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Phosphates

Rock phosphate [Ca 10 (PO 4 ) 6 F 2 ], mined from open pit mines at Phalaborwa, is an important raw material in the production of fertilisers. The following two reactions are used to transform rock phosphate into water soluble phosphates:

  • Ca 10 (PO 4 ) 6 F 2 + 7X + 3H 2 O 3Ca(H 2 PO 4 ) 2 H 2 O + 2HF + 7CaSO 4
  • Ca 10 (PO 4 ) 6 F 2 + 14Y + 10H 2 O 10Ca(H 2 PO 4 ) 2 H 2 O + 2HF
  1. Identify the acids represented by X and Y.
  2. Despite similar molecular formulae, the products Ca(H 2 PO 4 ) 2 formed in the two reactions have different common names. Write down the names for each of these products in reactions A and B.
  3. Refer to the products in reactions A and B and write down TWO advantages of reaction B over reaction A.
  4. Why is rock phosphate unsuitable as fertiliser?
  5. State ONE advantage and ONE disadvantage of phosphate mining.

(DoE Exemplar Paper, Grade 11, 2007)

Case study : controversy on the wild coast - titanium mining

Read the extract below, which has been adapted from an article that appeared in the Mail and Guardian on 4th May 2007, and then answer the questions that follow.

A potentially violent backlash looms in Pondoland over efforts by an Australian company to persuade villagers to back controversial plans to mine an environmentally sensitive strip of the Wild Coast. The mining will take place in the Xolobeni dunes, south of Port Edward. The application has outraged environmental groups, largely because the proposed mining areas form part of the Pondoland centre of endemism, which has more species than the United Kingdom, some of which are endemic and facing extinction.

Exploratory drilling revealed Xolobeni has the world's 10th largest titanium deposit, worth about R11 billion. The amount of money that will be spent over the mine's 22 years, including a smelter, is estimated at R1.4 billion. The Australian mining company predicts that 570 direct jobs will be created.

But at least two communities fiercely oppose the mining plans. Some opponents are former miners who fear Gauteng's mine dumps and compounds will be replicated on the Wild Coast. Others are employees of failed ecotourism ventures, who blame the mining company for their situation. Many are suspicious of outsiders. The villagers have also complained that some of the structures within the mining company are controlled by business leaders with political connections, who are in it for their own gain. Intimidation of people who oppose the mining has also been alleged. Headman Mandoda Ndovela was shot dead after his outspoken criticism of the mining.

Mzamo Dlamini, a youth living in one of the villages that will be affected by the mining, said 10% of the Amadiba 'who were promised riches by the mining company' support mining. 'The rest say if people bring those machines, we will fight.'

  1. Explain what the following words means:
    1. endemic
    2. smelter
    3. ecotourism
  2. What kinds of 'riches' do you think the Amadiba people have been promised by the mining company?
  3. In two columns, list the potential advantages and disadvantages of mining in this area.
  4. Imagine that you were one of the villagers in this area. Write down three questions that you would want the mining company to answer before you made a decision about whether to oppose the mining or not. Share your ideas with the rest of the class.
  5. Imagine that you are an environmentalist. What would your main concerns be about the proposed mining project? Again share your answers with the rest of the class.

Questions & Answers

How do hydrogen and chlorine atoms bond covalently in a molecule of hydrogen chloride?
Tiny Reply
what is the parallel circuit
Philani Reply
how many moles of H2O can be formed if 12,5 moi CH4 reacts with sufficient NH3 and O2
Nomcebo Reply
what atoms form covalent bond
hehe Reply
The combination of two non metals
Ndumiso
combined two non-metals 😊
Trudy
what is a mole
Thandeka Reply
a mole is a measure of large quantities of small entities such as atoms, molecules etc
DINEO
what does STP stand for?
Deeco
STP stands for Standard Temperature and Pressure.
Dolly
A car drives straight off the edge of a cliff that is 54m high. The police at the scene of the accident observed that the point of the impact is 130m from the base of the clif. Calculate the initial velocity of the car when it went ovet the clif.
hanyani Reply
wat happens to current if resistors are in parallel connection
Mosima Reply
more current flows from the source that would flow for any of them individually,so the total total resistance is lower
Theoo
In the parallel circuit the current is divided among the resistors
Ndumiso
what are the isotopes
Tlotlisang Reply
are different types of the same elemant but with different mass or atomic no.
Ayanda
i sotopes are different type of element with same atomic number but different mass number
Tareskay
yes i forgot some details😁
Ayanda
next quetion plz
Tareskay
why don't we insert the negative sign for 5 × 10 - 9 when substituting
Mpho Reply
Why does an enclosed gas exert pressure on the walls of a container
Palesa Reply
State the gay lussacs law
Anna Reply
what is the coefficient of Na in order to balanced the equation?_Na + MgCl2=2NaCl+Mg?
Arcel Reply
2
Okuhle
2
Tlotlisang
2
Praise
2
Anna
2
Anelehr
2
Liyema
the combining power of an element, especially as measured by the number of hydrogen atoms it can displace or combine with.
Dealon Reply
Thanks
REJOYCE
download periodic table from play Store...it will explain everything to u
Dealon
what are orbitals
Sphe Reply
examples of atoms whose Valence energy levels are not full and more to bond and become more stable
Sphe
What is a valency
REJOYCE
What a lone pairs...
Ndumiso
Valency is the number of electrons than an atom must gain, lose or share to achieve noble gas configuration.
Mcebisi
what is vacuum
Njabulo Reply
Vacuum, space in which there is no matter or in which the pressure is so low that any particles in the space do not affect any processes being carried on there. It is a condition well below normal atmospheric pressure and is measured in units of pressure (the pascal).
Khayalethu

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Source:  OpenStax, Siyavula textbooks: grade 11 physical science. OpenStax CNX. Jul 29, 2011 Download for free at http://cnx.org/content/col11241/1.2
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