Question

Use the periodic table to calculate the molar mass of each of the following compounds. Each answer must have 2 decimal places.

Ammonia (NH3):
g/mol
Magnesium hydroxide (Mg(OH)2):
g/mol
Iron(III) oxide (Fe2O3):
g/mol

Answer 1

Using standard atomic weights (N 14.01, H 1.008, Mg 24.305, O 15.999, Fe 55.845):

- Ammonia (NH3): 14.01 + 3(1.008) = 17.034 → 17.03 g/mol
- Magnesium hydroxide (Mg(OH)2): 24.305 + 2[15.999 + 1.008] = 58.319 → 58.32 g/mol
- Iron(III) oxide (Fe2O3): 2(55.845) + 3(15.999) = 159.687 → 159.69 g/mol