True / False
If the statement is True, write True. If the statement is False, correct the underlined word so it reads true.
1. Nitrogen dioxide and dinitrogen tetroxide have the same empirical formula.
2.
CH2 and C5H10 have the same empirical formula.
 
3.
One gram of sulfur contains 6.02 x 1023 atoms.
 
4.
The empirical formula of a compound gives the smallest ratio of the atoms that are present in the compound.
 
5. It is possible for two different compounds to have identical empirical formulas.
Multiple Choice
6.
When converting from grams to moles, you must ...
7.
When converting from moles to atoms or molecules, you must ...
8.
How many chlorine atoms are in 4.9 mol of PCl3
9.
How many grams of Au2S can be obtained from 8.66 mol of Au?
10.
What is the molar mass of Al(OH)3?
11.
White phosphorus is one of several forms of phosphorus and exists as a waxy solid consisting of P4 molecules. How many phosphorus atoms are present in 5.400 mole of P4?
12.
How many copper atoms are in 2.6 mol of the mineral chalcocite, Cu2S
13.
The number of moles in 65.0 g of acetylsalicylic acid (aspirin), C9H8O4, is
14. Which one of the following could be an empirical formula?
A.
C3H8
B.
C6H6O6
C.
C2H2Cl2
D.
C2H6
15. Which compound contains 35.0% N?
A.
NH4NO3
B.
NH4NO2
C.
NH4Cl
D.
NH2OH
E.
none of the above
16. Which compound has the lowest percentage of calcium?
A.
CaF2
B.
CaCl2
C.
CaBr2
D.
CaI2
17.
2.00 mol of CO2
A.
Have a mass of ? g
B.
Contain ? molecules
C.
Have a mass of ? g
D.
Contain ? molar masses of CO2
18.
In Ag2CO3, what is the percent by mass of each element?
19.
A compound contains 40.0% C, 6.7% H, and 53.3% O. The molar mass is 60.0 g/mol. The molecular formula is
20. Calcium sulfate is known to form a hydrated compound. When a 3.50 g sample of the hydrate is heated to dryness, the residue that remains has a mass of 2.77 grams. The formula of the hydrate is