Predicting Products and The Activity Series

Initial Questions Do all reactions occur? How do you know when a reaction occurs and when it does not? Today we learn about the learn activity series. What do you think the activity series is and what does it mean to reactions?

Objectives Define and explain activity series. Use the activity series to predict is a reaction will occur.

Does it happen or not??? In order to correctly predict the products of a single replacement reaction, the chemical activity of the elements that will potentially switch places needs to be considered. In order for an element to replace another, it must be more active. A more active element will replace a less active element. If this is not the case, then no reaction occurs.

The Activity Series Found on page 437

Which is more active??? For example, for a set of reactants: magnesium and copper sulfate, you need to determine if the magnesium will replace the copper ion. You check the activity series. You find that the magnesium is more active than the copper and therefore the magnesium will replace the copper and the reaction will proceed.

Examples: Will the following reactions occur? If yes, what are the products? If no, write NR. 1. chromium + lead (II) chloride 2. zinc + potassium hydroxide 3. magnesium + sulfuric acid 4. iodine + sodium chloride 5. fluorine + sodium chloride

Examples: Will the following reactions occur? If yes, what are the products? If no, write NR. 1. chromium + lead (II) chloride Yes CrCl2 + Pb 2. zinc + potassium hydroxide No 3. magnesium + sulfuric acid Yes MgSO4 + H2 4. iodine + sodium chloride No 5. fluorine + sodium chloride Yes NaF + Cl2

Double Replacement Predict the product Recognize if the reaction will occur or not.

Double Replacement Na2SO4(aq)+ CaCl2(aq)®Ca+2 SO42- + Na+1Cl-1 Two things replace each other. Reactants must be two ionic compounds or acids. Usually in aqueous solution Na2SO4(aq) + CaCl2(aq) ® The positive ions change place. Na2SO4(aq)+ CaCl2(aq)®Ca+2 SO42- + Na+1Cl-1 Na2SO4(aq) + CaCl2(aq) ® CaSO4(s) + 2NaCl(aq)

To Double Replace or Not to Double Replace? That is the Question? Will only happen if one of the products doesn’t dissolve in water and forms an insoluble solid (s), precipitate (ppt). or is a gas that bubbles out. or water forms, H2O (neutralization reaction).

Initial Questions What does aqueous mean? What are things that are able to form aqueous solution? Generally aqueous reactions are double replacement reactions. What three things drive double replacement reactions?

Does it happen? Deciding whether a double replacement reaction will occur naturally is actually a matter of predicting whether an insoluble product can form. Solubility rules are used to determine this. The solubility rules are a listing of the solubility of various substances in water. Some compounds are listed as soluble and other compounds are listed as insoluble. If one of the products formed is insoluble, it is this insoluble product that is the precipitate that forms in the reaction. If no insoluble precipitate, gas or molecular compound forms then there is no aqueous reaction.

Solubility Rules Can you read the solubility rules? Do you have to memorize them? Which do you need to know by heart? They are on page 434

Solubility Rules Practice Predict whether each of the following will be soluble (aq) or an insoluble ppt (s): KCl Na2SO4 CaSO4 AgSO4 Na2CO3 MgS

Solubility Rules Practice KCl(aq) Na2SO4(aq) CaSO4(s) AgSO4(s) Na2CO3(aq) MgS(s)

Examples 1. Mix silver nitrate and sodium bromide. Does a reaction occur?

Examples 1. Mix silver nitrate and sodium bromide. Does a reaction occur? Yes - AgBr ppt 2. Mix sulfuric acid and barium chloride. Does a reaction occur?

Examples 1. Mix silver nitrate and sodium bromide. Does a reaction occur? Yes - AgBr ppt 2. Mix sulfuric acid and barium chloride. Does a reaction occur? Yes - BaSO4 ppt 3. Mix lithium chloride and copper (II) acetate. Does a reaction occur?

Examples 1. Mix silver nitrate and sodium bromide. Does a reaction occur? Yes - AgBr ppt 2. Mix sulfuric acid and barium chloride. Does a reaction occur? Yes - BaSO4 ppt 3. Mix lithium chloride and copper (II) acetate. Does a reaction occur? No – everything is soluble

Learning Check Which of the following reactions is double replacement? A. 2Al(s) + 3H2SO4(aq)  Al2(SO4)3(aq) + 3H2(g) B. Na2SO4(aq) + 2AgNO3(aq)Ag2SO4(s)+ 2NaNO3(aq) C. 3C(s) + Fe2O3(s)  2Fe(g) + 3CO(g)

Writing the products

Double Replacement Two elements in reactants take the place of each other AB + CD  AD + CB AgNO3(aq)+ NaCl(aq) AgCl(s) + NaNO3(aq)

Double Replacement Two elements in reactants take the place of each other AB + CD  AD + CB Zn(OH)2(aq) + 2HCl(aq)  ZnCl2(aq) + 2H2O(l)

Double Replacement Two elements in reactants take the place of each other AB + CD  AD + CB FeS(aq) + 2HCl(aq)  FeCl2(s) + 2H2S(aq)