Chemical Reactions(MS-PS1-2) Analyze and interpret data on properties of a substance before and after an interaction to determine if a chemical reaction has occurred.
• Chemistry is the study of • the composition/properties of matter• the changes that matter undergoes
Chemistry Defined
Matter Defined
• Anything that has mass and takes up space (has volume)
• Made of atoms
• Chemistry is the study of • the composition/properties of matter• the changes that matter undergoes
Chemistry Defined
Properties of Matter
REMINDER: All matter has 2 types of properties 1.) Physical Properties 2.) Chemical Properties
Examples of Physical Properties• Mass• Volume• Density• Color• Size• Melting and
Boiling Point• Hardness• Odor• Taste • State of matter• Texture• Luster (shine)• Flexibility• Heat (thermal)
conductivity
• Electrical conductivity
• Solubility • Shape• Viscosity• Ductility• Malleability
Reactivity Flammability Corrosivenessability of the substance to combine chemically with other substances
ability of the substance to burn
ability of a substance to destroy and damage other substances upon contact
Instability Tarnishing Rusting
the ability of a substance to easily change even under normal environmental conditions
the loss of luster due to exposure to air and/or moisture
ability to oxidize with water
Examples of Chemical Properties
• Chemistry is the study of • the composition/properties of matter• the changes that matter undergoes
Chemistry Defined
Changes in Matter
There are two basic ways matter can change: 1.) Physically2.) Chemically
Quiz time!
• What type of change is most likely occurring here?
• How do you know?
Think F.A.R.T.S. and Fireworks!
Quiz time!
• What type of change is most likely occurring here?
• How do you know?
Quiz time!
• What type of change is most likely occurring here?
• How do you know?
In order for matter to chemically change......A CHEMICAL REACTION MUST TAKE PLACE.
Chemical Reactions are Everywhere
Cooking Baking
Chemical Reactions are Everywhere
Hair DyeAuto Fuel
Chemical Reaction Defined
Process in which matter chemically changes because two or more substances react to form new substances
How do you know when a chemical reaction takes place?Color Change Precipitate (Solid) Formation
How do you know when a chemical reaction takes place?Gas Formation Odor
How do you know when a chemical reaction takes place?
Temperature Change Change in Acidity
Evidence that Matter is Chemically Changing Due to a Chemical Reaction
F.A.R.T.S.?!?!?!?
When You Eat a Slice of PizzaReactants Summarized Products SummarizedBreadCheeseToppings of ChoiceTomato Sauce
59% Nitrogen21% Hydrogen9% Carbon dioxide7% Methane4% Oxygen1% Hydrogen sulfide gas
• Fizzing/Bubbles• Formation of gas
• Aroma• Replacement• Temperature• new Substance(s)
• Formation of a solid
• Sound• Light• Color Change
Fireworks!
Evidence that Matter is Chemically Changing Due to a Chemical Reaction
New substances will have completely different properties than the orignial substances
What evidence proves that new substancesformed during our demonstration?
+ +
New Substance(s) Form During a Chemical Reaction
New substances will have completely different properties than the orignial substances
What if you are unable to observe the properties of the new substances? Or, what if the properties look like the reactants?
LiquidColorlessOdorless
LiquidColorlessOdorless
SolidYellow
Denser than liquid
Chemical Equations: used to show chemical reactions, and to prove that new substances form during a reaction
• Reactants: substance(s) at the beginning of the reaction; left side of arrow
• Products: substance(s) at the end of the reaction; right side of arrow
Exploding Pumpkin
Reactants ProductsCaC2(s) + 2H2O(l) → Ca(OH)2(s) + C2H2(g)
Modeling Chemical Reactions
Exploding Pumpkin
Exploding Pumpkin
Reactants Products
Name Calcium Carbide Water Calcium Hydroxide Acetylene Gas
Properties
PowderSolidGray
Highly Reactive
ColorlessOdorless
Liquid
Powdered Solid
White
FlammableGas
ColorlessOdorless
+ +
CaC2(s) + 2H2O(l) → Ca(OH)2(s) + C2H2(g)
+ +
Symbols Used in Chemical Equations
Symbol Purpose
2H2O Example of a chemical formula; identifies substances in the reaction and the amount needed for reaction to occur
+ Separates more than one reactant or product; say plus
Separates reactants from products; indicates direction of reaction; say yields (makes)
(s) Identifies a solid state
(aq) Identifies a substance that is dissolved in water; aqueous solution
(l) Identifies liquid state
(g) Identifies gas state
CaC2(s) + 2H2O(l) → Ca(OH)2(s) + C2H2(g)