Chemical Reactions

Information Contained in a Chemical Equation

Reactants and Products Reactants are always to the left of the arrow Products are always listed to the right of the arrow

Required conditions are listed over the arrow Temperature, enzymes, pressure, other required

substances such as chlorophyll or sunlight, etc.

States of matter of reactants and products Solid, liquid, gas (s, l, g) Special conditions such as precipitate, aqueous (ppt,

aq)

Evidence for a Chemical Changehttp://chemistry.about.com/od/demonstrationsexperiments/tp/myfavorites.htm

1) Gas formation (bubble) 2) Formation of a solid (precipitate, aka ppt) 3) unexpected color change4) Light, heat, or sound emission5) Change in temperature indicating a change in heat (endo- vs. exothermic rxns)

NOTE: the only way to truly determine if a chemical reaction has taken place is to analyze the chemical make up of the products in relation to the reactants you started with

Balancing Equations

Coefficients are used to create a balanced chemical equation that will reflect what happens in nature based upon the law of conservation of mass.

For each element involved in a chemical reaction, there must equal amounts indicated in the reactants and products

Types of Equations

Word equation: products and reactions are described no quantities or formulas given

Formula equation: chemical formulas are listed (subscripts)

Balanced chemical equation: coefficients are used to indicate quantities These coefficients allow the balanced equation to

mirror real life chemical reactions and how they relate to the law of conservation of mass

Types of Chemical Reactions Combustion

O2 is always a reactant Synthesis

two single components form a compound Decomposition

A single compound is broken apart Single Replacement

One element replaced a member of a compound according to the rules of the activity series

Double Replacement The members of two different compounds switch

partners according to our compound rules (one member of each pair must be an anion, one must be a cation)

Using the Activity Series

The activity series lists common elements in a hierarchical list

When one element is above another element on the activity series, it means that this first element can replace the second element in a single replacement chemical reaction

If it is below the second element on the series, it will not be able to replace that element and the reaction will not occur

Additional Resources

This brief PowerPoint is simply a summary of the concepts we discussed in detail in our classroom unit.

Please utilize the documents on School Loop that were given out in class for more detailed, step-by-step information and examples

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