Final answer:
The mass of oxygen formed when 20.0 g of dinitrogen monoxide decomposes is calculated using stoichiometry based on the balanced chemical equation and is found to be 7.27 g. The correct option is option (a) 7.27 g.
Step-by-step explanation:
To determine how many grams of oxygen are formed when 20.0 g of dinitrogen monoxide decomposes, we should first write the balanced chemical equation for the decomposition reaction:
N2O(g) → N2(g) + 1/2 O2(g)
We know that dinitrogen monoxide has a molar mass of approximately 44 g/mol (28 g/mol from N2 and 16 g/mol from O), and oxygen gas has a molar mass of approximately 32 g/mol (16 g/mol from each of the two oxygen atoms in O2).
Using stoichiometry, we can calculate the mass of oxygen produced:
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- Calculate the moles of N2O in 20.0 g:
20.0 g N2O x (1 mol N2O/44 g N2O) = 0.455 mol N2O
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- Using the mole ratio from the balanced equation, calculate the moles of O2 produced: 0.455 mol N2O x (1/2 mol O2/1 mol N2O) = 0.228 mol O2
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- Calculate the mass of O2 from the moles obtained: 0.228 mol O2 x (32 g O2/mol) = 7.27 g O2
Therefore, the mass of oxygen formed is 7.27 g which is the correct option from the given choices.