Chapter 10: Chemical Reactions How can you tell there is a chemical Change? Temperature Light Color Gas Bubbles

The Chemical Equation: Section 1 What do we start with? Reactants = Starting substances Products = Substances formed

The Word Equation Describing the reaction Reactant 1 + Reactant 2 --> Products Iron(s) + chlorine(g) --> Iron (III) chloride(s) How is this Read: Iron and chlorine react to produce iron (III) chloride

The Skeleton Equation Replace the words with the symbols Iron(s) + chlorine(g) --> Iron (III) chloride(s) Fe(s) + Cl2(g) --> FeCl3(s) Whats Wrong with this Equation? Count the number of atoms on each side of the arrow. Needs to be balanced! let’s practice skeleton equations first

Practice Makes Perfect Write the skeleton equations for the following word equations hydrogen(g) + bromine(g) --> hydrogen bromide (g) H2(g) + Br2(g) --> HBr(g) carbon monoxide(g) + oxygen(g) --> carbon dioxide(g) CO(g) + O2(g) --> CO2(g) potassium chlorate(s) --> potassium chloride(s) + oxygen(g) KClO3(S) --> KCl(S) + O2(g)

The Balanced Chemical Equation Remember: Matter is neither created nor destroyed Fe(s) + Cl2(g) --> FeCl3(s) Count the number of atoms of each element Cl Fe Cl + Fe --> Cl What’s the Problem?

+ --> Now Count the atoms. 2 2 3 How do We Fix It? Balance the equation 2 2 3 Fe(s) + Cl2(g) --> FeCl3(s) Cl Fe Cl Fe Cl + --> Cl Fe Fe Cl Now Count the atoms. Remember: Matter is neither created nor destroyed

5 Easy Steps for Balancing Equations Write the skeleton equation Count the atoms of the reactants Count the atoms of the the products Place coefficients to make the # of atoms equal on both sides of the equation Write the coefficients in their lowest possible ratio

Practice Write chemical equations for each of the following reactions In water, Iron (III) chloride reacts with sodium hydroxide, producing solid iron (III) hydroxide and sodium chloride.

Liquid carbon disulfide reacts with oxygen gas, producing carbon dioxide gas and sulfur dioxide gas.

Solid zinc and aqueous hydrogen sulfate reat to produce hydrogen gas and aqueous zinc sulfate.

--> A + B AB CO(g) + O2(g) --> CO2(g) Synthesis Reactions: Two Elements combine to produce one new compounds --> A + B AB CO(g) + O2(g) --> CO2(g)

B --> A + AB 2H2(g) + O2(g) --> 2H2O(g) Combustion Reaction Oxygen comines with a substance and releases energy in the form of heat and light. B --> A + AB 2H2(g) + O2(g) --> 2H2O(g)

The solids aluminum and sulfur react to produce aluminum sulfide

Water and dinitrogen pentoxide gas react to produce aqueous hydrogen nitrate.

The gases nitrogen dioxide and oxygen react to produce dinitrogen pentoxide gas.

Ethane gas (C2H6) burns in air, producing carbon dioxide gas and water vapor

Single compound breaks down into 2 or more elements Decomposition Reactions Single compound breaks down into 2 or more elements AB --> A + B Example: NH4NO3(s) --> N2O(g) + 2H2O(l) 2NaN3(s) --> 2Na(s) + 3N2(g)

1 element replaces the atoms of another element in a compound Replacement Reactions Single Replacement: 1 element replaces the atoms of another element in a compound A + BX --> AX + B Double Replacement: The exchange of ions between two compounds AX + BY --> AY + BX

Practice K K(S) + ZnCl2(aq) --> Zn(s) Cl(aq) + + + Cl2(g) + HF(aq) --> Cl(aq) H F(g) + Fe Fe(s) + Na3PO4(aq) --> Na(s) PO4(aq) +

Practice AX + BY --> AY + BX Aqueous lithium iodide and aqueous silver nitrate react to produce solid silver iodide and aqueous lithium nitrate.

Practice AX + BY --> AY + BX Aqueous barium chloride and aqueous potassium carbonate react to produce solid barium carbonate and aqueous potassium chloride.

Practice Aqueous sodium oxalate and aqueous lead(II) nitrate react to produce solid lead(II) oxalate and aqueous sodium nitrate.

Section 3: Reactions in Aqueous Solutions Terms to know: solutes: substance dissolved in water solvent: what the substance is dissolved in (ie. water)

Complete Ionic Equation Shows all particle in a solution Here’s the equation + --> + 2Na+(aq) 2NaOH(aq) 2OH-(aq) Cu2+ CuCl2(aq) 2Cl-(aq) 2NaCl(aq) Cu(OH)2(s) Cu(OH)2(s) 2Na(aq) 2Cl(aq) Now Separate ALL the ions in aqueous solution + + + --> + +

+ --> Spectator Ions Here’s the complete Ionic Equation Ions that do not participate in a reaction Here’s the complete Ionic Equation 2Na+(aq) 2OH-(aq) Cu2+ 2Cl-(aq) 2Na(aq) 2Cl(aq) Cu(OH)2(s) + --> Now Cancel out all the ions that are NOT part of the reactions (ions that do not produce the solid)

+ + + --> + Net Ionic Equation Remove the Spectator ions 2Na+(aq) Includes only the particles that participate in a reaction Here’s the net ionic equation with spectator ions cancelled 2Na+(aq) + + 2Cl-(aq) + --> 2OH-(aq) Cu2+ 2Na(aq) 2Cl(aq) + Cu(OH)2(s) Remove the Spectator ions

3 Types of Aqueous Reactions 1. Reactions that form Precipitates (solids) 2NaOH(aq) + CuCl2(aq) --> 2NaCl(aq) + Cu(OH)2(s). 2. Reactions that form Water HBr(aq) + NaOH(aq) --> H2O(l) + NaBr(aq) 3. Reactions that form Gases 2HI(aq) + Li2S(aq) --> H2S(g) + 2LiI(aq)

Practice 1. Reactions that form Precipitates (solids) 2NaOH(aq) + CuCl2(aq) --> 2NaCl(aq) + Cu(OH)2(s).

Practice 2. Reactions that form Water HBr(aq) + NaOH(aq) --> H2O(l) + NaBr(aq) H+(aq) Br-(aq) Na+(aq) OH(aq) H2O(l) Na+(aq) Br-(aq) H+(aq) + + + OH(aq) --> + + H2O(l) Write the complete Ionic equation Cancel the spectator ions Write the net ionic equation + -->

Practice 3. Reactions that form Gases 2H(aq) 2HI(aq) + Li2S(aq) --> H2S(g) + 2LiI(aq) 2I(aq) 2Li(aq) S(aq) H2S(g) 2Li(aq) 2I(aq) 2H(aq) + + + S(aq) --> H2S(g) + + Write the complete Ionic equation Cancel the spectator ions Write the net ionic equation + -->