http://www.ck12.org Chapter 11. Chemical Reactions
11.1 Chemical Equations
Lesson Objectives
- Give examples of historically significant chemical recipes and equations.
- Briefly describe the major milestones that took place in developing the chemical recipe of gunpowder.
- Understand mass relations between reactants and products for a given chemical process.
- Be able to use stoichiometric coefficients in chemical equations.
- Be able to balance chemical equations.
Lesson Vocabulary
- stoichiometric coefficient: The letters a, b, c, and d where A and B are reactants, and C and D are products.
The stoichiometric coefficients indicate the relative amounts of reactants and products. - balanced chemical equation: An equation where the number of atoms of each element on the reactant side
is equal to the number of atoms on the product side.
Check Your Understanding
- Which of the following are physical changes and which are chemical changes?
a. melting of ice
b. a burning candle
c. melting of candle wax
d. sublimation of dry ice to CO 2 gas.Introduction
Ever since the 9thcentury, humans have been fascinated with the nature of explosions. Whether to scare away evil
spirits, to light up the night sky in celebration, or to be used in warfare, our understanding of gunpowder is based on
our understanding of chemical recipes. Our ability to modify, share, and replicate them has allowed us to develop
new recipes and to refine existing ones. Chemical reactions can be described in terms of chemical equations. They
are the foundation of our modern day chemical recipes.