Presentation on theme: "Reaction Prediction. Basics Research in chemistry involves understanding the properties of reactions. Predicting the products of a reaction is a central."— Presentation transcript:
Basics Research in chemistry involves understanding the properties of reactions. Predicting the products of a reaction is a central topic in chemistry.
Main Areas of Prediction Three main Areas to Reaction prediction: –Activity Series –Combustion –Solubility
Activity Series Single Replacement Reactions For some chemical reactions, we will be able to predict whether or not the reaction will happen at all. For an element to replace another, the lone element must be more active than the element it is replacing in the substance.
The “Activity Series” of Metals Lithium Potassium Calcium Sodium Magnesium Aluminum Zinc Chromium Iron Nickel Lead Hydrogen (for reference) Bismuth Copper Mercury Silver Platinum Gold Higher activity Lower activity
The “Activity Series” of Halogens Fluorine Chlorine Bromine Iodine Halogens can replace other halogens in compounds, provided they are above the halogen they are trying to replace. 2NaCl (s) + F 2(g) 2NaF (s) + Cl 2(g) MgCl 2(s) + Br 2(g) ??? No Reaction! ??? Higher Activity Lower Activity
Example: Zn+ 2 HCl ZnCl 2 + H 2
Example: Thermite Reaction 2 Al + Fe 2 O 3 Al 2 O Fe
Learning Check Use the Activity Series to predict whether the following reaction can occur under normal conditions. Mg + CuSO 4 Fe+ CuSO 4 → Ni + NaCl → Li + ZnCO 3 → Al + CuCl 2 → Will occur Will not occur Will occur
Solution Since Magnesium (Mg) is above Copper (Cu). This reaction will occur. Iron (Fe) is above Copper (Cu). This reaction will occur. Nickel (Ni) is below Sodium (Na). This reaction will not occur. Lithium (Li) is above Zinc (Zn). This reaction will occur. Aluminum (Al) is above Copper (Cu). This reaction will occur.
Parts to the Series Pt. I Highly Reactive Group –Potassium through Sodium Highly reactive—Will react violently with water or anything containing water (i.e. acids) Will react with anything that causes lower groups to react Near High Magnesium and Aluminum –Violent with Acids and anything causing lower groups to react –May spontaneously combust if in fine powder
Part II Moderately reactive –Zinc through Lead –React with acids (Hydrochloric, Sulfuric, etc.) –Produce Hydrogen gas when reacting with acids. –Will react with anything that causes lower groups to react
Part III Not very reactive –Copper through Mercury Typically will not react The only acid they will react with is nitric acid (we’ll talk more about this during the acid/base unit) Unreactive –Gold and Platinum They’re not inert, but darn close. Aqua regia (mixture of nitric acid and hydrochloric acid) will dissolve these metals.
Part IV (That’s a four for those of you that missed that on the exam.) Nitric acid (HNO 3 ) will produce nitrogen dioxide as a product along with the appropriate nitrate. Carbonates (CO 3 2- ) and bicarbonates (HCO 3 - ) will produce carbon dioxide, water and a salt containing the rest of the elements as products. Hydroxides (OH - ) tend to form water if hydrogen is present in the reaction.
Part V Transition metals keep their charge in double replacement reactions. In single replacement, figuring out what charge is a little more difficult. Iron=3, Zinc 2, Copper 2, Silver 1 Metals that react with acids produce the metal salt and hydrogen gas Metals reacting with water produce the metal hydroxide and hydrogen gas
3 Types of Combustion Hydrocarbon-contains carbon and hydrogen. For predictions, you can ignore oxygen in hydrocarbons. Oxygen still matters when balancing. All Combustion reactions involve reacting with oxygen gas.(O 2 )
Hydrocarbon Combustion Complete –Involves an EXCESS of oxygen –Products are always carbon dioxide and water Incomplete –Oxygen is LIMITED –Products are carbon monoxide and water –Soot (unburned hydrocarbon) is a byproduct, but not commonly listed as a product.
Everything else Form the oxide –Burning magnesium produces magnesium oxide –Burning iron produces iron oxides –Burning sulfur produces sulfur dioxide –Burning aluminum produces aluminum oxide
Solubility Rules Solubility Rules are far more complex than single replacement and combustion reactions. We will be spending the next couple of weeks building the necessary information to predict these reactions. The rules are not pretty. You have been warned.