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)