University:
Missouri State University
Course:
CHM 160 | General Chemistry I
Academic year:

2022
Views:

387

Pages:

32
Author:

Emily Clayton

CHEMICAL REACTIONS The process by which one or more substances are changed into one or more different substances Word Equations  To write a word equation, 1. Write the names of the reactants to the left of the arrow separated by plus signs; 2. Write the names of the products to the right of the arrow, also separated by plus signs. Reactant + Reactant → Product + Product EXAMPLE  Methane + Oxygen → Carbon dioxide + Water EXAMPLE 2 Iron + Oxygen → Iron(III) Oxide EXAMPLE 3 Hydrogen Peroxide →Water and Oxygen Skeleton Equations  Write the formulas of the reactants to the left of the yields sign (arrow) and the formulas of the products to the right.  A skeleton equation is a chemical equation that does not indicate the relative amounts of the reactants and products.  Here is the equation for rusting:  Fe + O2 → Fe2O3  Formula Writing Practice WS Catalyst  A catalyst is a substance that speeds up the reaction but is not used up in the reaction  Without catalyst With Catalyst Important Symbols Balancing Chemical Equations  To write a balanced chemical equation, Write the skeleton equation 2. Use coefficients to balance the equation so that it obeys the la w o f c o n s e rv a tio n o f m a s s .  Remember you want the same number of atoms of each element on each side of the equation. 1. Example Example 2 Example 3 -- Try on your own!!!  Write a balanced chemical equation for the reaction in which sodium hydroxide and calcium bromide react to produce solid calcium hydroxide and sodium bromide. (The reaction occurs in water.) NaOH(aq)+CaBr2(aq) Ca(OH)2(s)+NaBr(aq) 2NaOH(aq)+CaBr2(aq) Ca(OH)2(s)+2NaBr(aq) Summary Write a skeleton equation Count atoms Add/adjust coefficients Reduce coefficients to lowest possible ratio Check your work Warm Up!!  _____Na ClO3 →____ Na Cl + __O2 Chemical Equations from Names  Magnesium and Hydrogen Chloride produce Hydrogen and Magnesium Chloride  Calcium Hydroxide and Lithium Chloride produce Lithium Hydroxide and Calcium Chloride  Decompose Copper (II) oxide into Copper and Oxygen  Aluminum and Iron (III) oxide produce iron and aluminum oxide  combustion of Butane (C4H10) in air to produce carbon dioxide and water Warm Up  ___AgNO3 + __Ni → __Ni(NO3)2 + __Ag The Five Types of Reactions Synthesis Combustion Decomposition Chemical Reactions Double Replacement Single Replacement Chemistry with Synthesis Reactions A + B → AB 1. Synthesis Reactions (Combination)  Two or more reactants produce one product  Examples: NH3 + HCl → NH4Cl H2 + O2 → H2O → Ag2S Al + Cl2 → AlCl3 Ag + S Chemistry with Decomposition Reactions AB → A + B 2. Decomposition  One reactant produces two or more products  Examples Ag2O→ Ag + O2 PCl5 → PCl3 + Cl2 H2O2→ H2O + O2 CuO→ Cu + O2 Chemistry with Single Replacement AB + C → AC + B 3. Single Replacement  One element replaces another element  Must consult the activity series 3. Single Replacement  One element and one compound producing a different element and compound  Examples Fe + H3(PO4) → H2 + Fe3(PO4)2 H2 + CuO → Cu + H2O Zn + HCl → H2 + ZnCl2 Cl2 + KBr → Br2 + KCl Equations Activity Series Worksheet Chemistry with Double Replacement AB + CD → AD + CB 4. Double Replacement A d o u b le -re p la c e m e n t rea c tio n is a chemical change involving an exchange of positive ions between two compounds.  Examples: Al(NO3)3 + NaOH → Al(OH)3 + NaNO3 PbCl2 + Li2SO4 → PbSO4 + LiCl ZnBr2 + AgNO3 → Zn(NO3)2 + AgBr BaCl2 + KIO3 → Ba(IO3)2 + KCl 4. Double replacement  Three main products of a double replacement reaction  Precipitate (solubility table)  Water  Gas 5. Combustion  A c o m b u s tio n re a c tio n  Chemical change  Element or a compound reacts with oxygen  Producing energy in the form of heat and light 5. Combustion A hydrocarbon reacts with oxygen to produce carbon dioxide and water Examples: CH4 + O2 → CO2 + H2O C6H12O6 + O2 → CO2 + H2O