Which formula can be used to calculate the molar mass of ammonia (NH3)? Molar mass of N + molar mass of H
3 × molar mass of N + molar mass of H
molar mass of N + 3 × molar mass of H
3 × molar mass of N + 3 × molar mass of H

c

Explanation:

Im not 100% sure but i will check in after the test but im pretty sure thats right.

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%