Single Replacement Reactions Silver replacing Copper in reaction of silver nitrate and copper Link to silver nitrate and copper

“Like replaces Like” Element + Compound → Compound + Element Metals replace metals and halogens replace halogens. A + BC → AC + B Where A, B are metals, C is a nonmetal or negative polyatomic ion. A2 + BC → BA + C2 Where B is a metal, A and C are halogens (F, Cl, Br or I) Link to McGraw-Hill tutorial

Example #1: Demo of Aluminum + Copper(II) chloride Al (s) + CuCl2 (aq) → Aluminum Cu+2 Cl -1 Copper(II) Chloride solution Blue color is due to presence of Cu+2 ion dissolved in water

What is the reddish solid that formed What is the reddish solid that formed? Why has the solution turned from blue to colorless? Immediately after mixing Final appearance after 30 minutes

Predicting Products of Al + CuCl2 rxn Neutral metals don’t dissolve; + charged metals ions do dissolve Lines of evidence: Reddish solid = copper Blue color disappears = Cu+2 is disappearing Al dissolves (clear, colorless ion in water) Conclusion: Al has replaced Cu Al (s) + CuCl2 (aq) →

Predicting Products of Al + CuCl2 rxn Neutral metals don’t dissolve; + charged metals ions do dissolve Lines of evidence: Reddish solid = copper Blue color disappears = Cu+2 is disappearing Al dissolves (clear, colorless ion in water) Conclusion: Al has replaced Cu Al (s) + CuCl2 (aq) → Al+3Cl-1 + Cu Al (s) + CuCl2 (aq) → AlCl3 (aq) + Cu (s)

Predicting Products of Al + CuCl2 rxn Neutral metals don’t dissolve; + charged metals ions do dissolve Lines of evidence: Reddish solid = copper Blue color disappears = Cu+2 is disappearing Al dissolves (clear, colorless ion in water) Conclusion: Al has replaced Cu Al (s) + CuCl2 (aq) → Al+3Cl-1 + Cu Al (s) + CuCl2 (aq) → AlCl3 (aq) + Cu (s) 2Al(s) + 3CuCl2 (aq) → 2AlCl3 (aq) + 3Cu (s)

Halogen replaces Halogen A2 + BC → BA + C2 Where B is a metal, A and C are halogens (F, Cl, Br or I) KI(aq) + Cl2 (aq) →

Halogen replaces Halogen A2 + BC → BA + C2 Where B is a metal, A and C are halogens (F, Cl, Br or I) KI(aq) + Cl2 (aq) → K+1Cl-1 + I2 (diatomic!)

Halogen replaces Halogen A2 + BC → BA + C2 Where B is a metal, A and C are halogens (F, Cl, Br or I) KI(aq) + Cl2 (aq) → K+1Cl-1 + I2 (diatomic!) KI(aq) + Cl2 (aq) → KCl + I2

Halogen replaces Halogen A2 + BC → BA + C2 Where B is a metal, A and C are halogens (F, Cl, Br or I) KI(aq) + Cl2 (aq) → K+1Cl-1 + I2 (diatomic!) KI(aq) + Cl2 (aq) → KCl + I2 2KI(aq) + Cl2 (aq) → 2 KCl + I2 Link to Potassium Iodide and Chlorine

Activity Series Some processes are spontaneous in one direction but not the other Example: Rock can fall from a cliff to the ground, but a rock on the ground can’t climb the cliff by itself.

Single replacement rxns will run in one direction but not the other Example: Mg + 2 HCl → MgCl2 + H2 But MgCl2 + H2 → No reaction Link to MgCl2 + H2 video Mg + HCl Energy MgCl2 + H2 Rxn Progress

Data from your lab Metal Mg+2 (MgCl2) Cu+2 (CuCl2) Zn+2 (ZnSO4) Mg X + NR Zn X = not tested NR = No reaction + = reaction Link to activity series animations

Using an activity series chart (table 3-3 on page 7 of lab manual) to predict whether a rxn will occur Is the element in reaction a metal or a halogen? (To decide which column chart to use) What is the metal or halogen in the compound? If the element is higher on the activity chart than the metal or halogen in the compound the reaction will occur.

Example #1: Will the following rxn occur? Ag + HCl → Step #1: Element is Ag = metal Step #2: Metal in compound is always first element in formula = H. On metal activity chart, is element, Ag, higher than H? No, Ag is lower No reaction will occur.

Example #2: Will a rxn occur? F2 + KCl → Step #1: Element = F2, a halogen Step #2: Halogen is formula is always second = Cl Step #3: Is element (F) higher than halogen (Cl) in compound? Yes; rxn will occur. Products: Cl2 and KF

Applications of Activity Series: A more active metal being used to protect a metal supporting a structure Using Zinc (more active) to protect iron (less chemically active but physically stronger); the iron inside the concrete is helping to support the weight of the bridge