3.17. Balancing Chemical Equations http://www.ck12.org
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/5087Summary
- A chemical equation represents the changes that occur during a chemical reaction. It has the general form:
Reactants→Products. All chemical equations must be balanced. This means that there must be the same
number of each type of atom on both sides of the arrow. - Coefficients are used to balance chemical equations. A coefficient is a number placed in front of a chemical
symbol or formula. It shows how many atoms or molecules of the substance are involved in the reaction. - To balance a chemical equation, place coefficients as needed in front of the symbols or formulas so the same
number of each type of atom occurs in both reactants and products.
Explore More
Practice balancing chemical equations by completing the worksheet at this URL: http://chemistry.about.com/libra
ry/formulabalance.pdf.
Review
- Which of the following chemical equations is balanced?
a. Zn + HCl→ZnCl 2 + H 2
b. 2 Zn + 2 HCl→ZnCl 2 + H 2
c. 2 Zn + HCl→ZnCl 2 + H 2
d. Zn + 2 HCl→ZnCl 2 + H 2 - Balance this chemical equation: CH 4 + O 2 →CO 2 + H 2 O
- Sam was given the following equation to balance: H 2 O→H 2 + O 2. She balanced it as follows: 2 HO→H 2
- O 2. What did she do wrong? What is the correct way to balance the equation?