Avogadro's Number and Moles Exercise Sheet
Answers 

1.  What are the units of molar mass? 
2.  The mass of 2.5 X 10^{4} grapes is 50 kilograms, and
that of an equal number of oranges is 1.2 X 10^{3 }kg. What is the mass ratio of a single single grape to a single orange? 
3.  A mole of carbon atoms has a mass of 12 grams, and a mole of
magnesium atoms, 24 grams. What is the mass ratio of a single carbon atom to a single magnesium atom? 
4.  Aluminum and oxygen combine in a mass ratio of 9.00 to 8.00.
If a flashbulb contains 5.4 X 10^{3} grams of aluminum, what mass of oxygen must be present for complete combustion of the aluminum? 
5.  If there are 'x' atoms in 5 grams of carbon, how many atoms
are there in 5 grams of silicon? 
6.  If 10 grams of iron contain 'y' atoms, how many grams of aluminum
will contain 'y' atoms. 
7.  If 8 grams of oxygen contain 3.01 X 10^{23} atoms,
calculate the number of atoms present in 2 grams of oxygen. 
8.  Using Avogadro's number, calculate the number of atoms in 0.005
kilograms of carbon. 