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Chemical Reactions. Today. Begin learning about different types of chemical reactions (synthesis, decomposition and combustion) Practice these reactions! Worksheet (homework if you don’t complete in class). Types of chemical reactions. Synthesis Single displacement Combustion
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Today • Begin learning about different types of chemical reactions (synthesis, decomposition and combustion) • Practice these reactions! • Worksheet (homework if you don’t complete in class)
Types of chemical reactions • Synthesis • Single displacement • Combustion • Decomposition • Double displacement Today
General Chemical equations • General Chemical Equation (GCE): equation the uses letters of the alphabet in place of chemical symbols to show the movement of its components in a reactions (ex. A + B = AB) • Mg + O2 = • Balanced?
Synthesis reactions • Two elements combine to form a compound • Either a metallic element + a non-metallic element OR two non-metallic elements • Element + Element = Compound • GCE is A + B = AB • Ex. Mg + O2 = MgO • Balanced?
Examples • Write a skeleton equation for when sulfur(S8) an oxygen(O2) combine. • Write a skeleton equation for when hydrogen(H2) and Nitrogen(N2) combine.
Single displacement • An element reacts with an ionic compound • The element becomes part of the ionic compound while one of the elements in the compound become an element by itself • Either two metals or two non metals with switch places • The GCE is AB + C = CB + A • Copper (II) Chloride + Aluminum Aluminum(III) Chloride + Copper • CuCl2 + Al AlCl2 + Cu
Example • Write the skeleton equation for a Potassium Iodide(KI) and Bromine (Br2) reaction
Combustion of Hydrocarbons • a compound or element rapidly combines with oxygen gas (usually giving off a large amount of heat and light) • When hydrocarbons react in a a combustion reaction the result is always CO2 and H2O • Hydrocarbons have the formula CxHY • Example: methane gas CH4 • The GCE for a hydrocarbon combustion reactions is: • CxHY+ O2 CO2 + H2O CH4 + O2 CO2 + H2O
Today • Review first 3 types of reactions • Combustion demonstration • Continue with types of reactions note (single and double displacement) • Single displacement demonstration • Double displacement reaction lab activity • Worksheet
Decomposition reactions • A compound is broken apart into two or more elements and/or simpler compounds • The compound is broken down to either one metallic and one non-metallic element or two non-metallic elements • Compound Element + Element • The GCE is AB = A + B • When Mercury (II) Oxide is heated • HgO Hg + O2
Example • Write the skeleton equation for the break down of water into Hydrogen(H2) and oxygen(O2) • Write the skeleton equation for when Calcium Chloride is broken down (by heat)
Double Displacement • The positive of negative ions in two dissolved ionic compounds switch places • The GCE is AB + CD = AD + CB • Positive switches with positive, negative switches with negative • When Magnesium hydroxide reacts with Silver nitrate it produces magnesium nitrate and silver hydroxide • Mg(OH)2 + AgNO3 Mg(NO3) + AgOH
Example • Write the skeleton equation of a double displacement reaction between Lead (II) nitrate(Pb(NO3)2) and sodium iodide (NaI)
Neutralization Reactions • When we looked at Acids and Bases in class last week we saw that when we combine an acid and a base they create a salt and H2O. • This is a double displacement reaction! • A GCE for that neutralization reaction would be • HB + XOH XB + H20 • When you apply that to a specific reaction (Hydrochloric acid and Sodium Hydroxide) you can see that: • HCl + NaOH NaCl+ H2O