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How many grams of oxygen gas are necessary to react completely with 3.01 × 10^21 atoms of magnesium to yield magnesium oxide?

a) 3.01 g
b) 4.84 g
c) 8.00 g
d) 12.06 g

1 Answer

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Final answer:

To find the grams of oxygen gas needed to react with 3.01 × 10²¹ atoms of magnesium, we use stoichiometry. However, the calculation gives 0.0800 g of oxygen gas, which does not match the provided options.

Step-by-step explanation:

To determine how many grams of oxygen gas are necessary to react completely with 3.01 × 10²¹ atoms of magnesium to yield magnesium oxide, we need to use stoichiometry based on the balanced chemical equation for the reaction of magnesium with oxygen:

2Mg + O₂ → 2MgO

First, we calculate the number of moles of magnesium atoms using Avogadro's number:

3.01 × 10²¹ atoms Mg × (1 mole Mg / 6.022 × 10²³ atoms) = 5.00 × 10⁻³ moles Mg

According to the balanced equation, 1 mole of O₂ reacts with 2 moles of Mg. Therefore, the moles of O₂ needed for the reaction are half the moles of Mg:

5.00 × 10⁻³ moles Mg × (1 mole O₂ / 2 moles Mg) = 2.50 × 10⁻³ moles O₂

Now, we convert moles of oxygen gas to grams using the molar mass of O₂ (32.00 g/mol):

2.50 × 10⁻³ moles O₂ × (32.00 g O₂ / 1 mole O₂) = 0.0800 g O₂

Since 0.0800 g of O₂ is needed and this is not an option in the multiple-choice answers, there seems to be a discrepancy. Please double-check the provided answer choices and the details of the question to ensure there is no mistake.

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