1 How many moles does 4.015x10²³ molecules of hydrogen represent?

2 Calculate the molar mass of Ni(NO₃)₂.

3 How many grams of Fe(OH)₂ are in 2.85 mole of Fe(OH)2.

4 What is the percent composition of each element in K₂CO₃?

5 Find the empirical formula for a compound containing 34.44% nitrogen and 65.56% oxygen by mass.

6 Assuming that the molecular weight for the compound found in problem 5 is 366.1 g/mole, what is the molecular formula for the compound?