Chemical Reactions and Thermochemistry

8

These skills are usually tested on the SAT Subject Test in Chemistry. You
should be able to...

Identify the driving force for these four major types of chemical

reactions, and write balanced equations for each: combination (or

synthesis), decomposition (or analysis), single replacement, and

double replacement.

Explain hydrolysis using a balanced equation.

Identify and explain graphically enthalpy changes in exothermic

and endothermic reactions.

Use Hess’s Law to show the additivity of heats of reactions.

This chapter will review and strengthen these skills. Be sure to do the
Practice Exercises at the end of the chapter.

TIP

Know the four types of chemical reactions:

1. Combination or synthesis


2. Decomposition or analysis


3. Single replacement


4. Double replacement

The many kinds of reactions you may encounter can be placed into four basic

categories: combination, decomposition, single replacement, and double
replacement.
The first type, combination, can also be called synthesis. This means the
formation of a compound from the union of its elements. Some examples of this
type are: