Single Replacement Reactions

4Fe+2H2O+3O2(g)--> 2Fe2O3•H2O

Single Replacement Reactions

A single replacement reaction is a chemical reaction in which one element in a compound is replaced by another element. This means that a new compound is formed and an element is released.

This will only happen if the element being replaced is replaced by a MORE reactive element.

We use an activity series to show how reactive elements are in relation to each other.

The more reactive an element is, the higher it is on the chart, and the less reactive it is the lower it will be. Therefore, elements higher on the chart can replace elements lower than it, but not the other way around.

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A single replacement reaction can be marked by one of the indicators of a chemical reaction (color change, gas emission, a precipitate forming, change in temperature).

If the new element being released in addition to the new compound is a metal, this will be seen as a metal deposit. If it is a gas, it will be seen as bubbles in the solution.

For example, in a thermite reaction, aluminum and iron (III) oxide react so that the aluminum replaces the iron. This reaction is exothermic, and produces so much heat that the iron melts, and this type of reaction is used in iron welding.

Fe2O3 (s) + 2 Al (s) → Al2O3 (s) + 2 Fe (s)

by Kate Kushner, Sylvia Gomez, Aiden Curtis, and Jack

Example 1: Copper sulfate

5th period

In ancient China, copper was first isolated around 475 BCE. Two hundred years later, methods of producing copper were further advanced. One of the methods included using iron to replace copper from copper sulfate solution:

A(CuO)+B(SO3)C(H2O)-->

A(CuO)B(SO3)+C(H2O)

CuO+ H2SO4 -->CuSO4•H2O

A(Cu)B(SO)+C(Fe)--> A(Cu)+B(SO)C(Fe)

CuSO+ Fe -->Cu + FeSO

Example 2

A real-world example of a single replacement reaction is the formation of rust.

Generic Equation

A + BC ----->B + AC

Works Cited

http://www.sartep.com/chem/tutorials/tut.cfm?tutorial=Single%20Replacement%20Reactions&chap=4

http://www.cabrillo.edu/~aromero/CHEM_30A/30A_Handouts/Activity%20Series%20&%20Br%20I%20N%20Cl%20H%20O%20F.pdf

• single replacement reactions consist of a solid being added to a solution
• From top to bottom shows the order from the most reactive metal to the least
• single replacement reactions are NOT reversible.
• cations can only replace cations and anions can only replace anions
• Only anions that occur in single placement reactions are Fluorine, Chlorine, Bromine, and Iodine.

homepage.smc.edu/walker_muriel/single_replacement_battery_lab_procedure.htm

http://www.east-buc.k12.ia.us/03_04/CE1/KE/k_e4.htm

http://www.ric.edu/faculty/ptiskus/reactions/

http://cldfacility.rutgers.edu/content/thermite-reaction

Pictures

http://www.russballard.com/rbv7-workshop/chemistry/Unit-2%20Predicting/module%201%20equations/Activity%20Series%20of%20Metals.jpg

http://www.rsc.org/Education/EiC/issues/2011January/ExhibitionChemistry.asp

For example:

Zn + CuCl2 --->ZnCl2 + Cu

Cl2 + NaBr --->NaCl + Br2

Mg + 2HCl --->MgCl2 + H2

Summary

• If one element in a compound is replaced by an added element and the other is released, a single replacement reaction has occured.
• This looks like A+BC-->B+AC, A being the added element that replaces B in the compound BC. B is released.
• There are certain restrictions on how this can happen, like only cations replacing cations, only anions replacing anions, and only more reactive elements replacing less reactive elements.
• Examples of this reaction include the isolation of copper and the formation of rust.