Post on 23-Dec-2015
Decomposition of Nitrogen Triiodide
2 NI3(s) N2(g) + 3 I2(g)
NI3 I2
N2
Exothermic ReactionReactants Products + Energy 10 energy = 8 energy + 2 energy
Reactants
Products
-H
Ene
rgy
Energy of reactants
Energy of products
Reaction Progress
Endothermic ReactionEnergy + Reactants Products
+H Endothermic
Reaction progress
Ene
rgy
Reactants
ProductsActivation Energy
Effect of Catalyst on Reaction Rate
reactants
products
Ene
rgy
activation energy for catalyzed reaction
Reaction Progress
No catalyst
Catalyst lowers the activation energy for the reaction.What is a catalyst? What does it do during a chemical reaction?
An Energy Diagram
activationenergyEa
reactants
products
course of reaction
ener
gy
Animation by Raymond ChangAll rights reserved
Formation of a solid AgCl
AgNO3(aq) + KCl(aq) KNO3 (aq) + AgCl(s)
Single and Double Replacement Reactions
Double-replacement reaction
CaCO3 + 2 HCl CaCl2 + H2CO3
General form: AB + CD AD + CB
Single-replacement reaction
Mg + CuSO4 MgSO4 + Cu
General form: A + BC AC + B
Single displacement is a type of a reaction when a metal reacts with a compound containing a metal, where the single metal in the reaction is more reactive replaces the less reactive metal in the compound.
Single-replacement reaction
Mg + CuSO4 MgSO4 + Cu
General form: A + BC AC + B
DOUBLE DISPLACEMENT REACTIONS: In a double displacement reaction (ionic reaction) the ions of two compounds exchange places in an aqueous solution to form two new compounds.
Double-replacement reaction
CaCO3 + 2 HCl CaCl2 + H2CO3
General form: AB + CD AD + CB
Double Replacement Reaction
Synthesis Reactions - when two compounds or elements combine to make one molecule or compound. A+ B --> AB 2 H2 + O2 -------> 2 H2O
Decomposition Reactions - a compound or molecule breaks down into simpler elements or compounds AB - -> A + B CO2 ------> C + O2
Important Chemical Reactions
Oxidation ReactionsReactant + Oxygen -------> Products
Oxidation reactions are fundamental to our existence
Definition: A chemical change involving oxygen
Oxidation reactions can occur more rapidly in the presence of humidity in the air, or in the presence of light
GALVINIZATION – coating iron materials with zinc to prevent the formation of rust.
Combustion Combustion – Form of oxidation that releases a large
amount of energy (HIGHLY EXOTHERMIC).
Three requirements for a combustion: Fuel – reacts with oxidizing agent to release energy Oxidizing agent – substance that causes a fuel to react
(usually oxygen) Ignition temperature – the required temperature needed to
combust the fuel
Three types of combustions: Rapid – Release a lot of energy in a short period of time Spontaneous – Fuel ignites without the need for outside
energy Slow – Occurs of long period of time
A Combustion reaction usually looks like: Fuel + oxygen ------> CO2 + H2O + Energy
CH4 + O2 -------> CO2 + H2O
Other important Chemical Reactions ...
Cellular Respiration Glucose + Oxygen -----> Carbon Dioxide + Water + Energy
Photosynthesis Light + Carbon Dioxide + Water-----> Oxygen + Glucose