C2 Chemical Resources Flashcards
Describe the structure of the Earth
A sphere with a thin rocky crust, a mantle and an iron core
The movements of tectonic plates can cause … (2)
Volcanic activity
Earthquake
Approximate movement of tectonic plates every year
2.5cm
Many theories have been put forward to explain the nature of Earth’s surface, scientists accept the theory of plate tectonics
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Explain how the size of crystals in an igneous rock is related to the rate of cooling of the rock
Igneous rocks contain crystals. These form as the molten rock solidifies. They lock together randomly to form the solid rock. The more slowly the molten rock cools, the larger the crystals become.
Describe magma
The molten rock beneath the surface of the Earth
Describe lava
The molten rock at the Earth’s surface
Explain why some people chose to live near volcanoes
Volcanic soil is very fertile. It is rich in minerals that plants need to grow well.
Describe the lithosphere
Relatively cold rigid outer part of the Earth that includes the crust and a part of the mantle. They are made of the tectonic plates, hence they are less dense than the mantle below
Explain problems associated with studying the structure of the Earth
- Crust is to thick to drill through
- the need to use seismic waves produced by earthquakes or man made explosions
Explain why g theory of tectonic plates is widely accepted now. (2)
- It explains a wide range of evidence
- It has been discussed and tested by a range of scientists
Describe the mantle
- Zone between the crust and the core
- Cold and rigid just below the crust
- Hot and non-rigid at greater depths and therefore able to move
Describe the theory of tectonic plates
- Energy transferring involving convention currents in the semi-rigid mantle causing the plates to move
- Oceanic plate is more denser than the continental plate
- Collision between oceanic plate and continental plate leads to subduction and partial melting
- Plates cooler at ocean margins so sink and pull plates down
Describe in simple terms the development of Wegener’s theory of tectonic plates (4)
- theory first put forward in 1914
- theory rejected and not accepted by scientists
- new evidence in 1960s ( sea floor spreading)
- slowly accepted by scientists due to new research and evidence
Describe different types of igneous rocks that are formed from lava
- Iron rich basalt is formed from runny lava from fairly safe volcanic eruption
- silica rich rhyolite is formed from thick lava from an explosive eruption
Explain why geologists study volcanoes (2)
- to be able to predict future eruptions
- to reveal information about the Earth’s structure
Name rocks used in construction of buildings and roads
Granite
Limestone
Marble and aggregates
Explain the environmental problems with carrying out Quarrying or mining. (2)
- landscape destroyed and has to be reconstructed once the mining or quarrying is over
- increased noise, dust and traffic
What are limestones and marble forms of?
Calcium Carbonate
What are the products of the thermal decomposition of limestone?
Calcium oxide and Carbon dioxide
Describe how concrete is made
- Cement, sand , aggregate and water are mixed together
- Mixture is then allowed to settle
Describe how concrete can be reinforced using steel support
Concrete can be strengthened by allowing it to set around a supporting mesh of solid steel
What type of rocks are limestone, marble and granite. Explain why they have different relative hardness?
- Limestone is a sedimentary rock formed from the shells and skeletons of sea creatures
- Marble is a metamorphic rock made by the action of high pressure and temperatures on limestone
- Granite is an igneous rock.
( Limestone, Marble, Granite) —–> Granite is the strongest because its crystals are joins together more strongly than the grains in marble
Describe thermal decomposition
When a product is heated and the single substance is chemically broken down into 2 new substances
How is cement made?
Limestone and clay are heated togther
Why is reinforced concrete a useful material?
Hardness of concrete
Flexibility and strength of the steel
How is copper extracted from malachite and carbon
By heating it
How can copper be purified?
By electrolysis
Explain why recycling copper is cheaper than extracting copper from its core
- saves resources
- use of less energy
How is copper metal removed from it core?
Copper metal is extracted by heating crushed ore with carbon
What is an alloy?
Mixture containing 2 or more metal elements
List some alloys
Brass Bronze Solder Amalgam Steel
What are some of the uses of alloys?
Amalgam can be used for tooth fillings
Solder can be used to join electrical wires
Brass can be used for musical instruments or coins
Describe the use of electrolysis in the purification of copper
- Cathode is the pure copper
- Anode is the impure copper
- copper (II) Sulfate solution is the electrolyte
- cathode gains mass because copper is deposited
- anode loses mass as copper dissolves
- A redox reaction
Main metals in each alloy
Amalgam - mercury
Solder - tin and lead
Brass - copper and zinc
Describe nitinol and its uses
Nitinol (nickel and titanium) used to make spectacle frames as the frames which will return to their original shape after bending
What conditions are required by rusting
Iron
Water
Oxygen
What metal doesn’t corrode in moist conditions? Why is this so?
Aluminium, this is because it is protected by a thin layer of aluminium oxide. It prevents air and oxygen reaching the metal
Compare the properties of aluminium and iron
Iron is more denser Aluminium doesn't corrode Iron is magnetic Both are malleable Both are good electrical conductors
What major materials are required to build a car
Steel, copper and aluminium
Plastic , fibres, glass
Describe the advantages of recycling materials
Saves natural resources
Reduces disposal problems
Comparison between iron and steel
Steel is stronger and stronger
Steel is less likely to corrode
Describe advantages and disadvantages of making the car body with steel or aluminium
- Car body of the same size will be lighter with aluminium being used
- Car body with aluminium will corrode less
- Car body with aluminium will be more expensive
Why are new laws introduced specifying that a minimum percentage of the car must be recyclable
- reduces problem of disposing
- saves natural resources
Haber process produces ammonia, where do the reactants come from
Nitrogen comes from the atmosphere
Hydrogen comes from cracking of oil fractions or from natural gas
Describe the cost of making a new substance depends on which factors (5)
Price of energy Wage Equipment Cost of raw materials Cost of catalyst How quickly the new substance is made
Uses of ammonia
Manufacture of fertilisers
Manufacture of nitric acid
Describe how ammonia is made during the Haber Process
Iron catalyst
High pressure
Temperature in the region of 450’C
Unreacted nitrogen and hydrogen are recycled
Explain the conditions used in the Haber process
High pressure increases the percentage yield of ammonia
High temperature decreases the percentage yield of ammonia
High temperature gives a high rate of reaction
450’C is an optimum temperature to give high rate of reaction with a sufficiently high percentage yield of ammonia
Catalyst increases rate of reaction
Describe how different factors affect the cost of making a new substance
The higher the pressure, the higher the plant cost
The higher the temperature, the higher the plant cost
Catalyst reduce cost by increasing the rate of reaction
When unreacted starting materials are recycled costs are reduced
Automation reduces the wage bills
Explain how the economic considerations determine the conditions used
- Rate must be high enough to give a sufficient daily yield of product
- Percentage yield must be high enough to give a sufficient daily yield of product
- A low percentage yield can be accepted if the reaction can be repeated many times with recycled starting materials
- Optimum conditions used that give the lowest cost rather than the fastest reaction or highest percentage yield
Describe how universal indicator can be used to describe
Universal indicators is a mixture of different indicators. Each one changes colour over a different pH range. This means that the pH of a solution can be estimated using a Universal indicator
Alkali is a soluble base
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An acid can be neutralised by an alkali or base, or vice versa
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Acid + Base —-> Salt + Water
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All acids contain H+ ions
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The pH of a solution is determined by the concentration of H+ ions
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Alkalis contain OH- ions
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Metal oxide + acid —-> salt + water
Metal hydroxide + acid —-> salt + water
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Carbonate + acid —-> salt + water + carbon dioxide
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Fertilisers increases crop yield
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Plants absorb minerals from their roots
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Describe fertilisers
Fertilisers are chemicals that provide plants the essential chemical elements such as nitrogen, phosphorus and potassium
What are the 3 essential elements required by plants to grow
Phosphorous
Potassium
Nitrogen
What are the advantages and disadvantages of using fertilisers
- Increasing food supply
- Eutrophication
What apparatus is required to prepare a fertiliser?
- Burette and measuring cylinder
- Filter funnel
Names of nitrogenous fertilisers manufactured from ammonia
Ammonium nitrate
Ammonium Phosphate
Ammonium Sulfate
Urea
Explain why fertilisers must be dissolved in water before they can be absorbed by plants
Minerals are taken up by the roots, roots can not absorb insoluble minerals.
Arguments against and for the use of fertilisers
- World population is rising so more food needs to be produced
- Eutrophication and pollution of water supplies can be caused due to the over use of fertilisers
Explain how the use of fertilisers increases crop yield
- replaces essential elements used by a previous crop or provides extra essential elements
- more nitrogen gets incorporated in to plant protein so increased growth
Explain the process of eutrophication
- run off of fertiliser
- increase of nitrate and phosphate in water
- algal bloom
- blocks of sunlight to other plants which die
- aerobic bacteria use up the oxygen
- many living organisms die
Sodium chloride can be obtained from the sea or from salt deposits
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What are the products of electrolysis of concentrated sodium chloride
Hydrogen and chlorine
What is the chemical test for chlorine
Bleaches moist litmus paper from blue to red and then white
Uses of sodium chloride
Used as a preservative
Used as a flavouring
Household bleach, PVC and solvents are made from substances derived from salt
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Chlorine can be used to sterilise water and to make solvents, household bleaches and plastics
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Hydrogen is used in the process of manufacturing margarine
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Sodium hydroxide is used to make a soap
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What is solution mining ?
Water is pumped from the surface into the deposit deep underground. The sodium chloride dissolves in the water, and the brine is pumped up to the surface. This is a continuous process that needs little labour, which keeps costs down.
How can mining for salt lead to subsidence
This is where the land slumps downwards because of a mine below, leading to cracked buildings and holes appearing on the ground
Products of electrolysis of sodium chloride
Chlorine is made at the anode
Hydrogen is made at the cathode
Sodium hydroxide is also made, this stays dissolved
