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1. How many atoms of oxygen are present in 0.04 mole NaNO3?

2. How many moles of nitrogen atoms are present in 10.5g of N2O5?

3. How many atoms of oxygen are present in 50g of Fe(H20)2(S04)3? Please answer fast

Respuesta :

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Answer:

1. 7.227x10²⁴ O atoms

2. 0.1944 mol

3. 3.18x10²³ atoms

Explanation:

1. To solve this problem we need to use Avogadro's number, which states the number of molecules that are in 1 mol of a substance:

  • 0.04 mol NaNO₃ * 6.023x10²³ molecules/mol = 2.409x10²⁴ molecules NaNO₃

There are 3 O atoms per NaNO₃ molecule, thus the answer is (3* 2.409x10²⁴) 7.227x10²⁴ atoms.

2. First we convert 10.5 g of N₂O₅ into moles, using its molar mass:

  • 10.5 g N₂O₅ ÷ 108 g/mol = 0.0972 mol N₂O₅

There are 2 N moles per N₂O₅ mol, thus the answer is (2*0.0972) 0.1944 mol.

3. First we convert grams into moles:

  • 50 g Fe(H₂O)₂(SO₄)₃ ÷ 379.85 g/mol = 0.132 mol

Then we use Avogadro's number:

  • 0.132 mol * 6.023x10²³ molecules/mol = 7.95x10²² molecules Fe(H₂O)₂(SO₄)₃

There are 14 O atoms per Fe(H₂O)₂(SO₄)₃ molecule, so the answer is (7.95x10²² * 4) 3.18x10²³ atoms.

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