T YPES OF CHEMICAL REACTIONS – P ART B Dr. Chin Chu River Dell Regional High School

U NIT OBJECTIVES  There are millions of reactions.  Can’t remember them all.  Fall into several categories.  Will learn 5 types.  Will be able to predict the products.  For some we will be able to predict whether they will happen at all.  Will recognize them by the reactants

EXERCISE Balancing the following chemical equations: 1.iron(s) + copper(II) sulfate(aq)  copper(s) + iron(II) sulfate(aq) 2.fluorine(g) + magnesium chloride(aq)  chlorine(g) + magnesium fluoride(aq) 3.sodium(s) + water(l)  sodium hydroxide(aq) + hydrogen(g) Do you see the patterns?

S INGLE - REPLACEMENT REACTIONS  Atoms of one element replace the atoms of another element in a compound.  General Equation: AB + C  BC + A  Animation:  Reactants must be an element and an ionic compound  Products will be a different element and compound.

S INGLE - REPLACEMENT REACTIONS  Metal replaces metal ions (and hydrogen).  Zn + HCl   Think water (H 2 O) as HOH.  Elemental metal replaces H and combine with hydroxide.  Na + H 2 O 

S INGLE - REPLACEMENT REACTIONS  Demonstrations:  +   When two compounds are mixed together, NO guarantee a chemical reaction will occur!  Some elements are more reactive than the others.  More reactive ones replace the less reactive ones.  REACTIVITY SERIES.  There are two reactivity series, one for metals and the other for halogens.

S INGLE - REPLACEMENT REACTIONS METALS: Lithium(cont.) RubidumCopper PotassiumSilver CalciumPlatinum SodiumGold Magnesium Aluminum Manganese Zinc Iron Tin Lead HALOGENS: Fluorine Chlorine Bromine Iodine Decreasing Reactivity  Single-replacement reaction only proceeds when the element is higher on the reactivity list than the ion.

S INGLE - REPLACEMENT REACTIONS Examples:  Reactions involving metallic elements as reactants. Zinc is lower on the reactivity list than Ca ion. No reaction.  CaCl 2 (aq) + Zn(s)  x  3ZnCl 2 (aq) + 2Al(s)  3Zn(s) + 2AlCl 3 (aq) Aluminum is higher on the reactivity list than zinc. Single-replacement reaction proceeds.

S INGLE - REPLACEMENT REACTIONS Examples:  Reactions involving halogen elements as reactants. Bromine is lower on the reactivity list than chlorine. No reaction.  NaCl(aq) + Br 2 (l)  x  2NaI(aq) + Br 2 (l)  I 2 (s) + 2NaBr(aq) Bromine is higher on the reactivity list than iodide ion. Single-replacement reaction proceeds.

S INGLE - REPLACEMENT REACTIONS Exercises:  Predict whether the following single-replacement reactions will take place. If yes, write down the balanced chemical equations.  Cu(s) + AgNO 3 (aq)   Fe(s) + ZnBr 2 (aq)   F 2 (g) + NaCl(aq)   Zn(s) + FeBr 2 (aq)   Mg(s) + CaCl 2 (aq)   Br 2 (l) + LiI(aq)   Cl 2 (g) + KBr(aq) 