Advanced Placement Chemistry 1985 Free Response Questions

9)

 

Substance

Melting Point (oC)

H2

-129

C3H8

-190

HF

-92

CsI

621

LiF

870

SiC

>2,000

(a) Discuss how the trend in the melting points of the substances tabulated above can be explained in terms of the types of attractive forces and/or bonds in these substances.

(b) For any pairs of substances that have the same kind(s) of attractive forces and/or bonds, discuss the factors that cause variation in the strengths of the forces and/or bonds.

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