Chapter 10 Review                                     Name __________________________________

                                                                   Period _______ Date______________________

Classify each of these statements as always true, AT, sometimes true, ST, or never true, NT.

_____ 1. A mole of a pure substance contains 6.02 x 1023 atoms.

_____ 2. The representative particle of a compound is a molecule.

_____ 3. A mole of CCl4 is composed of one mole of carbon and 4 mole of chlorine.

_____ 4. One mole of gas occupies 22.4 L

_____ 5. The formula of methane is CH4. If methane contains 75% carbon, then 100 grams of                        methane contains 75 grams of carbon.

_____ 6. The formula for methane, CH4 , is both an empirical and molecular formula.

_____  7. The empirical formula of  C6H12O6 is C2H4O2.


Solve the following problems. Show your work and include the units

8.  How many moles is 9.3 x 1015 atoms of Pb?



9. How many representative particles are in 2.73 x 10-2 moles of MgI?



10. What is the molar mass of C2H6?



11. Find the mass of each of the following

          A. 3.65 x 10-2 mol K2SO4



          B. 2.61x 1022 molecules H2O2


          C. 0.60 mol CH4



          D. 0.70 L Kr a STP



12. What is the density of N2O gas at STP?



13. You have 3.8 grams of CO2. Convert that to:

          A. Moles



          B. Molecules



          C. Atoms



          D. Liters at STP



          E. Find the density



14. Determine the percent composition of CaSO4.





15. How many grams of calcium would there be in 25.3 g of CaSO4 ?



16. A compound is 43.2 % copper, 24.1 % chlorine and 32.7% oxygen. What is its empirical formula?






17. A gas is found to contain 78.1 % B and 21.9% H. It has a density of 1.23 g/L at STP. What is its

a.     empirical formula?

b.     molar mass?

c.      molecular formula?