C HEMICAL AND P HYSICAL R EACTIONS. P HYSICAL P ROPERTIES A characteristic of matter that can be observed without changing the substance into another.

CHEMICAL AND PHYSICAL

REACTIONS

PHYSICAL PROPERTIES A characteristic of matter that can be

observed without changing the substance into another substance

Examples: Freezing Boiling Melting Hardness Color Shine flexibility Solubility

CHEMICAL PROPERTIES Characteristics of a substance that describe

its ability to change into a new substance

Examples: Burning Rusting Tarnishing

Changing into a new substance requires another chemical, like O2 changing to CO2

PHYSICAL AND CHEMICAL PROPERTIES ACTIVITY Using the objects provided, list the physical

and chemical properties of each object

Create a table to classify each object based on its properties

Use the equipment & substances available

A: Salt B: Crayon C: Antacid

Physical or chemical?

Reacts with water

Yes or no?

Does not react

Soluble

Not soluble

Hard

Soft

Color

Reacts with vinegar

Does not react with vinegar

Physical Properties or Chemical PropertiesMetallic, non-metallic, magnetic, heat

conductor

PHYSICAL AND CHEMICAL PROPERTIES ACTIVITY 2 Using the substance provided, investigate

and report on its chemical and physical properties

Use your Lab Book, create a table with Physical and Chemical Properties noted

PHYSICAL CHANGES The form or appearance of a substance is

altered, without combining it with another substance

Examples?

Ice to water to steam Ice cream melts Make Kool-aid Cut paper

Reversible!!!

CHEMICAL CHANGES A change in matter that results in one or

more new substances

Chemical in the original substance combines with another chemical to create a new substance

Examples? Burning anything Baking cookies Fireworks

Not reversible!!!

EVIDENCE OF CHEMICAL REACTIONS Color change

Heat given off/absorbed

Change in odor

Gas released

Light given off

Precipitate

CHANGES IN ENERGY Is energy released/taken in during a physical

or chemical change?

Energy can be light, heat, or sound

If heat energy is removed during a reaction, it is an exothermic reaction (feels hot)

If energy is added during a reaction, it is an endothermic reaction (feels cold)

COMMON CHEMICAL REACTIONS Photosynthesis

CO2 + H2O = C6 H12 O6 + O2

Respiration O2+ H2O = CO2 + H2O

Combustion

Rusting

MINI-LAB! Determine whether each reaction is

endothermic or exothermic

Make hypotheses for each of the following: Strike a match Vinegar and antacid

Write 3 observations for each

Write a one sentence conclusion for each

RATES OF CHEMICAL REACTIONS How quickly a chemical reaction can

take place

Controlled by 4 thingsSurface AreaTemperatureConcentrationSubstances

CatalystsInhibitors

REACTANTS AND PRODUCTS Reactants are combined together to create

products

What are the reactants and products in the following equations? C + 2 O CO2

2 H + O H2O

What do you notice about these equations? There are the same number of atoms on the left as

on the right Coefficients, subscripts

CHEMICAL EQUATIONS Label the chemical equation below:

CaCO3 CaO + CO2

TYPES OF REACTIONS Synthesis

Start with 2 or more elements or compounds and combine them to make something more complex

Decomposition Start with 1 compound and break it down to form

2 or more elements or compounds

Replacement Elements trade places in a reaction

CONSERVATION OF MASS You must end up with the same amount you

started with

Mass cannot be created or destroyed

WARM-UP-ON YOUR OWN PAPERWRITE WHETHER EACH REACTION IS SYNTHESIS, DECOMPOSITION, OR REPLACEMENTMg + O2 MgO2H2O2 2 H2O + O2

2Cu2O + C 4Cu + CO2

FeS + 2HCl FeCl2 + H2SP4O10 + 6H2O 4H3PO4

Fe2O3 + C Fe + CO2

SO2 + O2 SO3

BALANCING EQUATIONS Goal- Have the same number of atoms on

both sides of the equation.

Rules Coefficients multiply You can not change subscripts If there is no subscript after an atom, then you

know there is only 1 atom present

Examples on board Practice worksheet