This question is about the extraction of metals. Element R is extracted from its oxide by reduction with hydrogen. The equation for the reaction is: $$3H_2 + RO_3 \rightarrow R + 3H_2O$$ The sum of the relative formula masses (M_f) of the reactants (3H_2 + RO_3) is 150. Calculate the relative atomic mass (A_r) of R. Relative atomic masses (A_r): H = 1 O = 16 Identify element R. You should use: • your answer to question 03.1 • the periodic table. Carbon is used to extract tin (Sn) from tin oxide (SnO_2). The equation for the reaction is: $$SnO_2 + C \rightarrow Sn + CO_2$$ Calculate the percentage atom economy for extracting tin in this reaction. Relative atomic masses (A_r): C = 12 O = 16 Sn = 119 Tungsten (W) is a metal. Tungsten is extracted from tungsten oxide (WO_3). All other solid products from the extraction method must be separated from the tungsten. Table 2 shows information about three possible methods to extract tungsten from tungsten oxide. Evaluate the three possible methods for extracting tungsten from tungsten oxide.

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This question is about the extraction of metals - AQA - GCSE Chemistry - Question 3 - 2021 - Paper 1

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This question is about the extraction of metals. Element R is extracted from its oxide by reduction with hydrogen. The equation for the reaction is: $$3H_2 + RO_3... show full transcript

Worked Solution & Example Answer:This question is about the extraction of metals - AQA - GCSE Chemistry - Question 3 - 2021 - Paper 1

Step 1

Calculate the relative atomic mass (A_r) of R.

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Answer

To find the relative atomic mass (A_r) of element R, we first note that the sum of the relative formula masses of the reactants is given as 150. The formula for the mass of the reactants is:

$M_f = 3M_{H_2} + M_{R}O_3$

Calculating the mass of the hydrogen:

Since each hydrogen atom has a relative atomic mass of 1, the total mass contributed by 3 moles of hydrogen is:

$M_{H_2} = 2H = 2 imes 1 = 2$

Therefore,

$3M_{H_2} = 3 imes 2 = 6$

Substituting this back into the equation:

$6 + M_{R}O_3 = 150$

To find $M_{R}O_3$ , we rearrange:

$M_{R}O_3 = 150 - 6 = 144$

Now, using the molar mass of oxygen (16), we can calculate:

$M_{R} = 144 - 3 imes 16 = 144 - 48 = 96$

Thus, the relative atomic mass of R is 96.

Step 2

Identify element R.

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Answer

Using the periodic table, the element with a relative atomic mass of 96 is molybdenum (Mo).

Step 3

Calculate the percentage atom economy for extracting tin.

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Answer

The total relative formula mass of the reactants is calculated as follows:

$M_{f}(reactants) = M_{SnO_2} + M_{C} = (119 + 16) + 12 = 163$

The total mass of the desired product is the mass of tin, which is 119. The percentage atom economy can be calculated using the formula:

$\text{Percentage atom economy} = \left(\frac{\text{Mass of desired product}}{\text{Total mass of reactants}}\right) \times 100$

Substituting in our values:

$\text{Percentage atom economy} = \left(\frac{119}{163}\right) \times 100 \approx 73\%$

Step 4

Evaluate the three possible methods for extracting tungsten.

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Answer

Carbon: This is the cheapest reactant but produces carbon dioxide, which is a greenhouse gas. Additionally, separating the solid products can be expensive and time-consuming.
Hydrogen: This method has a high relative cost but produces water vapour, which can escape without significant waste.
Iron: Iron is the most expensive reactant here, and separating the solids would also take considerable time and resources.

In conclusion, while carbon is the least expensive option, it has significant environmental implications. Hydrogen, while costly, offers a cleaner output. Lastly, iron is inefficient and costly, making it a less favorable option.

This question is about the extraction of metals - AQA - GCSE Chemistry - Question 3 - 2021 - Paper 1

Worked Solution & Example Answer:This question is about the extraction of metals - AQA - GCSE Chemistry - Question 3 - 2021 - Paper 1

Calculate the relative atomic mass (A_r) of R.

Identify element R.

Calculate the percentage atom economy for extracting tin.

Evaluate the three possible methods for extracting tungsten.

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