CH115-1C Patterson SI
Worksheet 11
1. List the intermolecular forces that can be found between molecules and define them.
Hydrogen bonding—attraction between the H bound to either F, O, or N, and a lone pair on
one of those atoms
Dipole-Dipole—attraction between the – and + ends of two molecules
London Forces—small attraction that happens due to the presence of electrons
2. For the following molecules, draw the Lewis structure, state whether it is polar/nonpolar, and
list the intermolecular forces found in the molecules. Which would you expect to have the
strongest intermolecular forces?
Water has the strongest intermolecular forces because it has the most hydrogen bonding, dipole-dipole,
and London forces
a. H2O
polar, H-bonding, Dip-dip, London
d. OF2
polar, Dip-Dip, London
b. CH4
e. NH3
Polar, H-bonding, Dip-Dip, London
Nonpolar, London
f.
PH3
c. CHCl3
polar, Dip-Dip, London
Polar, Dip-Dip, London
CH115-1C Patterson SI
Worksheet 11
3. What is the molar mass of NO2?
N = 14.01 g/mol; O = 16.00 g/mol
1 (14.01) + 2 (16.00) = 46.01 g/mol
4. What is the molar mass of CuSO4 • 5H2O? (Also, what is the name of this molecule?)
Name: Copper (II) sulfate pentahydrate
Cu = 63.546 g/mol; S = 32.065 g/mol; O = 16.00 g/mol; H = 1.0079 g/mol
Count up how many of each atom: 1 Cu, 1 S, 9 O, 10 H
1(63.546) + 1(32.065) + 9(16.00) + 10 (1.0079) = 249.69 g/mol
5. How many moles are there 89 g of propane?
Propane is C3H8
C = 12.01 g/mol; H = 1.0079 g/mol
Molar mass of propane = 3(12.01) + 8(1.0079) = 44.11 g/mol
89 𝑔 𝐶3𝐻8 ×
1 𝑚𝑜𝑙 𝐶3𝐻8
𝑔
= 2.018
𝐶3𝐻8
44.1 𝑔
𝑚𝑜𝑙
With sig figs, the answer is 2.0 mol of C3H8
6. You met Avagadro at the bar last night and he gave you his number. What was it?
6.022 x 1023
7. How many liters of liquid ammonia do I have in 3.57 moles? (density = 1.023 g/mL at 25 °C)
Ammonia is NH3.
N = 14.01 g/mol; H = 1.0079 g/mol
Molar mass = 1 (14.01) + 3 (1.0079) = 17.0337 g/ mol
3.57 𝑚𝑜𝑙 𝑁𝐻3 ×
17.0337 𝑔
1 𝑚𝐿
1𝐿
×
×
= .059 𝐿 𝑜𝑓 𝑁𝐻3
1 𝑚𝑜𝑙
1.023 𝑔 1000 𝑚𝐿