Question

How many molecules of sodium oxide will be created if 187 grams of oxygen reacts with excess sodium? 4Na + O2 -> 2Na2O A. 11.69 x 1023 molecules of Na2O

Answer 1

Answer:

• 7.04 × 10²⁴ molecules of Na₂O

Explanation:

1) Balanced chemical equation (given):

• 4 Na(s) + O₂ (g) → 2Na₂O (s)

2) Mole ratio:

• 1 mol O₂ : 2 mol Na₂O

3) Number of moles of O₂ in 187 grams of oxygen:

• Molar mass O₂ = 32.00 g/mol

• Number of moles = mass in grams / molar mass = 187 g / 32.00 g/mol = 5.844 mol

4) Number of moles of Na₂O:

• Proportion: 1 mol O₂ / 2 mol Na₂O = 5.844 mol O₂ / x

• x = 5.844 mol O₂ (2 mol Na₂O / 1 mol O₂) = 11.688 mol Na₂O

5) Number of molecules

• Number of molecules = number of moles × Avogadro's number

• Number of molecules = 11.688 mol × 6.022 × 10²³ molecules/mol =

                                               = 7.04 × 10 ²⁴ molecules ← answer

The answer is rounded to three significant figures.