Fertiliser Questions

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March 2013

11. Different processes used in the preparation of fertilisers C and F are represented in the flow diagram below.



11.1 Write down the NAME or FORMULA of:
11.1.1 Gas A (1)
11.1.1 nitrogen gas

11.1.2 Gas B (1)
11.1.2 Hydrogen

11.1.3 Fertiliser F (1)
11.1.3 Ammonium nitrate
            NH4NO3

11.2 Sulphuric acid is used to prepare fertiliser C.
Write down:
11.2.1 The name of the industrial process used to prepare sulphuric acid (1)
11.2.1 Contact process

11.2.2 A balanced equation for the preparation of fertiliser C (3)
11.2.2

11.3 Gases D and E are prepared during the Ostwald process. Write down the:
11.3.1 Name given to the preparation of gas D from ammonia (1)
11.3.1 Catalytic oxidation of ammonia

11.3.2 Balanced equation for the preparation of gas D (3)
11.3.2


11.3.3 NAME or FORMULA of gas E (1)
Nitrogen dioxide / NO2


March 2012

7. The rapidly increasing human population is resulting in an ever-increasing demand for food. To meet this demand, farmers apply fertiliser to the same cultivated land EACH YEAR.

7.1 Explain why farmers have to apply fertilisers to their land EACH YEAR. (2)
7.1 Fertilisers replenish nutrients depleted by growing of crops.

7.2 Write down ONE negative impact that OVERFERTILISATION can have on humans. (2)
7.2 Any ONE
• Damage to crops / soil resulting in small or no harvest./ less income.
• Excessive fertiliser seeps into groundwater and contaminates drinking water.
• Excessive fertiliser run-off into rivers and dams and cause eutrophication that may result in less income./starvation./poor quality of drinking water./ fewer recreation areas.

7.3 Sulphuric acid is an important substance used in the manufacture of fertilisers. The equation below represents one of the steps in the industrial preparation of sulphuric acid.



7.3.1 Write down the name of the process used to prepare sulphuric acid in industry. (1)
7.3.1 Contact process

7.3.2 Write down the NAME or FORMULA of the catalyst used in the process in QUESTION 7.3.1. (1)
7.3.2 vanadium pentoxide / V2O5

7.3.3 Is the forward reaction exothermic or endothermic? Give a reason for the answer. (2)
7.3.3 Exothermic
        ΔH < 0

7.3.4 Write down the NAME or FORMULA of the fertiliser formed when sulphuric acid reacts with ammonia. (2)
7.3.4 ammonium sulphate
        (NH4)2SO4


Nov 2012

11.1 The flow diagram below represents processes used in the fertiliser industry.



Write down:
11.1.1 The name of industrial process X (1)
11.1.1 Fractional distillation of liquid air

11.1.2 A balanced equation for process Y (3)
11.1.2


11.1.3 The name of industrial process Z (1)
11.1.3 Contact (process)

11.1.4 A balanced equation for the preparation of ammonium sulphate using acid R (3)
11.1.4


11.1.5 The name of the type of reaction taking place in QUESTION 11.1.4. (1)
11.1.5 Neutralisation / Acid-base reaction

11.2 Ammonium nitrate is one of the most common compounds used as fertiliser.
11.2.1 Write down the NAME or FORMULA of the acid needed to prepare ammonium nitrate from ammonia. (1)
11.2.1 Nitric acid / HNO3 / hydrogen nitrate

11.2.2 Write down TWO properties of ammonium nitrate that make it suitable for use as a fertiliser. (2)
11.2.2 • Contains (a high percentage of) nitrogen / N / primary nutrient.
            • High solubility


March 2011

7 Fertilisers allow farmers to grow crops in the same soil year after year. However, environmental problems, such as eutrophication, are associated with the application of fertilisers.

7.1 State ONE PRECAUTION that a maize farmer can take to prevent eutrophication. (1)
7.1 ANY ONE:
• Use fertilisers sparingly. / Do not over-fertilise.
• Make use of precision (computerised) application of fertilisers.
• Ensure that water from fields does not run into rivers/dams.
• Redirect water from fields into reservoirs/away from rivers/dams.

Nitric acid is an important reactant in the production of ammonium nitrate, a nitrogenbased fertiliser.

7.2 Write down the name of the industrial process for the production of nitric acid. (1)
7.2 Ostwald Process

7.3 Write down a balanced equation for the preparation of ammonium nitrate from nitric acid. (3)
7.3



Nov 2011

11 Nitric acid is used in the preparation of fertiliser. The flow diagram below shows the three steps (A, B and C) in the industrial preparation of nitric acid.



11.1 Write down the following:
11.1.1 Name of this industrial process in the preparation of nitric acid (1)
11.1.1 Ostwald process

11.1.2 Balanced equation for step B (3)
11.1.2

11.2 NH3(g) reacts with O2(g) to form two products in step A. One of the products is nitrogen(II) oxide. Write down the NAME or FORMULA of the OTHER product. (1)
11.2 water / H2O

11.3 In step C, water is added to the reaction mixture. This step can be represented by the following incomplete equation:



Copy the above incomplete equation into your ANSWER BOOK, fill in the missing reactant and balance the equation. (2)
11.3

11.4 A 50 kg bag of fertiliser is labelled as shown in the diagram below.



Calculate the mass of nitrogen present in this bag of fertiliser. (3)
11.4.





11.5 Uncontrolled use of fertiliser may cause excess fertiliser to run down into streams and rivers, leading to eutrophication.

State ONE negative impact that eutrophication in water may have on humans. (2)
11.5 ANY ONE
• Fish / Aquatic life dies. Results in loss of income / jobs / food.
• Leads to poor water quality. Not enough drinking water. / Poses health risk.
• Water recreation areas become unattractive / dangerous. / Lack of income due to decline in tourism. / Less recreation facilities.

March 2010

12 A learner who is revising for a test on fertilisers, summarises her notes as follows:



12.1 Write down the NAME of the industrial process in Step I used to extract nitrogen gas from the atmosphere. (1)
12.1 Fractional distillation

12.2The Haber process, indicated in Step II, is represented by the following equation:



In this process, high temperatures of approximately 4500C are used.

Explain in terms of reaction rate, equilibrium and temperature why such a high temperature, and not a lower temperature, is used. (4)
12.2 Low temperature increases the amount of NH3. But the rate is too slow.
 At higher temperature NH3 is produced at a faster rate. 

12.3 Write a balanced chemical equation for the reaction that produces the nitrogen fertiliser in Step IV. (3)
12.3

12.4 The learner decides to educate the community about the possible negative effects of the overuse of nitrogen fertilisers on the environment.

Write down the main arguments that she will raise to convince the community to avoid excessive use of nitrogen fertilisers. (4)
12.4 • Rain washes excess of fertilisers into dams, lakes, streams and rivers causing eutrofication that leads to dead zones.
 • Excessive fertiliser in the environment promotes excessive alien growth at the expense of indigenous plants. 
• Groundwater can be contaminated when excessive fertiliser seeps into it. 
• Nitrates in water that can result in blue baby syndrome. 

Blue baby syndrome (or simply, blue baby) occurs when newborn babies have cyanotic heart defects. Drinking water nitrate levels at or above a certain level have been known to cause a potentially fatal blood disorder in infants under six months of age called methemoglobinemia or "blue-baby" syndrome; in which there is a reduction in the oxygen-carrying capacity of blood.

12.5 The learner notes that fertiliser with an NPK ratio of 7:1:1 is needed for the growth of maize plants.
12.5.1 State what the term NPK ratio means. (2)
12.5.1 The ratio (proportion) in which nitrogen, phosphorous and potassium occurs in a certain quantity of fertiliser. 

12.5.2 Will the fertiliser with this NPK ratio lead to a good crop yield?
Explain the answer. (3)
12.5.2 No
The higher proportion of N will enhance leaf growth and less crops. 


Nov 2010

7 Ammonia, ammonium nitrate and ammonium sulphate are three important nitrogen-containing fertilisers. The flow diagram below shows how these fertilisers are produced in industry.



7.1 Use the information in the flow diagram above and write down the following:
7.1.1 Name of Process 1 (1)
7.1.1 Fractional distillation of liquid air

7.1.2 Balanced equation for Process 2 (3)
7.1.2


7.1.3 NAME or FORMULA of compound X (1)
7.1.3 Nitric acid / HNO3

7.1.4 Balanced equation for the preparation of ammonium sulphate using sulphuric acid and compound Y (3)
7.1.4


7.1.5 NAME or SYMBOL of the primary nutrient in ammonium sulphate (1)
7.1.5 Nitrogen / N

7.2 Write down ONE positive impact of fertilisers on humans. (2)
7.2 Any ONE:
• Enhance growth of crops/plants to produce more food for humans / food security for humans.
• Production/application of fertiliser 9 results in job creation.
• Selling of fertilisers 9 stimulates the economy.

7.3 Write down TWO negative impacts of the use of ammonium nitrate, as fertiliser, on humans. (4)
7.3 Any TWO:
• (Excessive) nitrates in water (eutrophication) can result in bluebaby syndrome / cancer.
• (Excessive) nitrates/ammonium ions in water can result in poor quality drinking water.
• (Excessive) nitrates / ammonium ions in water cause death of fish (eutrophication) can result in less food.
• (Excessive) nitrates /ammonium ions in water (eutrophication) can result in poorer water recreational facilities.
• (Excessive) nitrates in soil kill plants/crops9 resulting in food shortages / famine.
• (Excessive) ammonium ions in soil increases the acidity of the soil limiting food production.

Blue baby syndrome (or simply, blue baby) occurs when newborn babies have cyanotic heart defects. Drinking water nitrate levels at or above a certain level have been known to cause a potentially fatal blood disorder in infants under six months of age called methemoglobinemia or "blue-baby" syndrome; in which there is a reduction in the oxygen-carrying capacity of blood.


March 2009

12 About one third of the protein consumed by humans comes from fertilisers. The flow diagram below shows three industrial processes, A, B and C, that result in the production of fertilisers.



12.1 Write down the name of the Process A. (1)
12.1 Fractional distillation of (liquid) air

12.2 Write down the balanced equation for the reaction which takes place in process B. (3)
12.2

12.3 Write down the balanced equation for step 2 of Process C. (3)
12.3

12.4 Write down the FORMULA and the NAME of product X in step 3 of Process C. (2)
12.4 H2S2O7
Oleum / pyrosulphuric acid

12.5 Write the FORMULA and the NAME of the fertiliser represented by Y. (3)
12.5 (NH4)2SO4
Ammonium sulphate

12.6 Fertiliser prices increased by more than 200 per cent since 2007. This rise is fuelled by new demand.
12.6.1 Give TWO reasons why there is a continuous demand for fertilisers. (2)
12.6.1 • Soil cannot replenish nutrients at a fast enough rate to sustain growth.
• Globally a bigger demand for food

12.6.2 Give TWO reasons why there is an increase in the price of fertilisers. (2)
12.6.2 • Increase in oil price
            • Increase in price of raw materials


Nov 2009 Unused



10.1 Write a balanced equation for the reaction in Step II. (3)
10.1

10.2 What is the name of the industrial process represented by Step III? (1)
10.2 Contact process

10.3 Write down a balanced chemical equation for Step IV. (3)

10.4 A community is protesting against a fertiliser plant being set up close to a lake, which is their only source of drinking water.
Give TWO reasons to justify their protest. (2)
10.4 Any TWO
• Leakage of the fertiliser into the water may lead to eutrophication that can lead to a decrease in water quality.
• The leakage of fertiliser into their only source of drinking water may lead to blue baby syndrome when consumed.
• The leakage of fertiliser into their only source of water can result in the death of fish used as food.
• Source of drinking water

Blue baby syndrome (or simply, blue baby) occurs when newborn babies have cyanotic heart defects. Drinking water nitrate levels at or above a certain level have been known to cause a potentially fatal blood disorder in infants under six months of age called methemoglobinemia or "blue-baby" syndrome; in which there is a reduction in the oxygen-carrying capacity of blood.


Nov 2008

DEAD ZONES EMERGING AS A BIG THREAT TO 21ST CENTURY FISH STOCKS
There are nearly 200 oxygen-starved or 'dead' zones in the world's oceans and seas. These 'dead' zones are linked to eutrophication caused by agricultural fertilisers, vehicle and factory emissions and wastes. Low levels of oxygen in the water make it difficult for important habitats such as sea grass beds, as well as organisms such as fish, oysters and other marine creatures, to survive. Nitrogen shortages are reducing farmers' chances of meeting food demands in parts of Africa. In many other parts of the world, however, excessive use of fertilisers is contributing to the escalating problem of 'dead' zones.
[Adapted from: United Nations environmental programme, News Centre, 2006]

12.1 Describe the process of eutrophication in water and how it leads to dead zones. (4)
12.1 Nitrogen-rich (and phosphorous) nutrients (fertilisers) get into water.
This causes rapid growth of algae (algal bloom).
Depletion of oxygen occures when algae die, since their decomposition by bacteria removes oxygen from water
Living organisms die. Water with a low dissolved oxygen content is said to be hypoxic.

12.2 Natural eutrophication takes place over thousands of years. Humans accelerate this process.
Name TWO ways in which they do this. (2)
12.2 Any two
• Over-application of fertilisers
• Emissions from vehicles
• Factory emissions
• Sewage; waste disposal systems
• Stock farming

12.3 The flow diagram below represents the conversion of ammonia into nitrates.



12.3.1 What is the name of Process X?
12.3.1 Catalytic oxidation of ammonia

12.3.2 Write down a balanced equation for Process X. (3)
12.3.2

12.3.3 Write down the FORMULA for Gas Y. (2)
12.3.3 NO2

12.3.4 Write down a balanced equation for the preparation of fertiliser P.
12.3.4


OR


12.4 Name TWO ways according to which eutrophication can be reduced. (2)
12.4 Any two
• Control (reduce) the use of fertilisers / Use organic fertilisers / compost
• Control (reduce) waste disposal
• Control vehicle and factory emissions, etc.


Prep Paper 2008

12 Read the passage below and answer the questions that follow.



Plants are an important natural resource. In addition to their many other benefits, they produce:

Food by photosynthesis and
Coal through plant decay and compaction over million of years.

Coal is a non-renewable resource and is used by industry, for example SASOL to produce fuels.

Global concerns around the production of fuels include the following:
• The growing shortages of both fuel and food.
• The depletion of non-renewable resources
• Population growth and increasing demands on natural resources
• Global warming, climate change and environmental degradation

A growing demand for fuel, together with its anticipated shortage, is intensifying the search for alternate methods of fuel production. Some organisations favour the production of biofuels from food crops claiming that it will help against climate change and environmental degradation. Others argue against it claiming that unintended consequences can have advers effects on the world's starving population.

12.1. What argument is used for the following:
12.1.1. In support of the production of biofuels (1)
12.1.1. Production will not contribute to global warming / fight against climate change and environmental degradation.

12.1.2. Against the production of biofuels (1)
Production of biofuels will contribute to food shortage

12.2 What is a non-renewable resource? (1)
Resource that CANNOT be regenerated
CAN be used up

12.3. Name TWO risks of using coal or oil for fuel production. (2)
12.3. Pollution during combustion and thus climate change
Mining affects environments eg. plant growth that is destroyed in area of mining

12.4 Name TWO reasons why the increase in fuel price results in an increase in food prices. (2)
12.4. Fertilizers become more expensive
Transport costs increase
More food is used for bio-fuels

12.5 Why would the excessive use of fertilisers be problematic? Explain. (3)
Can result in leaching into water resources
Excessive growth of algae / alien plants that leads to eutrophication
Deterioration of soil quality

12.6 The Haber Process is used in the production of fertilisers.
12.6.1 The Haber Process supplies one primary nutrient for plants. Name this nutrient. (1)
Nitrogen

12.6.2 What function does this primary nutrient serve in plants? (1)
Enhance growth

12.6.3 Name TWO ways in which the Haber Process is dependant on fuel. (2)
Heating and compression

12.6.4 Write a balanced chemical equation for the chemical change that occurs in the Haber Process. (3)
12.6.4


12.6.5 Name ONE disadvantage of the use of inorganic fertilisers prepared through the Haber Process. (2)
12.6.5. Leads to eutrophication (algae bloom) and deterioration of soil quality


Exemplar 2008

14 Why we need fertilisers



There is likely to be a gap between food production and demand in several parts of the world by 2020. Demand is influenced by population growth and urbanisation, as well as income levels and changes in dietary preferences.
The facts are as follows:
Conclusion: Fertilisers are needed!

The flow diagram below shows the main steps in the industrial preparation of two important solid fertilisers.



14.1 Write down the balanced chemical equation for the formation of the brown gas. (3)
14.1

14.2 Write down the name of process Y. (2
14.2 Catalytic oxidation of ammonia

14.3 Write down the chemical formula of liquid E. (2)
14.3
HNO3

14.4 Write down the chemical formulae of fertilisers C and D respectively. (4)
14.4
D - (NH4)2SO4
E - NH4NO3

The following extract comes from an article on fertilisers:
A world without food for its people -
A world with an environment poisoned through the actions of man -
Are two contributing factors towards a disaster scenario.


14.5 Write down THREE ways in which the use of fertilisers poisons the environment. (6)
Any three

Additional Exemplar 2008

13.1 The flow diagram below shows processes and reactions that lead to the formation of a nitrogen-based fertiliser S.



13.1.1 Write down the NAME for product X. (1)
13.1.1 Ammonia

13.1.2 Write down the NAME for Process Q. (1)
13.1.2 Ostwald process

13.1.3 Write down the FORMULA for fertiliser S. (2)
13.1.3 NH4NO3

13.1.4 Write down the FORMULA for fertiliser S if the nitric acid is replaced with sulphuric acid. (2)
13.1.4 (NH4)2SO4

13.2 A farmer stores fertilisers with NPK ratios 4:5:8 and 13:5:9. The farmer wants to grow tomatoes and fruit.
13.2.1 Explain the meaning of NPK ratio. (2)
13.2.1 The NPK ratio gives the proportion / ratio of nitrogen, phosphorous and potassium in a fertiliser.

13.2.2 Which ONE of these fertilisers must he use? (1)
13.2.2 Use ratio 4:5:8

13.2.3 Give a reason for your answer to QUESTION 13.2.2. (2)
13.2.3 Lower N to prevent too much leaf growth at the cost of fruit growth.

13.3 Overuse of nitrogen-based fertilisers creates problems for the environment and humans.

Name ONE threat posed by nitrogen-based fertilisers to the environment and ONE threat posed to humans. (2)
13.3
Environment:
Eutrophication
 OR
Dead zones

Humans:
water poisoning
OR
blue baby syndrome
OR
nitrates potentially carcinogenic







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