  172. 172As the earth cooled, what happened to most of the water vapour?It condensed to form oceans.
  173. 173What happened as plants spread over the earth?The amount of carbon dioxide in the atmosphere decreased and the amount of oxygen increased because of photosynthesis
  174. 174How did the Miller-Urey experiment test one possible theory for how life began?They mixed together the chemicals thought to be present in the earth's early atmosphere-water, methane, ammonia and hydrogen and used a high voltage spark to stimulate lightning and provide energy.
  175. 175What was the outcome of the Miller-Urey experiment?After a week they found that amino acids, the building blocks for proteins, had been produced.
  176. 176What theory does the Miller-Urey experiment support?Primordial Soup Theory
  177. 177What is the primordial soup theory?The idea that complex chemicals needed for living things to develop could be produced naturally on the early Earth.
  178. 178What happened to most of the carbon dioxide in the earth's early atmosphere?Plants took it up and animals ate the plants where much of the carbon dioxide ended up in plant and animal remains as sedimentary rocks and fossil fuels. Carbon dioxide dissolves in the oceans and some probably formed insoluble carbonate compounds that were deposited on the seabed and became sedimentary rocks.
  179. 179How was limestone formed?From the shells and skeletons of marine organisms.
  180. 180What gases are in the earth's atmosphere and what percentage are they all?Nitrogen 78%, Oxygen 21%, Carbon Dioxide 0.04%, Argon 0.9%
  181. 181How can the main gases in the air be separated?By fractional distillation
  182. 182How does fractional distillation work?The air is cooled to below -200 degrees Celsius and fed into a fractional distillation column. Nitrogen is then separated from oxygen and argon and further distillation is used to produce pure oxygen and argon.
  183. 183Why can the gases in air be separated by fractional distillation?Because it is a mixture of different substances that have different boiling points.
  184. 184What are the boiling points of nitrogen and oxygen?oxygen liquefies at –183ºC
    nitrogen liquefies at –196ºC.
  185. 185Name processes that remove carbon dioxide from the atmosphereDissolves in water particularly oceans
    Photosynthesis
  186. 186Why is the level of carbon dioxide in the atmosphere today increasing?-Volcanic activity-geological activity moves carbonate rocks deep into the earth and during volcanic activity they may release carbon dioxide back into the atmosphere.
    -Burning fossil fuels-Burning carbon which has been locking up in fossil fuels for millions of years releases carbon dioxide into the atmosphere

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GCSE Chemistry FlashCards sobre C1, criado por ruthkeat em 01-03-2016.
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