Writing and naming binary compounds worksheet

Name ______________________________________ WKS 9.1 - Calculating Molar Mass (1 page)
Find the molar mass (AKA the molecular or formula mass) for each of the following substances.

Name of compound
Formula of compound
Molar Mass (g/mol)
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Name ______________________________________ WKS 9.2 - Calculating with Molar Mass (1 page)
PART A: MASS TO MOLES USING MOLAR MASS! (Remember: Molar Mass is the general term we use for atomic mass,
formula mass, and molecular mass - all in g/mol.) YOU MUST SHOW YOUR WORK USING DIMENSIONAL ANALYSIS
TO EARN CREDIT!!!
1. How many moles of nickel are are in 25 g of nickel? (0.43 mol)
2. What is the mass in grams of 1.25 moles of sulfur trioxide? (100. g)
3. How many moles of CaCO3 are present in a 350 g sample of CaCO3? (3.5 mol)
4. How many moles are there in 768 grams of iron (III) sulfate? (1.92 mol)


5. You have 13.2 moles of lead (II) nitrate. How many grams is this? (4.37 x 103 g)


PART B: CALCULATING MOLAR MASS! Use the formula for molar mass for your calculation. (MM = mass / moles)
YOU MUST SHOW YOUR WORK TO EARN CREDIT!

6. You have 0.51101 pounds of an unknown compound. It is known that this represents 4.5 moles of the compound. What is the
molecular mass of the compound? Hint: There are 454 grams in 1 pound. (51.56 g/mol)


7. What is the molecular mass of a compound if it is known that 658 grams of this compound represent 6.89 moles? (95.5 g/mol)


8. What is the molecular mass of a compound if 54.4 moles weighs 3.409 Kilograms? (62.7 g/mol)



9. If it is known that 41.6 grams of a pure, monatomic element represent 1.3 moles of the element, what is its atomic mass?
a. What element do you think it is? b. If this were known to be a diatomic element instead, what would you predict it to be? 90% of a worksheet must be completed to earn credit for that worksheet!
Name ______________________________________ WKS 9.3 - Calculating with Avogadro's Number (1 page)
YOU MUST SHOW YOUR WORK USING DIMENSIONAL ANALYSIS TO EARN CREDIT FOR THESE
PROBLEMS!
1. How many moles are represented by 8.27 x 1023 molecules of sodium chloride? (1.37 moles)


2. Aspirin, C9H8O4, is a commonly used pain killer. An average dose of aspirin in an aspirin tablet contains 2.775 x 10-3 moles of
aspirin. How many molecules does this represent? (1.671 x 1021 mlcl)


3. Magnesium sulfate is a salt commonly known as Epsom salts. Epsom salts are commonly used as soaking salts. How many
formula units are in 9.6 moles of Epsom salts? (5.8 x 1024 f.u.)

4. How many atoms are in 28 g of sodium? (7.3 x 1023 atoms Na)

5. How many molecules of chlorine gas are in a 150 g sample? (1.3 X 1024 mlcl Cl2)
6. Dioxin, C12H4Cl4O2 is a powerful poison. How many moles of dioxin are there in 700.0 g of dioxin? (2.174 mol)


7. One type of antibiotic, penicillin F, has the formula C14H20N2SO4. How many molecules of penicillin are there in a 250 mg dose
of penicillin? (4.8 x 1020 mlcl)


8. How many formula units would there be in a 54.3 gram sample of sodium nitrate? (3.85 x 1023 f.u.)


9. How much would 3.42 x 1023 formula units of mercury (II) oxide weigh in grams? (123g)


10. How many molecules are present in 0.00115 grams of carbon dioxide? (1.57 x 1019 molecules)
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Name ______________________________________ WKS 9.4 - Atoms Within Compounds (1 page)

These calculations use Avogadro's number, but you are trying to calculate to the count of atoms within a
compound. YOU MUST SHOW YOUR WORK USING DIMENSIONAL ANALYSIS TO EARN CREDIT FOR
THESE PROBLEMS!

1. How many oxygen atoms are in 163 g. of Al2(SO4)3? (3.44 x 1024 atoms O)



2. How many oxygen atoms are in a 235 g sample of oxygen gas? (8.84 x 1024 atoms O)


3. How many atoms of chlorine are in 0.20 mole of phosphorus trichloride? (3.6 x 1023 atoms Cl)


4. How many DIATOMIC MOLECULES of chlorine would there be in 28.0 grams of chlorine gas? (2.37 x 1023 molecules)
a. How many ATOMS of chlorine would be present in this same amount? (4.75 x 1023 atoms)

5. How many carbon atoms would there be in 200 grams of aluminum carbonate? (1.54 x 1024 atoms)
6. How many oxygen atoms are there in 170 grams of cesium phosphate? (8.29 x 1023 atoms)
7. If there are known to be 1.06 x 1024 oxygen atoms in a sample of barium permanganate, what is the mass of the entire sample of
barium permanganate in grams? (82.5 g)
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Name ______________________________________ WKS 9.5 - All Kinds of Compound Stoichiometry!!! (1 page)
These questions are combinations of all of the previous types. YOU MUST SHOW YOUR WORK USING
DIMENSIONAL ANALYSIS TO EARN CREDIT FOR THESE PROBLEMS!
1. If the molar mass of a substance is 203 g/mol, how many moles are there in 4567 milligrams of this substance? (2.25 x 10-2 mol)


2. How many moles are there in 78 grams of nitrogen gas? (2.8 mol)


3. How many atoms of copper are there in 1.00 kg of pure copper? (9.48 x 1023 atoms)

4. How many pounds would 5.75 moles of magnesium hydroxide weigh? There are 454 grams in 1 pound. (0.739 lb)


5. What is the molar mass of a compound if it is known that 8.00 X 108 micrograms of it represents 2.55 moles? (314 g/mol)


6. How many atoms of zinc are required to weigh 5.40 nanograms? (5.00 x 1013 atoms)


7. I have 3.45 x 1024 molecules of water.
a. How many moles are there in this amount of water? (5.73 moles)


b. How much would this weigh in pounds? (0.227 lbs)


8. If there are known to be 7.93 x 1024 atoms of oxygen present in a sample of magnesium sulfate, how much does the sample of magnesium sulfate weigh in pounds? There are 454 grams in 1 pound. (.870 lbs)

9. How many oxygen atoms are there in 2.4 pounds of calcium acetate? There are 454 grams in 1 pound. (1.7 x 1025 atoms)
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Name ______________________________________ WKS 9.6 - Percent Composition Problems (2 pages)
There are two types of percent composition problems - (1) Ones where you are calculating the mass percent of
elements, and (2) Ones where you are using the mass percent as a conversion factor within dimensional analysis.
YOU MUST SHOW YOUR WORK TO EARN CREDIT FOR THESE PROBLEMS!

1. Calculate the % mass of each element in ammonium nitrate. (N - 35.0 %, H - 5.0%, 0 - 60.0%)


2. Calculate the percent of each element in hydrogen phosphate. (H-3.1%, P-31.6%, O-65.3%)
3. Calculate the percent of each element in iron (III) oxide. (Fe = 70.0%, O = 30.0%)
4. Calculate the percent of each element in barium phosphate. (Ba = 68.4%, P = 10.3%, O= 21.3%)
5. For the hydrate sodium sulfate decahydrate, calculate the following:
a. The percent of sodium (by mass) in the hydrate (14.3%)
b. The percent of oxygen (by mass) in the hydrated compound. (Don't forget about the water!) (69.6%)
c. The percent of water (by mass) in the hydrate (55.9%)

6. Calculate the number of grams of magnesium in 50.0 g of magnesium sulfide. (21.6 g)

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Name ______________________________________ WKS 9.6 - Percent Composition Problems (continued)

7. Calculate the number of grams of iron in 80.0 kg of iron (II) carbonate. (3.86 x 104g)
8. Calculate the mass of aluminum (in kg) in 200. Kg of aluminum oxide. (0.106 Kg)

9. What mass of LEAD could be obtained from 50.0 grams of lead (II) oxide ore which is only 30.0% pure lead (II) oxide? (13.9 g)
10. What mass of iron could be obtained from 40.0 grams of iron (III) oxide ore which is only 75.00% pure iron (III) oxide? (21.0 g)
11. A sample of brass contains (by mass) 28.0% zinc and 72.0% copper. If you are a brass manufacturer and only have 68.0 kg of
copper and an unlimited supply of zinc, how many kg of brass could you produce? (94.4 kg)
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Name ______________________________________ WKS 9.7 - Empirical Formulas (1 page)
Find the empirical formula for each of the following problems. Remember your helpful saying… "percent to mass,
mass to mole, divide by the smallest, multiply until whole!". YOU MUST SHOW YOUR WORK TO EARN
CREDIT FOR THESE PROBLEMS!

1. What is the empirical formula for a compound which contains 0.0134 g of iron, 0.00769 g of sulfur and 0.0115 g of oxygen?
2. Find the empirical formula for a compound which contains 32.8% chromium and 67.2% chlorine. (CrCl3)
3. What is the empirical formula for a compound which contains 67.1% zinc and the rest is oxygen? (ZnO2)
4. Barry Um has a sample of a compound which weighs 200 grams and contains only carbon, hydrogen, oxygen and nitrogen. By
analysis, he finds that it contains 97.56 grams of carbon, 4.878 g of hydrogen, 52.03 grams of oxygen and 45.53 grams of
nitrogen. Find its empirical formula. (C5H3O2N2)
5. The characteristic odor of pineapple is due to ethyl butyrate, an organic compound which contains only carbon, hydrogen, and oxygen. If a sample of ethyl butyrate is known to contain 0.62069 g of carbon, 0.103448 g of hydrogen and 0.275862 g of
oxygen, what is the empirical formula for ethyl butyrate? (C3H6O)
6. 300 grams of an organic sample which contains only carbon, hydrogen and oxygen is analyzed and found to contain 145.946 grams of carbon, 24.3243 grams of hydrogen, and the rest is oxygen. What is the empirical formula for the compound?
(C3H6O2)
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Name ______________________________________ WKS 9.8 - Molecular Formulas and Hydrate Formulas (2 pages)
Find the formulas for each of the following problems. YOU MUST SHOW YOUR WORK TO EARN CREDIT
FOR THESE PROBLEMS!
1. What is the molecular formula of dichloroacetic acid if the empirical formula is CHOCl and the molecular mass is 128 g/mole? (C2H2O2Cl2)
2. What is the molecular formula of cyanuric chloride if the empirical formula is CClN and the molecular mass is known to be 184.5 g/mole? (C3Cl3N3)
3. Find the molecular formula of a compound containing three elements if it is known that 26.7% of the compound is phosphorus, 12.1% is nitrogen and the rest is chlorine. The molecular mass is 695 g/mole. (P6N6Cl12)
4. The ratio of carbon atoms to hydrogen atoms of oxygen atoms in a molecule of THC (the active ingredient in marijuana) is 11:15:1. The molecular mass of THC is 326 g/mole. What is the molecular formula for tetrahydrocannabinol, THC? (C22H30O2)
5. A chemist has a sample of hydrated Li2SiF6 and it weighs 0.4813 grams. He heats it strongly to drive off the water of hydration, and after heating, he found that the anhydrous compound has a mass of 0.391 grams. Find the formula of the hydrate.
(Li
6. A chemist has a sample of hydrated magnesium sulfite which weighs 1.50 grams. After heating it strongly, he finds that 0.763 grams of water have been driven off. Find the correct formula of the hydrate. (MgSO •6H
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Name ______________________________________ WKS 9.8 - Molecular Formulas and Hydrate Formulas (continued)
7. A chemist finds by experimentation that a certain compound contains 76.9% dry calcium sulfite and 23.1% water by weight in its crystal. What is the formula of the hydrate? (CaSO •2H
8. A chemist heats a sample of hydrated lithium nitrate which weighs 170 grams and finds, after heating that it weighs 95.3 grams. Find the correct formula of the hydrate.(LiNO •3H
9. A chemist heats a sample of barium bromide and finds that it gave off 10.8 grams of water. The compound which is left in the crucible after heating weighs 89.2 grams. What is the formula of the hydrate?(BaBr •2H
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