Chemistry 11

Mole Unit VI

 

Lesson                        Date                Topic                                                                           WS

 

1.                                             The Molar Mass                                                           1

 

2.                                             Mole Conversions                                                        2

 

3.                                             Calculating Atoms                                                         3

 

4.                                             Empirical Formula                                                         4

 

5.                                             Percentage Composition Empirical Formula                   5

 

6.                                             Mole Calculations to Molecular Formula                       6         

 

7.                                             Identify that Gas                                                           7

 

8.                                             Practice Test 1                                                             8

 

9.                                             Practice Test 2                                                             9


Worksheet # 1            Mole conversions

 

 

Describe each particle as an atom, molecule or a formula unit.

 

1.         CO2                                                               

2.         KCl                                                                

3.         C                                                                   

4.         AgNO3                                                          

5.         NH4CH3COO                                                

6.         O2                                                                  

7.         Os                                                                  

8.         SO3                                                                

9.         RbCl                                                              

10.       CaCO3                                                           

11.       Ag                                                                  

12.       NH3                                                               

13.       Cl2                                                                 

14.       Se                                                                  

 

 

 

15        The electrolysis of water using H2SO4 as a catalyst is used to generate hydrogen gas. For every 1 electron consumed 1 atom of hydrogen (exact) is generated. An amp meter is used to measure the rate of electron consumption.

 

            1.00 coulomb = 6.24 x 10 18 electrons.

 

            If 1.00 g of hydrogen is generated at a current of 1.50 amps (1 amp = 1 coulomb          per second) and over time period of 17.865 hours, calculate Avogadro’s number   (the number of atoms in 1.00g of hydrogen). Use unit analysis! Start the unit             analysis with 17.865 h and end with atoms H.

 

 

 

 

 

 

 

16.       State Avogadro's # three different ways describing the number of atoms in a mole, formula units in a mole, and molecules in a mole.

 

 

 

 

 

Use Unit Analysis to Change from particles to moles or from moles to particles. Note that a particle is an atom, molecule, or formula unit.

 

17.       Covert 5.44  x  1026 at Co to moles.

 

 

 

 

18.       Convert 2.4 moles CO2 to molecules.

 

 

 

 

19.       Covert 4.56  x  1024 molecules CO2 to moles.

 

 

 

 

20.       Convert 10.9 moles CuSO4 to FUs.

 

 

 

 

21.       Convert 5.33  x  1025 FU to moles NaCl.

 

 

 

 

22.       Convert 2.4 moles C to atoms.

 

 

 

 

23.       Covert 9.11  x  1025 molecules SO3 to moles.

 

 

 

 

24.       Convert 2.9 moles CaSO4 to FUs.

 

 

 

 

24.       Convert 5.55  x  1024 FU to moles KF.

 

Draw Electron-dot Diagrams for each of the following. Remember, use brackets for cations or anions. Covalent compounds do not require brackets.

 

 

25.       CCl4                                                                  26.       NaCl

 

 

 

 

 

 

 

27.       CO2                                                     28.       Li2SO4

 

 

 

 

 

 

 

 

29.       HCN                                                    30.       NO3-

 

 

 

 

 

 

 

 

Worksheet # 2                                    The Mole                   

 

 

Calculate the molar mass of the following compounds.  Remember to determine the mass of each element and add the mass of the elements together.

 

 

1.         KI                                                        2.         Mg3(PO4)2                                                 

3.         NiO                                                     4.         H2O                                                    

5.         BaF2                                                    6.         Ti(SO4)2.6H2O                                        

7.         CuS                                                     8.         ZnHCO3                                                     

9.         Li3N                                                     10.       PdSO4                                                         

11.       NaI                                                      12.       K3PO4                                                         

13.       FeO.6H2O                                           14.       NaOH                                                 

15.       AlF3.8H2O                                           16.       Ga2(CO3)3                                                 

17.       CuH2                                                    18.       Zn(CH3COO)2                                       

19.       NiN                                                     20.       BaSO4.5H2O                                       

 

Define the following. The first one is done for you.

 

21.       Atomic mass is the mass of 1 mole of atoms.

 

22.       Molecular mass is

 

23.       Formula mass is

 

24.       Molar mass is

                                               

 

25.       Describe as a formula unit, molecule, or atoms.

 

Au                    KCl                  NH4Cl              H2O                 CO2                 K         P2O5

 

Cu                    K2SO4             C                     NH3                 C12H24O11        NaCl    Br

 

Convert from grams to moles. Show all work using unit analysis.

 

26.      100. g H2O

 

 

 

 

27.       250. g MgCl2

 

 

 

28.       0.266 g C6H12

 

 

 

 

29.       1.2 x 10-4 g Fe

 

 

 

 

Convert each quantity to moles.

 

 

30.       500. g H2O     

 

 

 

 

31.       0.269 g P2O5

 

 

 

 

32.       135.3 g CaSO4

 

 

 

 

33.       214.7 g CH4

 

 

 

 

34.       25.3 g C6H12O6

 

 

 

 

 

 

 

 

 

Convert from atoms, molecules, or formula units to grams.

 

35.      6.55 x 1024 atoms Ag

 

 

 

 

 

36.      8.66 x 1026 FU RbCl

 

 

 

 

 

 

37.      5.00 x 10 32 molecules N2H4

 

 

 

 

 

38.       5.3 x 1029 FU KBr

 

 

 

 

39.        25.3 x 1028 molecules C4H10

 

 

 

 

40.      1.33 x 1025 atoms Ag

 

 

 

 

 

41.      1.55 x 1016 FU NaCl

 

 

 

 

 

42.      2.55 x 10 27 molecules NH3

 

 

 

43.       5.3 x 1029 FU KBr

 

 

 

 

 

Convert from grams to atoms, molecules, or formula units.

 

44.      100. g H2O2

 

 

 

 

45.      2.6 g MgF2     

 

 

 

 

46.       0.211 g C5H12

 

 

 

 

47.      3.33 x 10-2 g Fe

 

 

 

 

48.       0.126 g  Co

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Worksheet #3             Calculating Atoms and Molecules   

 

1.         Measure the mass some Calcium. Calculate the number of atoms. Add 50 mL water to a 250 mL fleaker. Add the calcium to the beaker and cover with a plastic funnel. Light the funnel after about 8 seconds. What gas is produced by the reaction?

 

 

 

 

 

2.         Measure the mass of a Copper cylinder. Calculate the number of atoms in the    cylinder.

 

 

 

 

 

 

3.         Measure the mass of an Iron cylinder. Calculate the number of atoms in the        cylinder.

 

 

 

 

 

 

4.         Measure the mass of a Magnesium cylinder. Calculate the number of atoms in the          cylinder.

 

 

 

 

 

 

5.         Measure the mass of an Aluminum cylinder. Calculate the number of atoms in the           cylinder.

 

 

 

 

 

6.         Measure the mass of a small amount of dry ice (be quick- it won’t last long due to         sublimation). Calculate the number of molecules of CO2.

 

 

 

7.         Calculate the mass of 4.56 x 1025 atoms of Sr.

 

 

 

 

 

8.         Calculate the mass of 6.33 x 1020 molecules of CO2.

 

 

 

 

 

9.         Calculate the mass of 8.66 x 1026 FU of SrO.

 

 

 

 

 

10.       Calculate the mass of 2.3 x 1028 FU of SrCO3.H2O.

 

 

 

 

 

11.       Calculate the number of H atoms in 5.02 g of CH4. There are 4 atoms of H in one         molecule of CH4.

 

 

 

 

 

12.       Calculate the number of O atoms in 200. g Al2(SO4)3. There are 12 atoms of O in         one formula unit of Al2(SO4)3.

 

 

 

 

 

13.       Calculate the mass of CaCO3 that contains 2.00 x 1028 atoms of O. There are 3            atoms of O per one FU of CaCO3.

 

 

 

 

 

14.       Calculate the mass of Al2(SO4)3 that contains 2.00 x 1028 atoms of O.

 

 

 

 

 

 

15.       Calculate the mass of Al2(SO4)3 that contains 2.00 x 1020 atoms of Al.

 

 

 

 

 

 

16.       Calculate the number of Al atoms in 500. g Al2(SO4)3.

 

 

 

 

 

 

 

 

 

 

Draw Electron-dot Diagrams for each of the following. Remember, use brackets for cations or anions. Covalent compounds do not require brackets.

 

17.       C2F6                                                                  18.       KClO4

 

 

 

 

 

 

19.       NH3                                                     20.       Li2CO3

 

 

 

 

 

21.       N2                                                        22.       PO33-

 

 

 

Worksheet #4             Empirical Formula

 

Use a calculation to determine the empirical formula of each of the following compounds. Show all of your work.

 

1.         A compound is found to be 6.353 g Ag, 0.823 g N, and 2.824 g of O. Calculate           the empirical formula of the compound.

 

 

 

 

 

 

 

 

2.         A compound is found to be 6.25 g Pb, 0.846 g N, and 2.90 g of O. Calculate the         empirical formula of the above compound.

 

 

 

 

 

3.         A compound is found to be 1.00 g Ca, 0.700 g N, and 2.40 g O.  Calculate the            empirical formula of the above compound.

 

 

 

 

 

 

 

 

 

4.         A compound is found to be 27.91 % Fe, 24.08 % S, and 48.0 % O. Calculate the        empirical formula.

 

 

 

 

 

 

 

5.         A compound is found to be 15.38 % Co, 40.74 % Cr, and 43.88 % O. Calculate         the empirical formula.

 

 

 

 

6.         A compound is found to be 63.65 % C, 10.71 % H, 18.56 % N, and 7.072 % O.        Calculate the empirical formula.

 

 

 

 

 

 

7.         Change 5.0 x 1026 formula units CoCl2. 6H2O to grams.

 

 

 

 

 

 

8.         Convert 2.36 g FeSO4·5H2O to formula units.

 

 

 

 

 

 

9.         Change 3.65 x 1022 molecules CO2 to grams.

 

 

 

 

 

 

10.       Convert 2.36 g grams P2O5 to molecules.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Worksheet # 5            Percentage Composition, Molecular and Empirical Formula

 

 

Complete the following chart.

 

Empirical Formula                     Molar Mass                  Molecular Formula       Molecular

                                                                                                                        Mass                 

 

1. CH                                                                                                               78 g/mole

 

 

2.  C3H2O                                                                                                        162.06 g/mole

 

3.                                                                                 C12H21N3O3                                                                                              

 

4.  C4H8O                                                                                                        216 g/mole

 

5.  C2H4NO                                                                                                     174 g/mole

 

6.                                                                                 C15H33N3O3                                        

 

7.  C2H2O                                                                                                        210 g/mole

 

8.  C3H7NO                                                                                                     292 g/mole

 

9.                                                                                 C4H8N2O2                                           

 

10.  CCl3                                                                                                          237 g/mole

 

 

 

11.       If the empirical formula for a compound is C2H3O and its molecular mass is 129            g/mole, what is the molecular formula.

 

 

 

 

 

 

12.       A compound is 49.2% P and 50.8% O, calculate the empirical formula. If the    molecular mass is 126 g/mole, calculate the molecular formula.

 

 

 

 

 

13.       A compound is 62.54 % Pb, 8.46 % N, and 29.0 % O, calculate the empirical formula.

 

 

 

 

 

 

 

 

 

 

 

 

14.       A compound is 46.08 % C, 27.0 % N, and 27.0 % O.  Calculate the empirical             formula. If the molecular mass is 832 g/mole, calculate the molecular formula.

 

 

 

 

 

 

      

 

 

 

 

 

 

 

 

15.       Oil of citronella is a mosquito repellent is 87.8% C and 12.2% H.  Calculate the            empirical formula. If the molecular mass is 205 g/mole, calculate the molecular    formula.

 

 

 

 

 

 

 

 

 

 

 

 

Calculate the percentage composition for:

 

16.       ZnSO4

 

 

 

 

 

17.       Al2(CO3)3

 

 

 

 

 

 

18.       Ca3(PO4)2

 

 

 

 

 

 

19.       Convert 3.66 kg CO2 to molecules.

 

 

 

 

20.       Covert 4.0 x 1026 FU of MgCl2 to Kg.

 

 

 

 

 

21.       In a propane tank there are 9.0 Kg of C3H8, calculate the number of H atoms.   (First calculate molecules and then H atoms).

 

 

 

 

 

 

 

22.       A certain mass of complex Co(NH3)6Cl3 was found to contain 2.65  x  1021 atoms        of H, calculate the mass of cobalt III chloride hexammine. (Change the number of   atoms to FU’s first).

 

 

Worksheet # 6            Mole Calculations to Molecular Formula

 

1.         Convert 500. g NaCl to formula units.

 

 

 

 

 

 

2.         Convert 9.8x1024 molecules of C2H6 to grams.

 

 

 

 

 

 

 

3.         Calculate the number of O atoms in 50.0 lb of dry ice CO2.

            (2.21 lb = 1.00Kg)

 

 

 

 

 

 

 

 

 

4.         Calculate the percentage composition of Al2(SO4)3.  3 significant figures!

 

 

 

 

 

 

 

 

 

 

5.         Calculate the molar mass of Co2(SO4)3 . 6H2O

 

 

 

 

 

 

6.         The empirical formula for a compound is C2H5O and its molecular mass is         135 g/mol.  The molecular formula is:

 

 

 

 

 

7.         A compound is 24.4 % Ca, 17.1 % N and 58.5 % 0.  Calculate the empirical   formula.

 

 

 

 

 

 

 

 

8.         Hydroquinone, a chemical used for photographic developing, is 65.45 % C,

            5.51 % H and 29.09 % O.  Calculate the empirical and molecular formula.  The            molecular mass is 110g/mol.

 

 

 

 

 

 

 

9.         A compound is 50.5 % C, 5.26 % H, and 44.2 % N, calculate the empirical formula. If the molecular mass is 380.2 g / mole, calculate the molecular formula.

 

 

 

 

 

 

 

10.       A compound is 50.5 % C, 5.26 % H, and 44.2 % N, calculate the empirical formula. If the molecular mass is 285.15 g/mole, what is the molecular formula?

 

           

 

 

 

 

Challenge Problems

 

11.       When 15.0 g of a compound known to contain C, H, O, and S was burned, 16.2 g       of CO2, 6.63 g of H2O, and 15.7 g of SO2 were produced. What is the empirical     formula of the compound?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

12.       When 51.3 g of a compound known to contain C, H, N, and O was burned, 84.2 g      of CO2, 20.7 g of H2O, and 10.7 g of N2 were produced. What is the empirical        formula of the compound?

 

 

 

 

 

 

 

 

Worksheet #7                         Identify that Gas                                                                   

 

1.         A volume of a gas weighs 0.256 g. An equal volume of H2 weighs 0.01163 g.    Calculate the molecular mass of the gas. Assuming that this gas is a common gas,     what do you think the gas could be? Show some work!

 

 

 

 

 

 

2.         A volume of a gas weighs 2.12 g. An equal volume of He weighs 0.265 g.         Calculate the molecular mass of the gas. Assuming that this gas is a common gas,     what do you think the gas could be? Show some work!

 

 

 

3.         A volume of a gas weighs 0.235 g. An equal volume of He weighs 0.02043 g.   Calculate the molecular mass of the gas. This gas is a gas produced by automobile   pollution, what do you think the gas could be? Show some work!

 

 

 

 

 

 

4.         A volume of a gas weighs 0.37216 g. An equal volume of H2 weighs 0.01163 g.            Calculate the molecular mass of the gas. Assuming that this gas is a on that is      produced by burning matches, what do you think the gas could be? Show some      work!

 

 

 

 

 

 

5.         A volume of a gas weighs 0.02051g. An equal volume of CO2 weighs .02654 g.            Calculate the molecular mass of the gas. Assuming that this gas is a smelly one   that is produced by rotten eggs, what do you think the gas could be? Show some      work! This gas is also added to natural gas to make it smell so that leaks can be             detected.

 

                       

 

6.         Convert 1.65 g CO2 to molecules.

 

 

 

 

 

7.         Convert 12.5 Kg of SO2 to molecules.

 

 

 

 

 

 

 

8.         Covert 2.0 x 1026 FU of MgCl2 to g.

 

 

 

 

9.         In a propane tank there are 8.0 Kg of C3H8. Calculate the number of H atoms. (First calculate molecules and then H atoms).

 

 

 

 

 

 

 

 

10.       A certain mass of complex Co(NH3)6Cl3 was found to contain 2.65  x  1025 FU,           calculate the mass of cobalt III chloride hexammine.

 

 

 

 

 

 

11.       The empirical formula of a compound is C3H11O3 and its molecular mass is        380.44 g/mole. Determine the molecular formula.

           

 

 

 

 

12.       Calculate the percentage composition of Co(NH3)6Cl3  to three significant          figures.

 

 

 

 

 

 

13.       A compound is 27.73 % Mg, 23.58 % P, and 48.69 % O, calculate the empirical         formula.

 

 

 

 

 

 

 

 

 

 

14.       9, 10-diehydro-6-methylergoline-8-carboxylic acid (LSD) a drug with   psychomimetric properties is 71.6 % C, 6.03 % H, 10.4 % N, and 11.9 % O. If the      molecular mass of the compound is 268.16 g/mol, calculate the empirical and the             molecular formula.

 

 

 

 

 

 

 

 

 

 

 

15.       A volume of a gas containing sulphur and oxygen that is produced by burning     coal has a mass of 2.088 g. An equal volume of H2 has a mass of 0.0658 g.      Calculate the molar mass of the gas and determine its formula.

 

 

 

 

 

 

 

 

16.       Here is the tough one. You can do it- just take it one step at a time!

 

            A compound was known to contain C, H, N, O, and S. When a 5.43g sample was       burned the products were 8.43 g CO2, 1.15 g H2O, 0.450 g N2, and 3.07 g of SO2.         Determine the empirical formula of the compound. I left you a whole page- I hope    that’s enough. Good luck!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Worksheet #8             Review of Mole Calculations

 

1.         Convert 2.59 g of SO3  to molecules.

 

 

 

 

2.         Convert 3.56 x 1025 FU  of  CoCl4 to Kg.

 

 

 

 

3.         In a propane tank there are 26.5 Kg. of C2H6. Calculate the number of H          atoms.

 

 

 

 

 

4.         Describe each atom as an atom, molecule, anion, cation, or a formula unit:

                       

CO2                                                    

                        Co                                                      

                        AgNO3                                                   

                        KCl   ­­­­­                                                  

                        Cr2O72-                                                    

                        NH4+                                                   

 

 

5.         Convert 568 g of H3PO4  to moles.

 

 

 

 

 

6.         Convert 3.25 x 105g Rh into atoms.

 

 

 

 

7.         Calculate the molar mass of the following compounds:

 

            Hg3(PO4)2                                                                           CuI2

 

            Pb2SO4                                                                                Li2SO3

 

8.         What is the percent composition of C2H6

 

 

 

 

 

 

 

9.         What is the percent composition of CaCl2. 2H2O

 

 

 

 

 

 

 

10.       The empirical formula of a compound is SiH3.  If 0.0275 mol of the compound has a mass of 1.71 g, what is the compounds molecular formula?

 

 

 

 

 

 

11.       A compound is 27.73% Mg, 23.58% P, and 48.69% O, calculate the empirical formula.

 

 

 

 

 

 

 

 

 

 

 

12.       Find the empirical formula for a compound containing 46.3 % Li and 53.7 % O.

 

 

 

 

 

13.       Convert 5.65  x 1017 atoms of Fe into grams.

 

14.       A compound contains C, H and O.  A 5.90 g sample is burned to yield 11.18 g of         CO2 and 3.66 g H2O.  What is the empirical formula of the compound?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

15.       A volume of a gas weighs 2.12 g.  An equal volume of He weighs 0.265 g.        Calculate the molecular mass of the gas.  Assuming that this gas is a common           diatomic gas, what do you think the gas could be?  Show your work.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Worksheet #9             Moles Practice Test  1

 

 

1.         Convert 5.65 g of SO2 to molecules.

 

 

 

 

 

 

2.         Convert 3.56 x 1025 FU of CuCl2 to Kg.

 

 

 

 

 

 

3.         In a lighter there are 0.52 g. of C4H10. Calculate the number of H atoms.

 

 

 

 

 

 

4.         Describe each atom as an atom, molecule, or a formula unit:

                       

            CO2                 ____________

                        Zn                    _____________

                        Ca(NO3) 2          _____________

                        NaCl  ­­­­­               _____________

                        CH3COOH        _____________

 

 

 

5.         Convert 572 g of HNO2 to moles.

 

 

 

 

 

6.         Convert 3.25 x 105 g Ru into atoms.

 

 

 

 

 

7.         Calculate the molar mass of the following compounds:

 

 

            Au3(PO4)3                                                                           CuBr2

 

 

 

            Pb3 (PO4) 2                                                                         Li2CO3

 

                       

 

8.         What is the percent composition of C3H10

 

 

 

 

 

 

 

 

9.         What is the percent composition of SrCl2 .3H2O

 

 

 

 

 

 

 

 

 

10.       The empirical formula of a compound is C3H8.  If 2.00 mol of the compound     has a mass of 264.48 g, what is the compounds molecular formula? Hint: first           calculate the molar mass by dividing grams by moles.

 

 

 

 

 

 

 

11.       Find the empirical formula for a compound containing 24.45  % Ca, 17.07  % N                       and 58.53 % O.

 

 

 

 

12.       Find the empirical formula for a compound containing 74.40  % Ga and

            25.60  % O.

 

 

 

 

 

 

13.       Convert 5.55 x 1017 atoms of Co into grams.

 

 

 

 

14.       A volume of a gas weighs 3.0475 g.  An equal volume of He weighs 0.265 g.    Calculate the molecular mass of the gas.  Assuming that this gas causes acid rain,     what do you think the gas could be?  Show your work.

 

 

 

 

 

 

 

15.       Methamphetamine, MDMA, or commonly called ecstasy is an illegal drug from a family called “entactogens”; which literally means in Greek, “touching within”.         This drug is considered to be a mood elevator that is:

            59.506 % C, 8.0135 % H, 6.9424 %   N, 7.934 % O, and 17.604 % Cl. Calculate      the empirical formula for MDMA.

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
16.       Brodifacoum, a Coumarin derivative used to poison rats, is also used a blood    thinner in small doses. An antidote for this poison is vitamin K, a blood-clotting      agent. This compound contains C, H, Br and O.  A 10.00 g sample is burned to          yield 25.633 g of CO2, 3.894 g H2O, and 1.502 g of Br2.  What is the empirical            formula of the             compound? The structural formula is shown below.
 

            STRUCTURAL FORMULA 1