to reduce the melting temperature, making it cheaper
Why is sodium carbonate used in the manufacture of glass?
concrete structures are commonly viewed as unattractive
What is the disadvantage of concrete as a building material?
iron oxide
What compound do iron ores (e.g. haematite) contain?
alloys which return to their original shape after being bent
What are smart alloys?
they have a double bond
Why can alkenes act as monomers?
treated with powdered limestone to form calcium sulfate
How can sulfur dioxide be removed from waste gases after the combustion of fuel?
allows coke to burn
What is the function of air in the blast furnace?
for artificial hip joints
How is titanium used in medicine?
the movement of tectonic plates that allow continents to shift apart
What is continental drift?
similar fossils on both sides of the Atlantic
What is the main piece of evidence for Wegener's theory?
21%
What percentage of the Earth's atmosphere is oxygen?
it becomes colourless
What happens when bromine water is shaken with an alkene?
the substance is licensed by the EU
What does an E number indicate?
solid
At room temperature, what state is a large hydrocarbon?
may permanently disfigure the local environment, creates noise and heavy traffic
What are two disadvantages of the limestone industry?
reacts with carbon dioxide in rainwater and slowly wears away
What is the disadvantage of limestone as a building material?
ores which contain little of the desired metal element and a lot of waste rock
What is meant by
separating a pure liquid from a mixture of liquids
What is distillation used for?
CnH2n+2
What is the general formula of an alkane?
to stop the glass dissolving in water
Why is limestone used in the manufacture of glass?
it does not react with water
Why is copper useful for plumbing?
they have a thin layer of their oxides on their surface, which stops water and air getting to the
metal
Why are aluminium and titanium resistant to corrosion?
from the gases given out by volcanoes
How was the Earth's early atmosphere formed?
tiny particles that are released during combustion
What is the cause of global dimming?
light bulbs
What is argon used for?
the plant material is squeezed and crushed
How is oil obtained from plant material?
food crops should be used only to feed hungry people
Why do people say it is unethical to use biodiesel?
requires a lot of energy
Why is aluminium extraction expensive?
less energy is needed to produce recycled aluminium than to extract aluminium from its ore
Why is aluminium extensively recycled?
fatty acids and glycerol
What do molecules of vegetable oils contain?
fermentation
How is sugar from plant material converted into ethanol and carbon dioxide?
substances that let polymer molecules slide over each other more easily
What are plasticisers?
increased coastal erosion and flooding of low-lying land
What will happen as a result of melting polar ice caps?
rocks that contain metal or metal compounds in sufficient amounts to make it economically
worthwile extracting them
What is an ore?
they contain trans fats
Why are partially hydrogenated vegetable oils unhealthy?
using limestone - it turns cloudy white when carbon dioxide is bubbled through it
How can we test for carbon dioxide after the thermal decomposition of a metal carbonate?
reduction
What is the name for reactions in which oxygen is removed?
by blowing oxygen into the molten metal, forming carbon monoxide and carbon dioxide
How is carbon removed from pure iron?
alloy
What is the name for a mixture of two or more elements, where at least one element is a metal?
combustion
Name the alternative word for 'burning in air'
useful for making things such as glass and concrete, provides employment opportunities
Wht are two advantages of the limestone industry?
it is easily formed into different shapes before it sets hard
What is an advantage of concrete as a building material?
lets lots of light in
What is an advantage of glass as a building material?
they are chemically unreactive
What is the main property of noble gases?
water + carbon dioxide
What are the products of complete combustion?
thermal decomposition
How is quicklime produced from limestone?
it was difficult to work out what the mechanism was that could make the plates move
Why did it take more than 50 years for Wegener's theory to be accepted?
laser eye surgery
What is krypton used for?
when large hydrocarbon molecules are broken down into smaller hydrocarbon molecules, by
being passed over a hot catalyst
What is cracking?
unsaturated
Are alkenes saturated or unsaturated hydrocarbons?
their double bonds allow them to react with oxygen
Why can alkenes be used as fuels?
saturated
Are alkanes saturated or unsaturated?
less sunlight reaching the Earth's surface
What is the effect of global dimming?
burns in air to produce heat, and reacts to form carbon monoxide - needed to reduce the iron
oxide
What is the function of coke in the blast furnace?
good conductors/easily bent/high densities/high melting points
What are some properties of transition metals?
as much carbon dioxide is released as produced
What is meant by the term 'carbon neutral'?
gas
At room temperature, what state is a small hydrocarbon?
water + carbon monoxide + carbon
What are the products of incomplete combustion?
thermal decomposition + water
How is slaked lime made from limestone?
a nickel catalyst
What can be used to speed up hydrogenation?
heating-evaporation-cooling-condensation
What is the sequence of events in distillation?
buildings with lots of glass can be too hot in the summer
What is a disadvantage of glass as a building material?
reaction with carbon or carbon monoxide
How are the reasonably reactive metals extracted from their ores?
helps to remove acidic impurities from the iron by reacting with them to form molten slag
What is the function of limestone in the blast furnace?
photosynthesis, locked up in rocks, dissolved in oceans
Why did the carbon dioxide levels in the Earth's atmosphere fall?
it absorbs heat energy and prevents it from escaping from the Earth's surface into space
What is the role of carbon dioxide in the greenhouse effect?
convection currents in the mantle - caused by heat produced by the decay of radioactive
elements
What causes tectonic plates to move?
nitrogen - 78%
What is the main gas in the Earth's atmosphere, and what percentage?
calcium oxide + carbon dioxide
What are the products of the thermal decomposition of calcium carbonate?
electrolysis
How are the most reactive metals extracted from their ores?
resistant to corrosion
What is a property of stainless steel?
the process involves several stages
Why is titanium extraction expensive?
using bromine or iodine
How can carbon-carbon double bonds be tested for in unsaturated oils?
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