Question

Alanine is an amino acid with the formula C3H7NO2. Determine the number of moles of carbon in 61.23 g of alanine.

Answer 1

2.061 moles

Explanation

Atomic mass of C = 12.011g/mol

Mass of C in one mole of C3H7NO2 = 3× 12.011g = 36.033g

Atomic mass of H = 1.008g/mol

Mass of H in one mole of C3H7NO2 = 7×1.008g = 7.056g

Atomic mass of N = 14.007g/mol

Mass of N in one mole of C3H7NO2 = 1×14.007g = 14.007g

Atomic mass of O = 16g/mol

Mass of O in one mole of C3H7NO2 = 2× 16g = 32g

Molar mass of C3H7NO2 = 36.033g + 7.056g + 14.007g + 32g = 89.096g/mol

Mass % of C in C3H7NO2 = (36.033g/89.096g)×100 = 40.44%

Mass of C in 61.23g of C3H7NO2 =( 40.44/100)× 61.23g = 24.76g

No of moles = Mass /molar mass

mass of C = 24.76g

Molar mass of C= 12.011g/mol

No of moles of C = 24.76g/12.011g/mol = 2.061mol