What is a Chemical Reaction A Chemical reaction occurs when ever a chemical bond is formed broken or rearranged A chemical reaction will always create a new substance Energy and Chemical Reactions ID: 1042859
Download Presentation The PPT/PDF document "Basic Chemical Reactions" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
1. Basic Chemical Reactions
2. What is a Chemical Reaction?A Chemical reaction occurs when ever a chemical bond is formed, broken or rearranged.A chemical reaction will always create a new substance.
3. Energy and Chemical ReactionsWhen a reaction occurs it’s either going to give off energy or take in energy.Exergonic reactions – release energy (usually breaking bonds)Endergonic reactions – take in energy (usually making bonds)
4. Chemical EquationsA chemical equation contains the following:Reactants: The starting chemicalsProducts: The ending (resulting) chemicalsYield sign: The arrow that shows the change.Coefficients: Numbers in front of the molecule.Subscript: Number behind and at the bottom of the atom or molecule.
5. BalancingChemical Equations should balance.The number of atoms in the reactants should match the number of atoms in the product.You can not create or destroy energy or matter. Is this equation balanced?
6. MolesWhen trying to count very small particles like atoms a counting unit was created called the mole.1 mole = 6.022 x 1023 particlesIt is the number of particles in exactly 12 grams of carbon.Amedeo Avegadro was the Italian scientist who came up with this unit, so it is also called Avegadro’s Number.
7. Balancing Equations and Moles When we balance a chemical equation we are looking at the ratio of reactants and products. This is called a Molar Ratio. Example: 2Mg + O2 2MgOThe molar ratio of magnesium to oxygen is 2:1So for every 2 moles of magenesium that react 1 mole of Oxygen will also react.
8. Law of Definite ProportionsA compound will always contain the same elements in the same proportions regardless of how the compound is made or how it is formed.
9. Types of chemical ReactionsThere are three main types of chemical reactions:Synthesis ReactionsDecomposition reactionExchange reactions
10. Synthesis ReactionsSynthesis means to combine.So a synthesis reaction is one where we are forming bonds to make a new molecule.This is the reaction that takes amino acids and combines them to make a protein.Anabolic activities.
11. Decomposition ReactionsA decomposition reaction is when a lager molecule are broken down into its parts.These are called Catabolic activitiesExample: Glycogen produced by the liver is broken down into the sugar Glucose.
12. Exchange ReactionsIn an exchange reaction parts of the reactant molecules change partners.Example: When Glucose takes a phosphate group from ADT making ATD and GlucoseP.
13. Oxidation-reduction reactionThere is a very important reaction called an Oxidation- reduction reaction (redox reaction)Redox reactions are both a decomposition and exchange reaction.
14. Oxidation-reduction reactionIn a redox reaction an electron is given off by one reactant and accepted by another.The reactant loosing the electron is said to have been oxidized.The reactant taking the electron is said to have been reduced.
15. Oxidation-reduction reactionWhen an ionic bond is formed it is a type of redox reaction. However, when Hydrogen molecules are separated from their original molecules they take their electrons with them. This is also considered a redox reaction.
16. Rate of ReactionsFor a reaction to occur Valence electrons must slam into each other with enough force to either break bonds or make bonds.There are factors that will influence how well these valence electrons collide.-TemperatureConcentrationParticle Size Catlysts
17. Reaction Rate and TemperatureAn increase in temperature increase the kinetic energy of the particles and there fore they hit each other with more force.
18. Reaction Rate and ConcentrationThe higher the Concentration the more likely the two reactants are to successfully hit each other and therefore react faster.
19. Reaction Rate and Particle SizeGenerally smaller particles move faster than large ones and therefore tend to collide more frequently.
20. Reaction Rates and CatalystsCatalysts are chemicals called enzymes that sped up the rate of reactions with out having to increase our body temperature.