Topic 4.3.1 Questions
Intermolecular Forces and their affect on boiling point
1.
(N00/S)
a)
Draw the molecular shape of aminomethane, CH3NH2 and predict the bond angles
around the carbon and nitrogen atoms used the VSEPR theory. [4]
b)
Aminomethane, CH3NH2 and ethane have similar molar masses. Explain why
aminomethane has a boiling point of -6°C whereas that of ethane is -89°C. [4]
2.
(N04/S)
3.
(M03/H)
a)
b)
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Explain the trend in boiling points for H2S to H2Te. [2]
Explain why the boiling point of water is higher than would be expected from the group
trend. [2]
4.
(M00/H) Select the substance with the higher boiling point in each of the following pairs.
Explain your reasoning.
a)
C2H6 and C3H8 [3]
CH3CH2OH and CH3OCH3
[3]
b)
5.
(M02/H) Describe the bonding between the molecules in liquid fluorine. [2]
6.
(M04/S) Identify the strongest type of intermolecular force in each of the following molecules.
[3]
a)
CH3Cl
b)
CH4
c)
CH3OH
7.
(M04/H)
a)
List the following substances in order of increasing boiling point (lowest first) [2]
CH3CHO
b)
8.
C2H6
CH3COOH
CH3CH2OH
State whether each molecule is polar or non-polar, and explain the order of boiling
points. [6]
IB HL ONLY Ethanoic acid, CH3COOH molecules form dimers in non polar solvents.
a)
Draw the structural formula for ethanoic acid and determine its relative molecular mass.
b)
Draw the structural formula of the dimer and determine its relative molecular mass.
Label the intermolecular hydrogen bonds and the intramolecular covalent bonds.
Bibliography
Derry, Lanna, Maria Connor and Carol Jordan. Chemistry for use for the IB Diploma Standard level. Melbourne:
Pearson Education, 2008.
Organisation, International Baccalaureate. Online Curriculum Centre.
<http://occ.ibo.org/ibis/occ/guest/home.cfm>.
—. "Chemistry Data Booklet." International Baccalaureate Organisation, March 2007.
—. "Chemistry Guide." International Baccalaureate Organisation, March 2007.
—. "IB Chemistry Examination Papers ." Cardiff: International Baccalaureate Organisation, 1999-2008.
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