CATALYST

• Demonstrate knowledge of bonding through a quiz.

• Identify the parts of a chemical equation.

What is the difference between

a physical and a chemical change?

OBJECTIVES

DATE: 02/25/2015

REMINDERS

• Chemical Equation Practice–Page 284 #1-3

Engineering Week

• Monday: Electronic Breakdown• Tuesday: Egg Drop Challenge• Wednesday: Build a Lightbulb

(Resume Workshop)• Thursday: Fling Machine• Friday: Light Soldering

Physical Change

• Changes to a substance that do not result in new types of molecules.• The chemical formula remains

the same.

• Changes in a substance that involve atoms rearranging to form new molecules.• There is a change in the chemical

formulas!

Chemical ChangeReaction

How can you tell if a chemical reaction is occurring?

• Gas formation

How can you tell if a chemical reaction is occurring?

• Precipitate (solid)

How can you tell if a chemical reaction is occurring?

• Color Change

Chemical Equations

• A model to represent what is happening during a chemical reaction.

Chemical Equations

2 NaCl (s)

2 NaF (s)

+ F2 (g) + Cl2 (g)

Symbols in Chemical EquationsSYMBOL

PURPOSE

+ Separates more than one reactant or product

Separates reactants

from products. Indicates direction of reaction

(s) Identifies a solid state

Symbols in Chemical Equations

SYMBOL

PURPOSE

(aq)Identifies that

something is dissolved in water

(l) Identifies liquid state

(g)Identifies gaseous

state

Write the word equation for the following chemical equation.

2 NaCl (s)

2 NaF (s)

+ F2 (g) + Cl2 (g)

2 molecules of solid sodium chloridereact with

1 molecule of fluorine gasto yield

2 molecules of solid sodium fluorideand

1 molecule of chlorine gas