Steps to Predicting the Products of Chemical Reactions Honors Chemistry

Once you classify the reaction, then write the products. If it is combustion of a hydrocarbon, then just write H 2 O and CO 2 as products. If it is synthesis, write a compound that contains both elements. (remember to balance the charges for ionic compounds) If it is decomposition, then attempt to break it into two elements or compounds.

If it is single replacement, then replace the single element with the corresponding element in the compound. – A metal will replace the cation in the compound – A non-metal will replace the anion in the compound Remember to take into account the charges on the cation and anion and write the formula correctly! If it is double replacement, then the cation and anions switch places. It is helpful to separate each compound into their cation and anionic parts with their charges. Then switch places, and criss cross the new compounds to make sure they are the correct neutral compound formulas.

Diatomics! Remember the elements that exist in diatomic form. H, N, O, F, Cl, Br and I All exist with two of the element: H 2 N 2 O 2 F 2 Cl 2, Br 2, I 2

A + B  Synthesis/Combination Example: Na(s) + Cl 2 (g)  2 elements indicates synthesis Write Charges for each then write compound Na + Cl - NaCl Balance Reaction NaCl22

AB  Decomposition A single reactant indicates a decomposition reaction. Separate to elements (remember diatomics!) or less complex compounds (we will be memorizing some of these later!) Examples: MgO  NH 4 OH  Mg + O 2 2 NH 3 + H 2 O 2

AB + C  Single Displacement AB is an ionic compound and C is an element. Must use the activity series to determine if the reaction will occur. If element is a metal, it replaces the cation. CuSO 4 + Zn  Cu If element is a non-metal, it replaces the anion. LiI + F 2  Remember correct charges and diatomics! Then balance at the end. + ZnSO 4 I2I2 + LiF 2 2

The Activity Series of the Metals Lithium Potassium Calcium Sodium Magnesium Aluminum Zinc Chromium Iron Nickel Lead Hydrogen Bismuth Copper Mercury Silver Platinum Gold  Metals can replace other metals provided that they are above the metal that they are trying to replace  Metals above hydrogen can replace hydrogen in acids.  Metals from sodium upward can replace hydrogen in water

The Activity Series of the Halogens Fluorine Chlorine Bromine Iodine Halogens can replace other halogens in compounds, provided that they are above the halogen that they are trying to replace. 2NaCl(s) + F 2 (g)  2NaF(s) + Cl 2 (g) MgCl 2 (s) + Br 2 (g)  ??? No Reaction ???

AB + CD  Double Displacement AB and CD are both ionic compounds. Separate each compound & write their charges. Switch places and re-write new compounds. Example: Pb(NO 3 ) 2 + KI  Pb 2+ NO 3 - K + I - Pb 2+ I - K + NO 3 - Balance at the end PbI 2 + KNO 3 22

C x H y + O 2  Combustion Can also be C x H y O z A hydrocarbon and oxygen indicate a combustion reaction. Just write CO 2 and H 2 O as products and then balance (this is the hard part!) C 4 H 10 + O 2  CO 2 + H 2 O