Introduction to Chemical Reactions. Learning Targets Be able to interpret Chemical Equations. Be able to interpret Chemical Equations. Be able to balance.

Introduction to Introduction to Chemical ReactionsChemical Reactions

Learning TargetsLearning Targets

Be able to interpret Chemical Be able to interpret Chemical Equations.Equations.

Be able to balance Chemical Be able to balance Chemical Equations.Equations.

Prove The Law of Conservation Prove The Law of Conservation of Mass showing that matter is of Mass showing that matter is never created or destroyed in a never created or destroyed in a chemical reaction. chemical reaction.

Representing Chemical ReactionsRepresenting Chemical Reactions

Chem rxns are a way to represent or Chem rxns are a way to represent or model what is happening in a chemical model what is happening in a chemical equationequation

Solid Sodium combines with Chlorine gas Solid Sodium combines with Chlorine gas to make solid Sodium Chloride:to make solid Sodium Chloride:

2Na 2Na (s) (s) + Cl+ Cl22 (g) (g) 2NaCl 2NaCl(s)(s)

Symbol Purpose

+ Separates more than one reactant or product

Separates reactants from products. Indicates direction of

reaction(s) Identifies a solid state

(aq) Identifies that something is dissolved in water

(l) Identifies liquid state

(g) Identifies gaseous state

∆

Heat is needed for rxn

Pt

A catalyst is needed

Law of Conservation of MassLaw of Conservation of Mass

In a chemical reaction, matter is neither In a chemical reaction, matter is neither created nor destroyed. created nor destroyed.

Atoms won’t change their identity (e.g. a Atoms won’t change their identity (e.g. a Carbon atom can’t become an Iron atom)Carbon atom can’t become an Iron atom)

Must have the same number of each type Must have the same number of each type of atom on both sides of the chemical of atom on both sides of the chemical equation. equation.

Conservation of Mass Video

Steps to Balancing a Chemical EquationSteps to Balancing a Chemical Equation

Don’t change the polyatomic Don’t change the polyatomic ions – put a square around ions – put a square around them if it helps – Think of it as them if it helps – Think of it as ONE unit.ONE unit.Don’t change subscripts. They Don’t change subscripts. They tell you how many atoms are in tell you how many atoms are in a molecule a molecule

CC66HH2222OO1111

CaClCaCl22 + AgNO + AgNO33 AgCl + Ca(NO AgCl + Ca(NO33))22

FeFe22OO33 + H + H22SOSO44 Fe Fe22(SO(SO44))33 + H + H22O O

Chemical Reactions are Chemical Reactions are EverywhereEverywhere

CookingCooking RespirationRespiration

Chemical Reactions are Chemical Reactions are EverywhereEverywhere

Dying your hairDying your hair Driving your carDriving your car

How do you know when a How do you know when a chemical reaction takes chemical reaction takes place?place?

Color ChangeColor Change

Formation of a Formation of a PrecipitatePrecipitate

How do you know when a How do you know when a chemical reaction takes chemical reaction takes placeplace??

Gas FormationGas Formation OdorOdor

How do you know when a How do you know when a chemical reaction takes chemical reaction takes place?place?

Temperature ChangeTemperature Change Change in AcidityChange in Acidity