End of Chapter Problems

Test your skills on the following problems. 

Mass Conversions

Problem: How many molecules of hexane are contained in 55.0 mL of hexane? The density of hexane is 0.6548 g/mL and the molar mass is 86.17 g/mol.


Problem: How many SO3 ions are contained in 120.0 mg of Na2SO3? The molar mass of Na2SO3 is 126.05 g/mol.


Problem: What mass of phosphorus pentafluoride, PF5, has the same number of fluorine atoms as 50.0 g of oxygen difluoride, OF2?


Problem: How many bromide ions are there in 4.50 moles of gallium bromide?


Problem: How many moles of oxygen atoms are required to combine with 3.05 moles of Pb to create lead (IV) phosphate?


Problem: How many cations are there in 100.0 g of lithium nitride?


Problem: Which of the following amounts would contain the least atoms?

a) 10.0 g Sr

b) 10.0 g Br

c) 10.0 g Mg

d) 10.0 g Li


Problem: Which of the following amounts have the most molecules?

a) 15.0 g N2

b) 15.0 g Br2

c) 15.0 g O2

d) 15.0 g I2