Quiz Review for Wednesday, February 15th, 2012

Tomorrow (Wednesday, February 15th, 2012) will be a quiz over balancing equations, classifying types of reactions, the use of the activity series chart, and the use of the solubility table. The types of reactions were given in your notes, but I will summarize them again in this blog post. The types of reactions and how they are abreviated are shown below. The key to the types of reactions on the balancing reactions worksheet are given below.

• synthesis reactions (shown as "syn" below) - less complex atoms or molecules become more complex molecules. Remember, a three element compound is more complex than a two element compound.


• decomposition reactions (shown as "decomp" below) - more complex molecules become less complex molecules or atoms. A two element compound is less complex than a three element compound.


• dissociation reactions (shown as "diss" below) - ionic compounds, when placed in water, dissolve in water to go from solid to aqueous. The aqueous products will always be shown as ions with charges.


• combustion reactions (shown as "comb" below) - elements oxygen (O2) must always be a reactant. Each product must contain the element oxygen. **All hydrocarbons (compounds that contain the elements carbon, hydrogen, and sometimes oxygen), when combusted, produce the products carbon dioxide and water. Both CO2 and H2O have oxygen in them.


• double replacement reactions (shown as "D.R." below) - two aqueous ionic compounds switch ions. The metal (positive ion) of one compound possibly combines with the non-metal (negative ion) of another and vice-versa. A new state of matter matter must be produced. This is usually a precipitate (solid), but not always.


• single replacement reactions (shown as "S.R." below) - a single element and an ionic compound are reactants. A general rule is "a metal replaces a metal and a non-metal replaces a non-metal" for single replacement reactions. If the single element is a metal and is more active than the metal in the ionic compound, the more active metal will replace the less active metal in the compound. Example #1: Cu +2AgNO3 --> Cu(NO3)2 + 2Ag OR a more active non-metal will replace a less active non-metal in the ionic compound. Example #2: Cl2 + CaBr2 --> CaCl2 +Br2. A metal or non-metal's reactivity can be determined by where it is on the activity series chart given in class. If a less active element is the element by itself, it will not replace the more active element. This will be classified as a NO REACTION (N.R.)

**Some reactions can have more than one type of classification. This often occurs with synthesis reactions that involve elemental oxygen as a reactant. They can be often be classified as combustion reactions also. Also, some of the reactions in the worksheet do not always fit nicely into a category, so that is indicated by a question mark. You will not be given any questionable reactions on the quiz.

The quiz will require you to do the following:

• Balance equations and classify them just like the work sheet given in class.


• You will also be shown single replacement reactions and asked to predict if a reaction will occur because the single element reactant is more active than its like element in the compound or the reaction will not occur because the single element reactant is less active than its like element in the compound.


• You will be given ionic compounds, and using a solubility table, determine if the compound is soluble in water (aqueous) or not soluble in water (solid).

**You will be able to use your own periodic table and solubility / activity series table on the quiz. The quiz will be going into the "Assessment Category" of your grade.