Changing MatterPhysical & Chemical Changes

What different ways can we differentiate between people?

PropertiesHow we identify something.

Matter has properties

Two basic types of properties that we can associate with matter.

Physical properties

Chemical properties

Physical Properties

Anything that can be observed without changing the identity of the substance. (Tends to be measurable.)

MalleabilityMalleability• The ability of an object to be molded into different shapes.

– Example – metals.

Opposite – Brittle, not flexible.

DuctilityDuctility• The ability of an object to be drawn into thin wires without

losing strength.– Metals are ductile.

Chemical PropertiesThe way a substance may change or react to form other substances

Combustion - the process of burning something

Matter can be changed two ways

Physically Physical reaction

Physical change

Chemically Chemical reaction

Chemical change

Physical Changes

Do NOT CHANGE THE TYPE OF MATTER

Nothing new or different is formedCould be a change in:

Mass Volume Density Change in state Color Shape

Size

Substance may seem different, but the way the atoms link up is the same.

It changes phase (freezes, boils, evaporates, condenses, sublimates)

Physical Changes

Examples of Physical Changes

Boiling Freezing Dissolving Breaking Making a mixture

2 or more types of matter (substances) mixed together Not in specific amounts Can be separated physically

Chemical ChangesChemical changes, or chemical reactions, are changes that result in the production of another substance. Changes the way the molecules link up (chemical composition)Makes new substances (new compounds, or compounds are broken down into the elements that make them up)

The substances present at the beginning of the change are not present at the end; new substances are formed. The change cannot be “undone.”

Chemical Changes

Evidence of a chemical reactionFormation of gas Formation of precipitate Change in color Change in energy (temperature)

Endothermic Absorbs heat energy (gets cold) Exothermic Releases heat energy (gets hot)

Chemical Changes

Atoms are re-arranged, NOT created or destroyed

It’s a chemical change if….

It burns

Temperature changes without heating/cooling

It’s a chemical change if….

It bubbles (makes a gas)

It’s a chemical change if...

It changes colorIt forms a precipitate – (solid that forms from two liquids).

Again signs that a Again signs that a Chemical Change has Chemical Change has

occurredoccurredCreation of a gas (bubbles)Creation of a gas (bubbles)Creation or loss of heatCreation or loss of heatFireFireRottingRottingBreaking down (decomposition)Breaking down (decomposition)Precipitation (Sour milk clumps)Precipitation (Sour milk clumps)CookingCookingRusting (oxidation)Rusting (oxidation)

Chemical Change

The only TRUE sign that a chemical change has taken place is the formation of a new substance.

A new substance that was not there before.

A new substance with a new chemical composition (Atoms are arranged differently).

Basically What You’re Basically What You’re Telling Me Is…Telling Me Is…

If you end up with a If you end up with a chemical or chemical or chemicals that you chemicals that you did not start with, did not start with,

It is a It is a chemical chemical change!!!!!!!change!!!!!!!

Another Example Another Example Is…Is…

Eating…Eating…

Now eating can change food Now eating can change food both physically and both physically and chemically.chemically.

Chewing is Physical but…Chewing is Physical but…

Once the food touches the Once the food touches the chemicals in the saliva begin chemicals in the saliva begin to change the food to change the food chemically.chemically.

Law of Conservation of Matter

Matter is conserved type of atoms does not change

Nothing is created or destroyed

Law of Conservation of Mass

Mass is conserved amount of atoms cannot change

Nothing is created or destroyed

What kind of change is it if someone...Tears up paper?

Physical changeMixes salt and water?Physical change

What kind of change is it if someone...Burns paper?

Chemical changeEvaporates salt water?Physical change

What kind of change is it if someone...Mixes vinegar and

baking soda?Chemical change

Physical and Chemical Physical and Chemical Changes Quiz ……….True Changes Quiz ……….True

or False??or False?? 

1. With a physical change, no new substance is formed.  

2. With a chemical change, a chemical reaction occurs.

3. With a physical change, energy is either given off or absorbed.

4. A chemical change can be easily reversed.5. Eating food can be considered both physical

and chemical changes.

Physical and Chemical Physical and Chemical Changes Changes

Quiz……….Answers!Quiz……….Answers!1. With a physical change, no new substance is formed.  TRUE

2. With a chemical change, a chemical reaction occurs. TRUE

3. With a physical change, energy is either given off or absorbed. FALSE

4. A chemical change can be easily reversed. FALSE

5. Eating food can be considered both physical and chemical changes. TRUE

ONLINE QUIZONLINE QUIZ

http://www.fordhamprep.org/gcurran/sho/sho/review/rev15b.htm

Physical or Chemical Change?

Painting Wood

PHYSICAL

Physical or Chemical Change?

•A ring tarnishing

•CHEMICAL

Physical or Chemical Change?Tarnish is a thin layer of corrosion that forms over copper, brass, silver, aluminum, magnesium and other similar metals as their outermost layer undergoes a chemical reaction. It causes to lose luster.

Physical or Chemical Change?

•Burning Paper

•CHEMICAL

Physical or Chemical Change?

•Digestion of food

•CHEMICAL

Physical or Chemical Change?

•Sugar dissolving in water

•PHYSICAL

Physical or Chemical Change?

•Iron turning red when heated

•PHYSICAL

Physical or Chemical Change?

•Evaporation

•PHYSICAL

Physical or Chemical Change?

•A pond freezing in winter

•PHYSICAL

Physical or Chemical Change?

•Melting ice

•PHYSICAL

Physical or Chemical Change?

•Cutting wire

•PHYSICAL

Physical or Chemical Change?

•Painting fingernails

•PHYSICAL

Physical or Chemical Change?

•Cutting fabric

•PHYSICAL

Physical or Chemical Change?

•Baking muffins

•CHEMICAL

Physical or Chemical Change?

•Shattering glass

•PHYSICAL

Physical or Chemical Change?

•Decomposition of old leaves

•CHEMICAL

Physical or Chemical Change?

•Wrinkling a shirt

•PHYSICAL

Physical or Chemical Change?

•An old nail rusting

•CHEMICAL