Chemical and Physical

Reactions

http://www.bing.com/videos/search?q=Bill+Nye+Chemical+Reactions+Full+Episode&Form=VQFRVP#view=detail&mid=B6929A663E2BC750BEF4B6929A663E2BC750BEF4

Click on link – choose the Bill Nye 7F – simple chemical reactionsThat is 23 minutes long.

Physical Properties: characteristics of matter that can be observed without changing it to another substance.

Examples: _________ (mass/volume) ________ (can pulled into wires)

__________ (how easy it breaks) __________ (how stretchy)

_____________ (lets light through)

(Phase change)

Density Ductility

Brittleness Elasticity

Transparency

Boiling / freezing points

Physical ChangesIn a physical change, the substances are not altered chemically. No new products are formed. Chemical bonds are not broken in a physical change.

Usually Reversible

Examples Mixtures

Change shape

Phase changes

Make Kool-aid or lemonade

Ice to water to steamIce cream melts

Cutting (paper, trees, etc) Break Glass

Physical Change

• Physical changes might be caused by:– Grinding– Cutting– Crushing– Bending– Breaking– Heating/cooling

• (change in phase)

– squishing

Physical Change

• Evidence that a physical change has occurred might include:– Change in shape– Change in form– Change in size– Change in phase (This is

always a physical change!)

Physical changes are usually reversible

Physical change• What could you do to

these items to cause a physical change to occur?

Chemical Properties Characteristics of matter that describe its ability to change into a new substance

Examples: _________________________ (ability to burn) ___________________(the ability to react with oxygen, which causes apple slices to turn brown and iron to rust) _________________________________(reacts to form new substance)

flammability

Ability to rustOxidation

Reactivity with acid

A change in matter that results in one or more new substances. You change what it is.

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

Chemical Changes

Evidence of Chemical Reactions or Change

https://www.youtube.com/watch?v=cZMkqagL8Ps (2:52) Evidence of a Chemical Reactions

Evidence of Chemical Change

• New ________appears

• Bubbbles or ________

• Precipitate forms (____ material)

• _____ is produced

• ______ is produced

• ______ is given off

• Difficult or impossible to __________

color

fizzing

solid

reverse

Heat

Light

Sound

Reactions with Acid

Vinegar + baking soda = release of Carbon Dioxide Gas

Reactions with Oxygen OXIDATION

Iron + Oxygen = rust

Reactions with Electricity Silver Plating

Reactions between Substances Sodium + chloride = salt

Silver + sulfer in the air = tarnish

Other Examples►Wood burning►Metal rusting►Food digesting►Gasoline burning►Cake baking

https://www.youtube.com/watch?v=M8tyjwB42X4 (3:18) chemical and physical changes with molecules and formulas Review

Physical or Chemical Change?

►Water evaporates from the ocean.

Physical

Physical or Chemical Change?

►The yolk of an egg, which contains sulfur, causes tarnish to form on silver.

Chemical

Physical or Chemical Change?

►The ice on a lake melts to become water in the lake.

Physical

Physical or Chemical Change?

►Charcoal in a fire turns to ash after several hours.Chemical

Physical or Chemical Change?

►A pencil is sharpened in a pencil sharpener, leaving behind shavings. Physic

al

Physical or Chemical Change?

►A battery makes electricity to turn on a flashlight.

Chemical

Physical or Chemical Change?

►A bicycle rusts when left in the rain.

Chemical

Physical or Chemical Change?

►A shirt is accidentally torn in the washing machine.

Physical

Physical or Chemical Change?

►A log is split in two by an axe.

Physical

Changes in EnergyChemical change = Chemical reactions

• When a chemical change occurs, energy is either released or absorbed.

Chemical change - heat If heat energy is

released during a reaction, it is an exothermic reaction (feels hot).

EXO = release, outside, gives off – Heat comes OUT

• Exo = out• Thermic = heat

Heat is given off. Examples:

Burning paper, hand warmers, fire

If heat energy is absorbed (added) during a reaction, it is an endothermic reaction

ENDO = absorb, take in– Heat goes IN

• Endo = in• Thermic = heat

Examples: Cold packs baking cookies (heat must be added)

Mini-Lab! Copy chart on your own paper.

ItemPhysical

PropertiesObserved

ChemicalProperties

Exothermic orEndothermic

Reaction

Match

Vinegar&

Baking Soda

Water&

Baking Soda

Vinegar&

Alkaseltzer

Water&

Alkaseltzer

STATES OF MATTER

http://www.teachertube.com/viewVideo.php?video_id=274943

http://www.harcourtschool.com/activity/states_of_matter/index.htmlSimulation activity

Gas matter that has no definite volume or shape. Molecules of a gas are so loosely arranged and move so rapidly that they will fill their container.

Liquid matter that has definite volume but not shape. Since the molecules of a liquid are loosely packed and move with greater speed, a liquid can flow and spread.

Solid matter that has definite volume and shape. The molecules are packed together tightly and move slowly.

Phase change is a physical property of matter

Changing the amount of heat energy usually causes a temperature change.

During a phase change energy is directed to making the phase change so the

temperature does not change

Do the following simulations with this linkhttp://www.harcourtschool.com/activity/hotplate/index.html

   _____________ the change from solid to liquid.  _____________ the change from liquid to solid.  ______________ the change from liquid to gas.  ______________ vaporization from the surface of a liquid.  ______________ vaporization from within as well as from the

surface of a liquid. ________________ the change from gas to liquid.  _________________ the change from solid to gas.  _________________ the change from gas to solid.  

Melting

Freezing

Vaporization

Evaporation

Boiling

Condensation

Sublimation

Deposition

Show computer graphic