5 multiple choice 10 points determine the mass percent of c in sodium bicarbonate (nahco₃) 14.28% 50.00%…

5.

Explanation:

Step1: Calculate molar mass of NaHCO₃

The molar mass of Na (sodium) is approximately 22.99 g/mol, H (hydrogen) is approximately 1.01 g/mol, C (carbon) is approximately 12.01 g/mol, and O (oxygen) is approximately 16.00 g/mol. For NaHCO₃, (M = 22.99+1.01 + 12.01+3\times16.00=84.01) g/mol.

Step2: Calculate mass - percent of C

The mass - percent of C is (\frac{12.01}{84.01}\times100%\approx14.28%)

Answer:

14.28%

6.

Explanation:

Step1: Assume 100 g of the compound

If we assume 100 g of the compound, then the mass of lead (Pb) is 90.6 g and the mass of oxygen (O) is 9.4 g.

Step2: Calculate moles of each element

The molar mass of Pb is approximately 207.2 g/mol and of O is 16.00 g/mol. Moles of Pb, (n_{Pb}=\frac{90.6}{207.2}\approx0.437) mol. Moles of O, (n_O=\frac{9.4}{16.00}\approx0.5875) mol.

Step3: Find the mole - ratio

Divide each number of moles by the smaller number of moles ((n_{Pb} = 0.437) mol). For Pb, (\frac{0.437}{0.437}=1). For O, (\frac{0.5875}{0.437}\approx1.35). Multiply by 3 to get whole - number ratios. We get (Pb_3O_4).

Answer:

(Pb_3O_4)