C1.26a The effects of acid rain You are going to demonstrate some of the effects of acid rain. Carry out the following tests and answer the questions that follow.
Apparatus 2 × small beakers
2 × test tubes
2 × Petri dishes and lids
cotton wool
marble chips
iron filings
cress seeds
‘acid rain’
eye protection
Health and safety ●
Wear eye protection
Method Acid rain and buildings Many buildings are constructed from limestone, marble or concrete – all of which contain calcium carbonate. A Put a few pieces of marble in each of two beakers. B Cover the pieces in one beaker with water and those in the other beaker with ‘acid rain’.
Acid rain and metals Metals are used for many purposes. Iron, in the form of steel, is one of the most commonly used metals. A Put some iron filings in each of two test tubes. B Cover the iron filings in one test tube with water and those in the other test tube with ‘acid rain’.
Acid rain and plants A Put pieces of cotton wool in each of two Petri dishes. B Moisten one with water, and the other with ‘acid rain’. C Sprinkle cress seeds into both Petri dishes and put a cover on the dishes. D Leave the dishes in a warm place for a few days. Make sure the cotton wool is kept moist.
Results 1
Describe what happened in each of the tests.
2
The ‘acid rain’ you used is more concentrated than even the most polluted rainfall. Explain how using a more concentrated acid could have affected each of your results.
3
Write a report comparing the possible effects of acid rain on buildings, metals and plants.
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C1.26b Investigating a pollution problem The first evidence that there was a severe pollution problem in Norway came in the 1970s from observations that there were fewer fish in lakes. An initial investigation discovered that the lakes and rivers in these areas were more acidic than usual. So scientists asked themselves the question 'What is causing the acidity in the water?' When scientists are trying to find the answer to a question like this, they suggest hypotheses. A hypothesis is a possible answer to a question, and it can be tested. If the results of many tests support a hypothesis, the hypothesis becomes a theory. The cards below show some of the hypotheses that scientists suggested to explain how the acidification was occurring. Your task is to design an investigation to test each of these hypotheses. For each investigation: ●
describe and explain what you would do
●
say how you would make your investigation fair
●
say what you would expect to find if the hypothesis is correct.
Hypotheses
A
The acidic waters are the cause of loss of fish
B
Acid rain made the lakes and rivers acidic
C
Sulfur dioxide in the air causes acid rain
D
Sulfur dioxide is being put into the air by power stations and vehicles
E
Norway does not produce enough sulfur dioxide to explain the effects seen, so it could be coming from somewhere else
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C1.26c Acid rain questions Name 1
2
Class
Date
These statements describe how acid rain occurs. Write numbers in the boxes to put them in the correct order.
The acidic clouds can be transported by the wind from other countries.
Sulfur forms sulfur dioxide when it burns.
Some fuels contain sulfur.
Acid rain falls from the clouds.
The sulfur dioxide dissolves in water droplets in the air and forms an acidic solution.
Write a word equation to show how sulfur dioxide forms when sulfur is burnt. ______________________________________________________________________________
3
a
Write down three problems caused by acid rain. ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________
b
'Scrubbers' can be fitted to the chimneys of power stations to remove the sulfur dioxide in the waste gases. Write down one advantage and one disadvantage of this technology. Advantage Disadvantage
4
The speech bubble shows one person’s opinion about acid rain. It costs money to remove sulfur from fuel. Why should we bother? There isn't much of a problem with acid rain in the UK.
What would you say to this person? ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________
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C1.26d Low-sulfur fuels Fuels obtained from crude oil normally contain some sulfur. Low-sulfur fuels have been available in the UK since about 1997, but these fuels cost 2 to 3 pence per litre more to produce than 'normal' fuel. The cost of fuel sold at filling stations in the UK includes government tax. The tax on ultra-low sulfur diesel (ULSD) fuel was reduced in 1997, and most users of diesel fuel switched to it. In 2000, the government reduced the tax on ultra-low sulfur petrol (ULSP) by 2 p per litre, and reduced the tax on ULSD even further. At that time, less than 10% of filling stations sold ULSP but the number has since risen rapidly. In 2005, a new European law was introduced to limit the amount of sulfur in fuel for road vehicles to 50 parts per million (ppm), and said that fuel with a maximum sulfur content of 10 ppm should also be available. All fuel sold had to meet this lower limit by 2009. 1
a
What does sulfur form when it burns?
b
Write a word equation to show this reaction.
H c Write a balanced equation to show this reaction. 2
Why is the presence of sulfur in fuel a problem? Explain in as much detail as you can.
3
Suggest what would have happened if the government had taken no action to reduce the amount of sulfur in vehicle fuel.
4
Suggest why most people did not buy low-sulfur fuels until the government reduced the tax on them.
5
At present, filling stations do not have any pumps marked 'low-sulfur fuels'. Suggest why this is.
Extra challenge 6
What is the maximum mass of sulfur that 1 kg of petrol was allowed to contain: a
in 2005
b
in 2009?
Give your answers in milligrams (1000 mg = 1 g)
Š Pearson Education 2010. Edexcel GCSE Science Activity Pack This document may have been altered from the original.