Question

The molar mass of the common antibiotic oxytetracycline is found to be 460 g mol^-1 and a 2.000 g sample contains 1.1478 g of carbon, 0.10435 g of hydrogen, 0.62609 g of oxygen, and the remainder being nitrogen. What is the molecular formula of the oxytetracycline ?

Answer 1

Answer:

The molecular formula for oxytetracycline is C₂₂H₂₄O₉N₂

Explanation:

Molar mass oxytetracycline: 460 g/m

Molar mass Carbon: 12 g/m

Molar mass Hydrogen: 1 g/m

Molar mass Oxygen: 16 g/m

Molar mass Nitrogen:

2 grams of compound has:

1.1478 g / 12 g/m = 0.09565 moles of C

0.10435 g / 1 g/m =0.10435 moles of H

0.62609 g / 16 g/m =0.03913 moles of O

2 - 1.1478 - 0.10435 - 0.62609 = 0.12176 g N

0.12176 g / 14g/m = 0.00869 moles of N

By the way, 2 grams of oxytetracycline are 0.00434 moles so

If 0.00434 moles of oxytetracycline have 0.09565 moles of C

1 mol of oxytetracycline, how many moles of C does it has?

0.09565 / 0.00434 = 22 moles of C

0.10435 / 0.00434 = 24 moles of H

0.03913 / 0.00434 = 9 moles of O

0.00869 / 0.00434 = 2 moles of N