If I have 0.376 g of air, what are the moles of air, and what is the molar mass of air (g/mol)? Please show how to get the answer.

10.88g

Explanation:

The main components of dry air are N2 at 78.08% vol , O2 at 20.95% vol, and Argon at 0.934% vol. We will not be concerned with the lesser components because they will not have a significant effect on our answer.  First we need to find the molar mass of dry air so we use the formula Mass = (percent mass * molar mass of gas) we then plug and chug: MM = (0.7804 * 28.01) + (0.2095 * 31.99)+(0.00934 * 39.95) which gives MM = 28.93 mol/gram

Now that we have the molar mass we use conversion factors to get 0.376g / 28.93mol = 10.88g

answer

the ions in solute supperate from eachouthere

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%