Revision Flashcards
What gases are believed to have been released from volcanoes during the first billion years of the Earth’s existence?
Nitrogen, carbon dioxide, water vapour; small amounts of ammonia and methane.
How did the oceans form?
Water vapour in the atmosphere condensed.
Why did the amount of carbon dioxide in the earlier atmosphere decrease?
When oceans formed, carbon dioxide dissolved in the water; carbonates precipitated producing sediments, reducing carbon dioxide in the atmosphere.
How do you test for oxygen gas?
Glowing splint delights
What organisms increased the amount of oxygen in the Earth’s atmosphere?
Primitive plants/ algae.
Write the balanced symbol equation for photosynthesis.
6CO2 + 6H2O ——————> C6H12O6 + 6O2
Other than photosynthesis, what other factors decreased the level of carbon dioxide in the atmosphere?
Formation of sedimentary rocks and fossil fuels (natural gas, oil, coal).
Describe the main changes to the atmosphere over time and the likely causes of these changes.
Intense volcanic activity – water vapour, carbon dioxide, nitrogen, ammonia, methane released.
Water vapour condensed to form oceans.
Atmosphere mostly carbon dioxide; nitrogen slowly building up over time.
Carbon dioxide dissolved in oceans; carbonates precipitated producing sediments. Carbon dioxide levels in atmosphere drop.
Photosynthesis – algae produce oxygen.
Plants evolved, levels of carbon dioxide reduced, levels of oxygen increased; animals evolved.
Carbon dioxide levels dropped during the formation of sedimentary rock (from sediments) and fossil fuels (from organisms).
Name 3 greenhouse gases.
Water vapour, carbon dioxide, methane.
What is the link between greenhouse gases and the temperature of the Earth?
Greenhouse gases maintain temperatures on the Earth high enough to support life.
Name human activities which increase the amount of carbon dioxide in the atmosphere.
Burning/ combustion of fossil fuels, deforestation.
Name human activities that increase the amount of methane in the atmosphere.
Farming of livestock; landfill sites.
What do many scientists believe about human activities and the temperature of the Earth’s atmosphere?
Human activities will cause the temperature of the Earth’s atmosphere to increase at the surface resulting in climate change.
Why are there issues surrounding modelling human impact on climate change?
It is difficult to model these changes
There are uncertainties caused by the location where the measurements are taken.
Questions regarding historical accuracy.
Name two gases and their compositions in today’s atmosphere.
Nitrogen (80%), Oxygen (20%)
Place these metals in order of their reactivity:
Potassium, silver, copper, magnesium
Highest: Potassium, magnesium, copper, silver: lowest
Name the two non-metals in the reactivity series.
Carbon and hydrogen
Metals form positive ions. What is the scientific name for these positive ions?
Cations
Why is gold found in the Earth as an element rather than a compound?
It is very unreactive.
What is a redox reaction?
Reaction involving both oxidation and reduction.
Describe oxidation in terms of electrons.
oxidation is loss of electrons.
Describe reduction in terms of electrons.
reduction is gain of electrons.
What is an ore?
Metal compound in a rock.
What is produced when metals react with oxygen?
Metal oxide.
What is this process called and why?
Oxidation, gain of oxygen.
What is reduction in terms of oxygen?
Loss of oxygen
What type of ions do metals produce?
Positive
Which is more reactive, potassium or iron?
Potassium
Which two non-metals can be included in the reactivity series?
Carbon and hydrogen
Why is gold found as an element in the Earth?
Unreactive metal
How are metals, less reactive than carbon, extracted from their ores?
Reduction with carbon
Describe oxidation in terms of electrons.
OIL – loss of electrons
Describe reduction in terms of electrons.
RIG – gain of electrons
Write the word equation for the reaction between lithium and water.
lithium + water → lithium hydroxide + hydrogen
Write the balanced symbol equation for the reaction between lithium and water.
2Li(s) + 2H2O(l) → 2LiOH(aq) + H2(g)
HT: Zinc can be extracted from zinc oxide by heating it with carbon in the blast furnace. Carbon monoxide is also produced. Which reactant is:
a) Oxidised? Carbon
b) Reduced? Zinc oxide
Why is electrolysis used to extract aluminium from its ore?
Aluminium is more reactive than carbon.
Why is electrolysis an expensive way to extract metal from its ore?
Large amounts of energy needed.
Name the compound from which aluminium is extracted.
Aluminium oxide/ bauxite.
What type of ores can phytomining and bioleaching be used on?
Low-grade ores
Why are phytomining and bioleaching used?
Avoids traditional mining methods of
digging, moving and disposing of large amounts of rock
How does phytomining extract metals?
Uses plants to absorb metal compounds,
the plants are harvested and burned,
this produces ash that contains metal compounds.
What is a life-cycle assessment?
Considering the impact on the environment for a product; in the lifetime of the product.
Life cycle assessments are carried out to assess the environmental impact. What stages of a product are covered?
Obtaining the raw materials
Manufacturing the product
Using the product
Disposal of the product.
What areas of life cycle assessments can be easily quantified?
Use of water, resources, energy and waste production.
How can metals be recycled?
Melting, recasting or reforming.
What are three advantages of recycling metals?
Cheaper, reduced environmental impact, avoids need for mining.
Where are most metals found in the periodic table?
Transition metals between Groups 2 and 3
Name four properties of transition metals.
High melting point, high density, form coloured compounds, act as catalysts.
What is corrosion?
Oxidation of metals.
Name three ways to prevent the rusting of iron.
Exclusion of oxygen, exclusion of water, sacrificial protection.
What is electroplating? What is it used for?
Using electricity to oat a metal with a thin layer of another metal.
What is an alloy?
Metal mixed with other elements.
How does converting a metal to an alloy improve the strength?
Distorts the layers in the structure making it difficult for them to slide over each other.
What is magnalium?
Alloy of aluminium and magnesium.
Name two uses of magnalium.
Aircraft/ car parts, pyrotechnics.
How is iron turned into steel?
Addition of carbon and other substances e.g. chromium.
