Chapter 8, part IIIWord EquationsWord Equations

Predicting ProductsPredicting Products

Word ProblemsWord Problems

• If given an equation in word format, the If given an equation in word format, the first step is to write the first step is to write the skeletal skeletal equationequation..

• You do this by writing the symbol for the You do this by writing the symbol for the elements, and the formula for each elements, and the formula for each compound.compound.

• Don’t forget your diatomic elements—Don’t forget your diatomic elements—their formula will be Htheir formula will be H22, N, N22, O, O22, F, F22, Cl, Cl22, , Br Br22,or I,or I22..

• Then, balance as normal!Then, balance as normal!

Here are some Here are some examples...examples...

• Lead (II) nitrate and potassium Lead (II) nitrate and potassium chromate react to form lead (II) chromate react to form lead (II) chromate and potassium nitrate.chromate and potassium nitrate.

• Chlorine and potassium iodide react Chlorine and potassium iodide react to form potassium chloride and to form potassium chloride and iodine.iodine.

• Propene (CPropene (C33HH66) and oxygen react to ) and oxygen react to form carbon dioxide and water.form carbon dioxide and water.

• Aluminum hydroxide breaks down to Aluminum hydroxide breaks down to form aluminum oxide and water.form aluminum oxide and water.

Predicting ProductsPredicting Products

• Knowing the basic reaction types Knowing the basic reaction types (combination, decomposition, etc.) (combination, decomposition, etc.) you should be able to predict the you should be able to predict the products in simple reactions.products in simple reactions.

Let’s Predict...Let’s Predict...

•Mg + OMg + O22 •HgO HgO •Zn + HCl Zn + HCl •KK22COCO33 + BaCl + BaCl22 •CHCH44 + O + O22

Balance these equations:

Lithium and oxygen yield lithium Lithium and oxygen yield lithium oxide.oxide.

4 Li + O4 Li + O22 2 Li 2 Li22OO

Hydrochloric acid and iron (III) Hydrochloric acid and iron (III) oxide react to form iron (III) oxide react to form iron (III)

chloride and water.chloride and water.6 HCl + Fe6 HCl + Fe22OO33 2FeCl 2FeCl33 + 3H + 3H22OO

Magnesium carbonate breaks down Magnesium carbonate breaks down to form magnesium oxide and to form magnesium oxide and

carbon dioxide.carbon dioxide.MgCOMgCO33 MgO + CO MgO + CO22

Barium cyanide and sulfuric acid Barium cyanide and sulfuric acid react to form barium sulfate and react to form barium sulfate and

hydrogen cyanide.hydrogen cyanide.Ba(CN)Ba(CN)22 + H + H22SOSO44 BaSO BaSO44 + + 2HCN2HCN

Sodium peroxide and water yield Sodium peroxide and water yield sodium hydroxide and hydrogen. sodium hydroxide and hydrogen.

NaNa22OO22 + H + H22O O NaOH + NaOH + HH22

Iron (III) chloride and ammonium Iron (III) chloride and ammonium hydroxide produce iron (III) hydroxide produce iron (III) hydroxide and ammonium hydroxide and ammonium

chloride.chloride.FeClFeCl33 + NH + NH44OH + Fe(OH)OH + Fe(OH)33 + NH + NH44ClCl

CaICaI22 + Cu(NO + Cu(NO33))22 CaICaI22 + Cu(NO + Cu(NO33))22 CaNO CaNO33 + 2CuI + 2CuI

Al + ClAl + Cl22 2Al + 3Cl2Al + 3Cl22 2AlCl 2AlCl33

Silver plus hydrochloric acid Silver plus hydrochloric acid yields:yields:2Ag + 2HCl 2Ag + 2HCl 2AgCl + H 2AgCl + H22

Ethyne (CEthyne (C22HH22) and oxygen react to ) and oxygen react to form:form:2C2C22HH22 + O + O22 4CO 4CO22 + 2H + 2H22OO

Magnesium chloride breaks down Magnesium chloride breaks down to form:to form:

MgClMgCl22 Mg + Cl Mg + Cl22