1.         a.         9.0g/mole

            b.         2*26.98+3*16.00;

                                101.96g/mole

c.         >2*1.01;

                                 2.02g/mole

d.         > 6*12.01+6*1.01;

                                78.12g/mole

e.         > 2*12.01+4*1.01+2*16.00;

                                60.06g/mole

f.          > 63.55+2*14.01+6*16.00;

                                187.57g/mole

g.         > 131.3+195.09+6*19;

                                440.39g/mole

2.         a.         10g/(9.01*(g/mole));

                           1.1 moles

b.                     > 36g/(12.01*(g/mole));

                           3.0 moles

c.                     > 0.105mole*(23.00+16.00+1.01)*(g/mole);

                              4.2 g

d.                     > 1.0g/(18*(g/mole));

                          0.056 mole

e.                     > 0.56g/(187.57*(g/mole));

                          .002985552061 mole

f.                      > 750g/(28*(g/mole));

                           26.78571429 mole

3.         =120 moles *16 (g/mole) = 1920 g

4.         a.         2

b.                  2

c.                   1

5.         0.00010 = 1.0 X 10^-4 mole

1.0  X 10^-4 mole X 6.02 X 10²³ atoms/mole = 6.02 X 10¹⁹ atoms.

6.         Carbon consists of a mixture of isotopes. 12.011 is the weighted average of those isotopes’masses.

7.         0.2*g/(18*(g/mole))*(6.02*10^23)*(molecules/mole);

                     = 6.67 x 10²¹   molecules

8.         Find the molar mass for each of the following:

a.         He

4.0 g/mole

b.         Fe₂O₃  

2(56)+3(16) = 160 g/mole

c.         O₃  (ozone)

3(16) = 48 g/mole

d.         C₅H₅OH

5(12) +16 + 6(1) = 82 g/mole

e.         (NH₄)₂S

2(14) +8(1) + 32 = 68 g/mole

f.          Ca(NO₃)₂

40 + 2(14) + 6(16) = 164 g/mole

g.         Na₂SO₄

2(23) + 32 + 4(16) = 142 g/mole

9.         Convert the following:

a.         30 grams of C = __?__ moles

30g (mole/12 g) = 2.5 moles

b.         56 g of N= __?__ moles

56 g of N(mole/14 g) = 4.0 moles

c.         0.356 moles of NaNO₃ = __?__ grams

0.356 moles of NaNO₃(23 + 14 + 3(16) g/mole) = 30.3 g

d.         One gram of H₂O₂ = __?__ moles

1g (mole/34 g) = 0.029 moles

e.         100 g of Ca(NO₃)₂       =__?__ grams

100 g of Ca(NO₃)₂(mole/164g) = 0.61 moles

f.          0.750 g of O₂ = __?__ moles

0.750 g of O₂(mole/32g) = 0.023 moles

g.         One mole of copper= ___?___grams.

63.5 g

h.         2.0 moles of sodium phosphate = ___?___ grams

2.0 moles Na₃PO₄(2*23 +31+4*16) = 328 g

i.          2.58 g of potassium chloride = ___?___ moles

2.58 g KCl (mole/(39 + 35.5 g)) = 0.034 moles

10.       What is the mass, in grams, of 12.0 moles of C₃H₈?

12 moles (44g/mole) = 528 g

11.       What is the mass of a single molecule of He?

1  molecule(mole/6.02 X 10²³ molecules)= 1.66 X10^-24 moles

1.66 X10^-24 moles* (4 g/mole) = 6.64 X 10^-24 g