Question

Determine the mass of oxygen in a 5.8 g sample of sodium bicarbonate (NaHCO3).

Answer 1

To determine the mass of oxygen in a 5.8 g sample of sodium bicarbonate (NaHCO3), calculate the molar mass of NaHCO3, then use the mole ratio to convert the mass of NaHCO3 to the mass of oxygen.

Step-by-step explanation:

To determine the mass of oxygen in a 5.8 g sample of sodium bicarbonate (NaHCO3), we need to consider the molar mass of NaHCO3. The molar mass of NaHCO3 is the sum of the atomic masses of its constituent elements. Na has an atomic mass of 22.990 g/mol, H has an atomic mass of 1.008 g/mol, C has an atomic mass of 12.01 g/mol, and O has an atomic mass of 15.999 g/mol.

So, the molar mass of NaHCO3 is:

(22.990 g/mol x 1) + (1.008 g/mol x 1) + (12.01 g/mol x 1) + (15.999 g/mol x 3) = 84.007 g/mol

To calculate the mass of oxygen in the 5.8 g sample of NaHCO3, we can multiply the mass of the sample by the mole ratio of oxygen to NaHCO3. The mole ratio is 3 moles of oxygen for every 1 mole of NaHCO3.

(5.8 g NaHCO3) x (3 mol O / 1 mol NaHCO3) x (15.999 g/mol) = 275.92 g

Therefore, the mass of oxygen in the 5.8 g sample of NaHCO3 is 275.92 g.

Answer 2

Answer is: the mass of oxygen is 3.31 grams.

m(NaHCO₃) = 5.8; mass of sodium bicarbonate.

n(NaHCO₃) = m(NaHCO₃) ÷ M(NaHCO₃).

n(NaHCO₃) = 5.8 g ÷ 84 g/mol.

n(NaHCO₃) = 0.07 mol; amount of sodium bicarbonate.

In one molecule of sodium bicarbonate there are three oxygen atoms:

n(NaHCO₃) : n(O) = 1 : 3.

n(O) = 3 · 0.07 mol.

n(O) = 0.21 mol.

m(O) = 0.21 mol · 16 g/mol.

m(O) = 3.31 g.