H CH 8 HOMEWORK
Assign oxidation numbers to the following:
NaCl
MgBr2
SO2
Al
NO2-1
PO4-3
Na3BO3
Na3N
Ca(NO3)2
CBr4
KClO4
NH4+1
1. Distinguish between binary and ternary acids and give two examples of each.
2. What are monatomic ions?
3. In naming and writing formulas, what determines the order in which the elements
appear?
4. What are oxidation numbers?
1
Monatomic Ions:
O-2
Sulfide
Mg+2
Tin (II) ion
Fe+3
Barium ion
N-3
Fluoride
Ag+1
Copper (I) ion
Binary Molecular:
N2F2
Dinitrogen Monoxide
CI4
Phosphorous Trichloride
NO2
Pentabromine Dioxide
P3O4
Sulfur Mononitride
SCl2
Carbon Disulfide
Binary Ionic:
MgCl2
Nickel (II) Chloride
W2O3
Vanadium (III) Phosphide
ZnS
Silver Sulfide
AlF3
Potassium Chloride
Cd3P2
Calcium Selenide
FeN
Molybdenum (VI) Fluoride
Cs2 S
Cadmium Bromide
Y2O3
Manganese (II) Nitride
SnI4
Gold (I) Oxide
Cu3P2
Titanium (IV) Sulfide
2
Polyatomic Ionic:
NaNO3
Magnesium Borate
W PO4
Tin (IV) Sulfate
K2SO3
Calcium Bicarbonate
Mg(C2H3O2)2
Hydrogen Peroxide
Fe(BrO3)2
Sodium Azide
KMnO4
Lead (II) Tartrate
ZnCr2O7
Copper (II) Ortho-Silicate
Al2(CO3)3
Hydrogen Cyanide
Cd3[Fe(CN)6]2
Iridium (VI) Hydroxide
AgClO
Barium Nitrate
Acids:
HCl
Sulfuric Acid
HIO3
Hydrofluoric Acid
H2CO3
Sulfurous Acid
HBr
Oxalic Acid
3
Formula Writing:
potassium chlorate
__________
potassium chloride
__________
nickel (II) phosphide __________
stannic nitrite
__________
aluminum borate
__________
cobalt (III) sulfate
__________
cadmium sulfate
__________
ammonium carbonate __________
magnesium hydroxide__________
aluminum sulfite
__________
sodium bromide
__________
silver acetate
__________
zinc nitrate
__________
sulfur dioxide
__________
phosphoric acid
__________
ammonium chlorate __________
zinc sulfide
__________
potassium nitride
__________
gold (I) dichromate
__________
lead (IV) phosphate
__________
lead (II) iodate
__________
calcium acetate
__________
cupric phosphate
__________
lithium dichromate
__________
aluminum oxide
__________
potassium oxide
__________
hydrobromic acid
__________
ammonium hydroxide __________
barium hydroxide
__________
magnesium borate
__________
carbon tetrachloride __________
sodium dichromate
__________
nitrogen dioxide
__________
barium chlorate
__________
sodium bicarbonate
__________
carbonic acid
__________
calcium permanganate__________ citric acid
__________
lithium nitrite
zinc iodate
__________
cadmium perchlorate __________
barium chlorite
__________
manganese (II) oxide __________
magnesium nitride
__________
lithium borate
__________
cobalt (II) bisulfate
__________
hydroiodic acid
__________
ferrous phosphate
__________
carbon disulfide
__________
__________
dinitrogen pentoxide __________
4
Naming:
Pb3(PO4)2
__________
CoSO4
__________
CuSO4
__________
CuSO3
__________
Pb(ClO3)4
__________
H2SO4
__________
Fe(N3)3
__________
Fe2(SO4)3
__________
Cr(OH)2
__________
KBrO3
__________
Cd(IO3)2
__________
FeCO3
__________
CaCr2O7
__________
Ba(NO3)2
__________
KNO3
__________
NH4C2H3O2
__________
Pb3N2
__________
Ba3P2
__________
HCl
__________
SO3
__________
Mg(NO3)2
__________
HNO3
__________
Li2SO4
__________
(NH4)2CO3
__________
CuCrO4
__________
NaHCO3
__________
Ca(ClO2)2
__________
Ba(NO2)2
__________
Ag2CrO4
__________
Sn3(PO4)2
__________
HC7H5O2
__________
CaH2
__________
AuClO4
__________
Mg(OH)2
__________
KHSO4
__________
SrCl2
__________
MnS
__________
AgNO3
__________
P2O5
__________
FeHPO4
__________
PCl5
__________
HC2H3O2
__________
H3PO4
__________
N2O
__________
5
Make a correction, if necessary, and then provide the name/formula.
Correction
Name/Formula
Ba3NO3
KSO4
Mg3(PO4)2
BaCr2O7
NaC2H3O2
PbBr2
Ag2(CO3)2
NaHCO3
HSO4
NH4(NO2)2
Magnesium (II) hydroxide
Dilithium oxide
Fluoric acid
Calcium bicarbonate
Pb(II)SO4
6
Practice Quiz:
Formula:
Name:
Formula:
Name:
6. S-2
__________
2. chromium (III) ion__________
7. I-1
__________
3. yttrium ion __________
8. Fe+3
__________
4. nitride
__________
9. Ba+2
__________
5. chlorine
__________
10. O-2
__________
1. silver
__________
Provide Formulas:
11. sodium sulfate
12. copper (I) oxide
13. potassium chlorite
14. calcium phosphate
15. aluminum nitride
16. chromium (III) chloride
17. phosphorus trichloride
18. oxalic acid
19. barium phosphide
20. gold (I) fluoride
Provide Names:
21. P2O3
_________________________
26. Ni(ClO3)2 _________________________
22. SnCl2
_________________________
27. Pb3N4
_________________________
23. ZnS
_________________________
28. MgSO4
_________________________
24. NaOH
_________________________
29. HBr
_________________________
25. CuBr2
_________________________
30. K2O
_________________________
7
Calculate the Formula Mass of the following:
1. a. H2SO4
b. Fe(C2H3O2)2 (SF)
c. CaSO4  2H2O
2. Determine the formula mass for the following. (SF)
H OH O
| | |
H—C—C—C—O—H
|
H
3. Calculate the formula mass for acetylsalicylic acid:
Mole Calculations:
1. Calculate the mass of 2.00 mols of sulfuric acid.
2. Calculate the number of moles in 60.00 g of potassium carbonate (SF).
3. Calculate the number of molecules in 2.00 g of carbon dioxide.
4. Find the number of grams in 7.2434 x 1024 ions of lithium ions.
5. 3.45 x 1023 “molecules” of barium phosphate would contain how many atoms?
8
Composition Stoichiometry:
1. 23 g of manganese (III) sulfate would contain how many grams of manganese?
2. 77 g of phosphoric acid would contain how many mols of hydrogen?
3. 3.4 mols of zinc sulfite would contain how many grams of zinc?
4. 2.5 mols of calcium thiosulfate would contain how many mols of calcium?
5. 56.33 g of barium would be how many mols?
6. 657 g of sodium peroxide would contain how many mols of oxygen? (SF)
7. If a sample of iron (III) oxide contained 26 g of iron, what was the mass of the original
sample?
8. 45 g of oxygen would be how many mols?
9. 23 g of nitrogen dioxide would contain how many grams of oxygen? (SF)
10. The average person exhales 500 mols of carbon dioxide in a day. How many grams
of carbon would that be?
9
Calculate the Percent Composition of the following:
1a. Fe2O3
b. Ag2O
2. Determine the percent calcium in calcium phosphate.
3. For the compound sodium sulfate decahydrate, calculate the following:
a. %Na
b. %O
c. %H2O
4. Calculate the mass of the metal in each of the following:
a. 50 g of MgS
b. 25 g of FeCO3
c. 200.00 g of aluminum oxide (SF)
d. 10 g of copper (II) bromide
e. 50 g of lead (II) oxide which is 30% pure
f. 40 g of lead (IV) oxide which is 60% pure
5. The active ingredient in common household liquid bleach is the hypochlorite ion,
ClOa) Determine the percent of active ingredient in sodium hypochlorite.
b) If bleach contains a 5% solution of sodium hypochlorite by mass, calculate the
percentage of hypolchlorite ion in the bleach.
6. A sample of brass contains by mass 28.0% zinc and 72.0% copper. How many
kilograms of brass could be produced from 6.00 kilograms of copper?
7. A household detergent contains 35% sodium tripolyphosphate, Na5P8O10. This
complex salt keeps the pH of the wash water slightly basic by buffering action. The
tripolyphosphate can also form soluble complexes with hard water ions (Ca+2 and Mn+2)
that would otherwise form insoluble precipitates with detergent molecules. Determine
the percent of phosphorous in the detergent.
8. A bituminous coal sample had a mass of 20.0 g after complete drying. The coal’s
sulfur was chemically converted to the precipitate barium sulfate. If the mass of the dry
precipitate is 2.35 g, what was the percent sulfur in the dry coal?
10
Empirical and Molecular Formula Determination:
1. Calculate the empirical formula for the following compounds:
a. 63.1% Mn; 36.9% S
b. 26.6% K; 35.4% Cr; 38.0% O
2. Find the empirical formula for a compound given that a 48.5g sample is found to
contain 1.75g of carbon and 46.75g of bromine.
3. The formula mass of a compound is 92g/mol. Analysis shows that there are .608g of
nitrogen and 1.388g of oxygen. What is the molecular formula of the compound?
4. Determine the molecular formula of a compound that has a formula mass of 220 and is
56.4% phosphorus and 43.7% oxygen.
5. A 13.83 g sample of unknown decomposes when heated, giving CO2 (g) and 6.57g of
solid MgO. What is the empirical formula for the compound?
6. 1.62g of CoCl2  xH2O gave a residue of .88g. Find the formula of the hydrate.
7. 1.26g of CaSO4  xH2O gave a residue of .99g. Find the formula of the hydrate.
8. What is the molecular formula of a hydrated sodium salt which has a formula mass of
about 268g/mol and contains 46.9% water of hydration? An analysis reveals the
following composition: Na 17.18%, P 11.57%, H 5.60%, O 65.70%
9. A hydrate magnesium compound has a formula mass of about 174 g/mol and contains
31.0% water of hydration. From the following analysis, calculate the molecular formula:
Mg 13.90%, P 17.74%, H 4.01%, O 64.30%.
11
Practice Quiz 1:
1. Assign oxidation numbers to the following:
A. NO2-1
B. Fe2(SO4)3
2. Determine the formula mass of #1B.
3. 4 moles of carbon tetrachloride would contain how many moles of carbon?
4. If a sample of iron (III) oxide contained 2.5 moles of oxygen, then how many grams
of iron would be in it?
5. Find the percent composition of carbon tetrachloride.
6. Mass of crucible and contents before heating.
Mass of empty crucible.
Mass of crucible and contents after heating.
21.54g
19.82g
20.94g
Find the percent water in the sample.
Practice Quiz 2:
1. What are the empirical and molecular formulas of a compound if 212.1g of the
compound contains 42.4g of hydrogen and 169.7g of carbon. The formula mass of the
compound is 30.0 g/mol.
2. What is the formula mass of lithium phosphate?
3. How many grams of chromium are in 20g of chromium (II) chloride?
4. 3.56 x 1023 molecules of carbon dioxide would be how many grams?
5. 76g of copper (II) oxide would contain how many mols of copper and how many
moles of oxygen? Why are these numbers the same? Would there be 38 g of each?
Practice Quiz 3:
1. Assign oxidation numbers to the following:
A. IrS2
B. C2O4-2
2. What is the formula mass of sodium tetraborate?
3. 18.46g of copper (II) chloride would contain how many moles of chlorine?
4. Find the percent composition of diphosphorous pentoxide.
5. 11 moles of sulfuric acid would be how many grams?
7. Determine the molecular formula of a compound with a formula mass of 32 g/mol
which is 87.5% nitrogen and 12.5% hydrogen.
12
H Lab: Determination of Avogadro’s Number by Monolayer Film:
DATA:
Calibration of dropper:
How many drops are equal to 1mL
Diameter of monolayer film:
Trial #1:
Trial #2
Trial #3
Average
__________drops = 1cm3
__________drops = 1cm3
__________drops = 1cm3
__________drops = 1cm3
Measurement #1 = __________cm
Measurement #2 = __________cm
Measurement #3 = __________cm
Measurement #4 = __________cm
Average Diameter = __________cm
CALCULATIONS:
1. 1 drop of oleic acid solution is how many cm3?
1 drop = _______________cm3
2. Determine the volume of oleic acid in 1 drop. This is equal to the volume of the film
if it is truly monolayer. Remember, the drop is only .5% oleic acid.
1 drop = _______________cm3 of oleic acid
3. Using your average diameter, determine the area of the film in cm2.
A = _______________cm2
4. From the volume of oleic acid in a drop (#2) and the area of the monolayer film (#3),
calculate the thickness of the film (i.e. the height of the oleic acid molecule). Remember,
the volume of a cylinder = area x height
h = _______________cm
13
5. The oleic acid molecule, C17H33COOH, is 18 carbons in length and two hyrdogens are
attached to each carbon (see picture). Assuming the atoms are roughly the same
diameter, approximately how many times longer than wide/deep is the molecule?
width and depth = _________(fraction) of height
6. The oleic acid molecules orient themselves with the –COOH (carboxylic acid) group
attached to the surface of the water (why is that?). Using your answer from #4 and from
#5, and assuming that the oleic acid molecule is a rectangular solid, calculate the volume
of 1 molecule of oleic acid.
height = _______________ cm (#4)
width or depth = _________________ cm
(#5 x height)
Volume of Oleic Acid molecule (rectangular solid) = _______________ cm3/molecule
7. Using your answer from #6, determine the number of molecules/cm3.
______________molecules/cm3
8. Given that the density of oleic acid is .89 g/cm3 and using your answer from #7, find
the mass of 1 molecule of oleic acid.
mass = _______________g/molecule
9. Find Avogadro’s number by finding the formula mass for oleic acid and your answer
from #8.
Formula mass = _______________g/mole
Avogadro’s Number = _______________ molecules/mole
14
/20
H LAB: PERCENT WATER IN COPPER (II) SULFATE PENTAHYDRATE
1. Set up the ring stand and crucible.
2. Rinse out the crucible and dry it.
3. Strongly heat the crucible with the lid offset for 2 minutes.
4. After 2 minutes, place the lid back on the crucible and allow it to cool.
5. Mass the crucible.
6. Place the first sample in the crucible and remass.
7. With the lid off, heat the crucible and sample for 10 minutes.
8. After 10 minutes, place the lid back on the crucible and allow it to cool.
9. Remass the crucible.
10. Repeat the procedure with the second sample of different size. You do not need to
repeat the initial heating procedure (#2 - #4)
11. Determine the actual percent water in copper (II) sulfate pentahydrate and calculate
your percent error using an average value.
12. Gather data for the average percent water from the other groups and determine the
uncertainty.
15
Place all work on a separate piece of paper.
SAMPLE DATA TABLE:
Sample 1
Sample 2
Mass of empty crucible and cover
________
________
Mass of crucible, cover, and sample
________
________
Mass of sample
________
________
Mass of crucible, cover, and sample after heating
________
________
Mass lost (water lost)
________
________
Experimental percent water in sample
________
________
Average percent water in crystal
__________
Actual percent water
__________
Percent Error (no sig figs, use average)
__________
Uncertainty (no sig figs)
__________
16
/20
H LAB: Empirical Formula Determination
Procedure:
1. Wash a crucible and cover and dry it.
2. Strongly heat the crucible with the lid offset for 2 minutes. Allow it to cool and mass
it.
3. Mass out approximately 2.00 g of the unknown and add it to the crucible. Remass the
crucible to verify the mass.
4. Cover the crucible and heat it gently for 10 minutes.
5. After 10 minutes, remove the cover and heat strongly for 4 more minutes. (If the
cover sticks notify the instructor.)
6. After 4 minutes, turn off the gas and cover the crucible and allow it to return to room
temperature. Remass.
Data and Calculations:
1. Mass of empty crucible and cover
__________
2. Mass of crucible, cover, and contents before heating
__________
3. Mass of contents
__________
4. Mass of crucible, cover, and contents after heating
__________
5. Mass of potassium chloride produced
__________
6. Mass lost during heating (O driven off)
__________
7. Empirical formula for your compound.
17
/10
LAB: PERCENT COMPOSITION OF A PENNY
DAY 1:
1. Obtain a 1983 or later penny.
2. Using a triangular file, make 5 marks on the edge, evenly spaced and parallel to the
edge of the penny, so that the zinc is exposed.
3. Mass your penny.
4. Place 25 ml of concentrated hydrochloric acid in a clean beaker.
5. Place your penny in the beaker and place the beaker under the fume hood on a piece
of paper that has your name on it.
DAY 2:
6. Using forcipes, remove the copper from the hydrochloric acid and gently rinse off the
copper in the sink.
7. Dry and remass the penny.
8. Determine the percent composition of the penny. Watch sig figs.
18