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:
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?