GCSE OCR Gateway Chemistry 3.2 Calculating Mass of Substances: Oxygen reacts with 1.20 g of car

Oxygen reacts with 1.20 g of carbon - OCR Gateway - GCSE Chemistry - Question 13 - 2020 - Paper 1

Question 13

Oxygen reacts with 1.20 g of carbon. 4.40 g of carbon dioxide forms. C + O2 → CO2 What mass of oxygen is used in this reaction?

Worked Solution & Example Answer:Oxygen reacts with 1.20 g of carbon - OCR Gateway - GCSE Chemistry - Question 13 - 2020 - Paper 1

Step 1

Step A: Analyze the Chemical Equation

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Answer

The balanced equation shows that one mole of carbon reacts with one mole of oxygen to produce one mole of carbon dioxide. This implies a 1:1 molar ratio between carbon and oxygen.

Step 2

Step B: Determine the Moles of Carbon

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Answer

First, we need to calculate the moles of carbon (C) used in the reaction. The molar mass of carbon is approximately 12.01 g/mol.

The moles of carbon can be calculated using the formula:

ext{Moles of Carbon} = \frac{\text{Mass of Carbon}}{\text{Molar Mass of Carbon}} = \frac{1.20 \, ext{g}}{12.01 \, ext{g/mol}} \approx 0.100 \, ext{mol}

Step 3

Step C: Use Stoichiometry to Find Moles of Oxygen

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Answer

Since the molar ratio of carbon to oxygen is 1:1, the moles of oxygen needed will also be 0.100 mol.

Step 4

Step D: Calculate the Mass of Oxygen

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Answer

Next, we calculate the mass of oxygen needed using its molar mass, which is approximately 32.00 g/mol:

ext{Mass of Oxygen} = \text{Moles of Oxygen} \times \text{Molar Mass of Oxygen} = 0.100 \, ext{mol} \times 32.00 \, ext{g/mol} = 3.20 \, ext{g}

Thus, the mass of oxygen used in the reaction is 3.20 g.

Step 5

Final Answer

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Answer

The correct answer to the question is C) 3.20 g.

Oxygen reacts with 1.20 g of carbon - OCR Gateway - GCSE Chemistry - Question 13 - 2020 - Paper 1

Worked Solution & Example Answer:Oxygen reacts with 1.20 g of carbon - OCR Gateway - GCSE Chemistry - Question 13 - 2020 - Paper 1

Step A: Analyze the Chemical Equation

Step B: Determine the Moles of Carbon

Step C: Use Stoichiometry to Find Moles of Oxygen

Step D: Calculate the Mass of Oxygen

Final Answer

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