1. Review Game
MOLES MOLES MOLES

2. What is the percent of Silver in Silver (I) Nitrate?
Percent Composition
What is the percent of Silver in Silver (I) Nitrate?
AgNO3 = (3) = 170
% Ag = 108/170 x 100 = 63.5%
63.5 % % 3. H 6.7% C 40% O 53.3% % N 74.1%O 5. Carb 3.2% Nit 1.59 %

3. What is the percent of Sodium in Sodium Carbonate?
Percent Composition
What is the percent of Sodium in Sodium Carbonate?
Na2CO3 = 2(23) (16) = 106
% Na = 2(23)/106 x 100 = 43.4 %

4. What is the percent composition of all elements in HC2H3O2?
%H = 4/60 x 100 = 6.67%
%C = 2(12)/60 x 100 = 40%
%O = 2(16)/60 x 100 = %

5. Percent Composition
What is the percent, by weight, of the elements in dinitrogen pentoxide?
N2O5 = 2(14) + 5(16) = 108
%N = 28/108 x 100 = 25.9%
%O = 80/108 x 100 = 74.1%

6. Percent Composition
Which has a higher percentage of hydrogen, carbonic acid or nitric acid?
Carbonic Acid = H2CO3 = 2(1) (16) = 62
2/62 x 100 = 3.23%
Nitric Acid = HNO3 = (16) = 63
1/63 x 100 = 1.59%
ANSWER: CARBONIC ACID

7. 4.56 grams of Zinc (II) Phosphate is equal to how many moles?
Mole Conversions
4.56 grams of Zinc (II) Phosphate is equal to how many moles?
4.56 g Zn3(PO4)2 / 385 = moles

8. 29.86 grams of Barium Carbonate is equal to how many moles?
Mole Conversions
29.86 grams of Barium Carbonate is equal to how many moles?
29.86 g BaCO3 / 197 = moles

9. 4.96 moles of Potassium Hydroxide is equal to how many grams?
Mole Conversions
4.96 moles of Potassium Hydroxide is equal to how many grams?
4.96 moles KOH x 56 = 278 g

10. 0.98 moles of Aluminum Nitrate is equal to how many grams?
Mole Conversions
0.98 moles of Aluminum Nitrate is equal to how many grams?
0.98 moles Al(NO3)3 x 213 = 210 g

11. 6.59 x 1023 molecules of CO2 is equal to how many moles?
Mole Conversions
6.59 x 1023 molecules of CO2 is equal to how many moles?
6.59 x 1023 molecules / 6.02 x 1023 = 1.09 moles

12. 9.85 x 1023 formula units of KCl is equal to how many moles?
Mole Conversions
9.85 x 1023 formula units of KCl is equal to how many moles?
9.85 x 1023 for u / 6.02 x 1023 = 1.64 moles

13. 0.23 moles of calcium is equal to how many atoms?
Mole Conversions
0.23 moles of calcium is equal to how many atoms?
0.23 moles Ca x 6.02 x 1023 = 1.4 x 1023 atoms

14. 1.25 moles of Cadmium Chloride is equal to how many formula units?
Mole Conversions
1.25 moles of Cadmium Chloride is equal to how many formula units?
1.25 moles CdCl2 x 6.02 x 1023 = x 1023 for u

15. 56.8 L of nitrogen gas is equal to how many moles at STP?
Mole Conversions
56.8 L of nitrogen gas is equal to how many moles at STP?
56.8 L N2 / 22.4 = 2.54 moles

16. 25.9 L of oxygen gas is equal to how many moles at STP?
Mole Conversions
25.9 L of oxygen gas is equal to how many moles at STP?
25.9 L O2 / 22.4 = 1.16 moles

17. 1.96 x 1023 molecules of CO2 is equal to how many liters at STP?
Mole Conversions
1.96 x 1023 molecules of CO2 is equal to how many liters at STP?
1.96 x 1023 molecules CO2 / 6.02 x 1023 x 22.4 = 7.29 L

18. What is the volume of 0.75 moles of He at STP?
Mole Conversions
What is the volume of 0.75 moles of He at STP?
0.75 moles He x 22.4 = 17L

19. What is the mass of 1.02 x 1023 molecules of xenon trichloride?
Mole Conversions
What is the mass of 1.02 x 1023 molecules of xenon trichloride?
1.02 x 1023 molecules XeCl3 / 6.02 x 1023 x 236 = 39.9g

20. What is the volume of 2.56 grams of chlorine gas at STP?
Mole Conversions
What is the volume of 2.56 grams of chlorine gas at STP?
2.56 g Cl2 / 71 x 22.4 = L

21. How many formula units are present in 5.8 grams of Calcium hydroxide?
Mole Conversions
How many formula units are present in 5.8 grams of Calcium hydroxide?
5.8 g Ca(OH)2 / 74 x 6.02 x 1023 = 4.7 x 1022 for u

22. What is the mass of 58.3 L of Argon gas, at STP?
Mole Conversions
What is the mass of 58.3 L of Argon gas, at STP?
58.3 L Ar / 22.4 x 40 = 104 g

23. Empirical and Molecular Formulas
A compound is 85.7% C and 14.3 % H. Determine the molecular formula if the molar mass is 70 g/mol.
85.7 g C / 12 = / = 1
14.3 g H / 1 = 14.3 / = 2
Empirical Formula = CH2 = 14
70/14 = 5
Molecular Formula = C5H10
1. C3H4O3 C6H8O CH2 C5H C4H9 C8H18

24. Empirical and Molecular Formulas
A compound is 41% C, 4.5 % H, and 54.5% O. Calculate the molecular formula if the molar mass is 176 g/mol.
41 g C / 12 = / = 1 x 3 = 3
4.5 g H / 1 = 4.5 / = 1.33 = 4/3 x 3 = 4
54.5 g O / 16 = / = 1 x 3 = 3
Empirical Formula C3H4O3 = 88
176/88 = 2
Molecular Formula C6H8O6
1. C3H4O3 C6H8O CH2 C5H C4H9 C8H18

25. Empirical and Molecular Formulas
Octane contains % C and % H and has a molar mass of g/mol. Determine the empirical and molecular formulas.
g C / 12 = / = 1 x 4 = 4
g H / 1 = / = 2.25 = 9/4 x 4 = 9
Empirical Formula = C4H9 = 57
/ 57 = 2
C8H18
1. C3H4O3 C6H8O CH2 C5H C4H9 C8H18

26. Calculate the percent of water in sodium sulfate decahydrate
Hydrates
Calculate the percent of water in sodium sulfate decahydrate
Na2SO4 . 10H2O = 2(23) + 1(32) + 4(16) + 10(18) = 322
% H2O = 18(10)/322 x 100 = 55.9%
% H2O % H2O %

27. Hydrates
A 1.62 gram sample of CoCl2 hydrate was heated. The anhydrous salt has a mass of 0.88g. Calculate the percent water and the formula of the hydrate.
Mass water = 1.62 – 0.88 = 0.74 g
0.88 g CoCl2 / 130 = / = 1
0.74 g H2O / 18 = / = 6
CoCl2 . 6H2O
% water = mass water / mass hydrate x 100 = 0.74 / 1.62 x 100 = 46 %
% H2O % H2O %

28. Hydrates
A 1.21 g Pb (C2H3O2) 2 hydrate was heated. The salt left over had a mass of 1.04g. Calculate the percent water and the formula of the hydrate.
Mass water = 1.21 – 1.04 = 0.17g
1.04 g Pb(C2H3O2)2 / 325 = / = 1
0.17 g H2O / 18 = / = 3
Pb(C2H3O2)2 . 3H2O
% Water = 0.17 / 1.21 x 100 = 14.1 %
% H2O % H2O %

29. I have 450 grams of hydronitric acid. How many atoms are present?
More Problems
I have 450 grams of hydronitric acid. How many atoms are present?
450 g H3N / 17 x 6.02 x 1023 x 4 = 6.4 x 1025 atoms

30. More problems
If a sample of dinitrogen pentoxide has 4.5 x 1024 atoms, how many liters are present?
4.5 x 1024 atoms N2O5 x (1 molecule/7 atoms) x (1 mol/6.02 x1023 molecules) x 22.4 = 24 L

31. Hydrate
I have 40 grams of a sodium phosphate hydrate. It loses 46.8% of its mass upon heating. What is the formula of the hydrate?
0.468 x 40 = grams water
40 – = grams anhydrous
18.72g H2O/18 = 1.04/ = 8
21.28g Na3PO4 / 164 = / = 1
Na3PO4 . 8H2O

32. Hydrate
The percent water in a 20.0 gram sample of potassium nitrate hydrate is 41.6%. What is the formula of the hydrate?
.416 x 20 = 8.32 grams H2O / 18 = / = 4
20 – 8.32 = grams KNO3/101 = / = 1
KNO3.4H2O

33. Hydrate
When 14.7 grams of a titanium (IV) nitrate hydrate is heated, 1.59 grams of mass is lost. What is the percent water, formula and name of hydrate?
14.7 – 1.59 = grams
13.11 grams Ti(NO3)4 / 296 = / = 1
1.59 grams H2O / 18 = / = 2
Ti(NO3)4 . 2H2O Titanium (IV) nitrate dihydrate
% water = 1.59/14.7 x 100 = 10.8 %