This question is about metals and metal compounds - AQA - GCSE Chemistry - Question 2 - 2018 - Paper 1
Question 2
This question is about metals and metal compounds.
Iron pyrites is an ionic compound.
Figure 1 shows a structure for iron pyrites.
Determine the formula of iron p... show full transcript
Worked Solution & Example Answer:This question is about metals and metal compounds - AQA - GCSE Chemistry - Question 2 - 2018 - Paper 1
Step 1
Determine the formula of iron pyrites.
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Answer
The formula for iron pyrites is (FeS_{2}), indicating that for every iron atom, there are two sulfur atoms.
Step 2
Number of protons
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Answer
The number of protons in an atom of iron is 26.
Step 3
Number of neutrons
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Answer
The number of neutrons can be calculated by subtracting the atomic number from the mass number: (56 - 26 = 30). Therefore, the number of neutrons is 30.
Step 4
Number of electrons
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Answer
In a neutral atom, the number of electrons equals the number of protons, thus there are 26 electrons.
Step 5
Give two differences between the properties of iron and sodium.
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Answer
Iron has a higher melting and boiling point than sodium.
Iron is denser and stronger than sodium; sodium is softer and more reactive.
Step 6
Explain why carbon can be used to extract nickel from nickel oxide.
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Carbon can be used to extract nickel from nickel oxide because it is more reactive than nickel, allowing it to displace nickel during the reduction process.
Step 7
Calculate the percentage atom economy for the reaction to produce nickel.
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Answer
First, we calculate the total molar mass of reactants: (M_f = NiO + C = 75 + 12 = 87).
The percentage atom economy is given by:
[
\text{Percentage Atom Economy} = \left( \frac{\text{Molar Mass of Desired Product}}{\text{Total Molar Mass of Reactants}} \right) \times 100 = \left( \frac{59}{87} \right) \times 100 \approx 67.8%
]
Thus, the final answer to 3 significant figures is 67.8%.
