C2 Flashcards
Describe the structure of the Earth
The Earth has a layered structure made up of the core, mantle and crust. The crust and upper part of the mantle is broken into large pieces called tectonic plates. These move slowly over the mantle.
Explain how seismic waves are used to study the Earth’s structure.
S-waves can travel through the mantle, which shows that it’s solid. S-waves can only travel through solids. S-waves not detected in outer core’s shadow, suggesting is is liquid. - P-waves travel faster through the middle of the core, suggesting the inner core is solid.
Describe the different between runny and thick lava.
Different types of igneous rocks form lava (molten rock on the Earth’s surface): basalt is rich in iron - it formed from runny lava produced in a fairly safe volcanic eruption, rhyolite is rich in silica - it formed from thick lava produced in an explosive eruption.
Explain why geologists study volcanoes.
Geologists study volcanoes to try to predict future eruptions, and to gather information about the Earth’s structure.
Name the main construction materials to substances found in the Earth’s crust
Granite, limestone and marble are used as construction materials. Cement, which is made from limestone, is used to make concrete. However reinforced concrete has better properties for construction work than concrete alone.
Compare hardness of limestone, marble and granite.
Granite is much harder than marble, which is much harder than limestone.
What is a balanced symbol equations to describe the thermal decomposition of limestone?
calcium carbonate –> calcium oxide + carbon dioxide CaCO3 –> CaO + CO2 copper(II) carbonate –> copper(II) oxide + carbon dioxide CuCO3 –> CuO + CO2
How is cement made?
Cement and concrete are made from limestone, cement is made by heating powdered limestone with clay, concrete is made by mixing cement with sand, water and aggregate (crushed rock). Chemical reactions happen in the mixtures and eventually they set hard.
What equipment is needed for electrolysis?
See Diagram below.
Explain the advantages of recycling copper.
The world is running out of ores that are rich in copper.The recycling of copper is cheaper, and uses less energy and resources than extracting fresh copper from its ores.
Name the main metals in amalgams, brass and solder
amalgam - mercury, brass - copper and zinc, solder - lead and tin.
Define an alloy.
An alloy is a mixture of two elements, one of which is a metal. Alloys often have more useful properties than the metals they contain.
How does salt water and acid rain affect rusting.
Iron and steel rust when they come into contact with water and oxygen. They rust faster in salty water or acid rain. Aluminium, on the other hand, does not corrode easily, because its surface is protected by a layer of aluminium oxide.
Describe how rusting happens.
Iron and steel rust when they come into contact with water and oxygen. Both water and oxygen are needed for rusting to occur. In the experiment below, the nail does not rust when air or water is not present. Remember that 21 per cent of the air is oxygen. Rusting is an oxidation reaction. The iron reacts with water and oxygen to form hydrated iron(III) oxide, which we see as rust.
Explain why aluminium does not corrode
Unlike iron and steel, aluminium does not rust or corrode in moist conditions. Its surface is protected by a natural layer of aluminium oxide. This prevents the metal below from coming into contact with air and oxygen. The layer of aluminium oxide does not flake off, unlike rust which can flake off the surface of iron and steel objects.
Describe advantages and disadvantages of building cars from aluminium and steel
Aluminium has some advantages over steel. Since it has a lower density than iron or steel, a car body made from aluminium will be lighter than the same car body made from steel. This results in improved fuel economy. Also, aluminium does not corrode easily, so a car body made from aluminium will corrode less than one made from steel. It should last longer as a result. However, aluminium is more expensive than steel. So a car made from aluminium is likely to be more expensive than one made from steel.
Describe the conditions needed to make ammonia in the Haber process and construct the balanced symbol equation.
The raw materials for this process are hydrogen and nitrogen: hydrogen is obtained by reacting natural gas with steam, or from cracking oil fractions, nitrogen is obtained from the air. In the Haber process, nitrogen and hydrogen react together under these conditions: a high temperature - about 450ºC a high pressure an iron catalyst.
Describe neutralisation and recall the word equation.
When an alkali is added to an acid the pH of the mixture rises. This is because the alkali reacts with the acid to form neutral products. The reverse situation also happens too: when an acid is added to an alkali the pH of the mixture falls. This is because the acid reacts with the alkali to form neutral products. A reaction in which acidity or alkalinity is removed is called neutralisation. A neutralisation involving an acid and a base (or alkali) always produces salt and water. acid + base –> a salt + water
Explain how metal oxides and hydroxides, and carbonates react with acid, and construct word equations.
Carbonates also neutralise acids. As well as a salt and water, carbon dioxide is also produced. The name of the salt can be predicted in just the same way. For example: hydrochloric acid + potassium carbonate –> potassium chloride + water + carbon dioxide
Predict the names of salts from laboratory acids
The name of the salt produced in a neutralisation reaction can be predicted. The first part of the name is ‘ammonium’ if the base used is ammonia. Otherwise, it is the name of the metal in the base. The second part of the name comes from the acid used: chloride, if hydrochloric acid is used, nitrate, if nitric acid is used, sulfate, if sulfuric acid is used, phosphate, if phosphoric acid is used.
Explain why fertilisers need to be soluble to be absorbed by plants
Fertilisers make crops grow faster and bigger so that crop yields are increased. They are water-soluble minerals. They must be able to dissolve in water so that plants can absorb them through their roots.
Identify arguments for and against using fertilisers
The world population is increasing all the time, so more food has to be produced. Without fertilisers the yields of crops would be reduced. However, if too much fertiliser is used it can pollute water supplies. It may also lead to eutrophication, a situation where there is not enough oxygen dissolved in the water for aquatic organisms to survive.
Predict the names of the acids and alkalis needed to make different fertilisers
Most fertilisers are made by the reaction of an acid and an alkali. The table shows some examples.
Describe how salt can be mined as rock salt if extracted by solution mining
Salt can also be mined by solution mining. This happens in Cheshire in the North West of England. Water is pumped underground and into the salt deposit. Salt dissolves in the water, forming a concentrated salt solution. This is then pumped up to the surface ready for use by the chemical industry. Solution mining is a continuous process that is safer than sending miners underground.
