Matter

www.middleschoolscience.com 2008

Mass vs. WeightMass

• a measure of how much matter an object is made of

• does not change, regardless of where something or someone is

Weight

• the force of gravity on an object

• equal to the mass of the body times the local acceleration of gravity

http://www.exploratorium.edu/ronh/weight/index.html

Why do you think

the person’s weight is

less on the moon?

Mass = 59 kg Mass = 59 kg

Weight = 579 N Weight = 96 N

•Anything that has a mass and a volume

Matter

Note……. Fire is NOT an example of matter

Close up view of atoms and their behavior

Animated images are from http://www.chem.purdue.edu/gchelp/

Physical Properties of Matter•any property of matter that can be

observed or measured without changing the identity of the matter

•Examplestemperature

color shapetaste

state/phasedensity

D = m V

Chemical Properties of Matter•any property of matter that describes a

substance based on its ability to change into a new substance

•Examplesflammability

reactivity with vinegarreactivity with oxygen

Iron + Oxygen Iron oxide (rust)2Fe + 3O2 Fe2O3

Comparing Physical and Chemical Properties

Substance/Matter Physical Property Chemical Property

Helium Less dense than air Nonflammable

Wood Grainy texture Flammable

Baking soda White powder Reacts with vinegar to produce bubbles

Powdered sugar White powder Does not react with vinegar

Rubbing alcohol Clear liquid Flammable

Red food coloring Red color Reacts with bleach and loses color

Iron Malleable Reacts with oxygen

Chemical or Physical Property?1. Paper is white

2. Boiling point of H2O is 100oC

3. Zinc reacts with hydrochloric acid and creates hydrogen gas

4. Nitrogen does not burn

5. Sulfur smells like rotten eggs

_____________ Property

_________________ Property

__________________ Property

__________________ Property

__________________ Property

•Changing from one state to another is a Physical Change.

•If a new substance is formed it is a Chemical Change.

Images are from http://www.chem4kids.com

Physical Change•a change in shape, size, color, or state•a change without a change in chemical

composition•a change that is reversible

▫The Mixtures Lab•Examples

tearing paper cutting your hair change in state

Chemical or Physical Change?1. Bending a Paper Clip

2. Baking a cake

3. The sublimation of carbon dioxide

4. Crushing an aluminum can

5. Vinegar and baking soda combining to create salt and water

Physical Change

Chemical Change

Chemical Change

Physical Change

Physical Change

States of Matter Continuum

Taken from: http://www.chem4kids.com/files/matter_becondensate.html

Density•a measure of the amount of matter

present in a given volume of a substance• typically expressed in the following units:

▫grams per cubic centimeter (g/cm3) for solids

▫grams per milliliter (g/ml) for liquids•can change as temperature and pressure

change

Which do you think is more dense? Why?

Calculating Density•Density can be calculated by dividing

the mass of an object by its volume

D = m V

Sample ProblemTimothy found a solid metal blockthat has a mass of 100 grams and a volume of 25 cm3. What would be

the density of the block?

D = =

100 grams25 cm3

4 grams cm3

Practice Problems1. Find the density of a substance with a mass

of 27 g and a volume of 7 cm3.

2. A block of maple has a mass of 20 grams and a volume of 26.5 cm3. What is the density of the block?

D = m V

D = m V

D =

=27 g7 cm3

3.86 grams cm3

D =

20 grams26.5 cm3

= 0.75 grams cm3

• The building blocks of Matter• Consists of Protons (+), Electrons (-), and Neutrons (N).

• Consists of only one kind of atom, • Cannot be broken down into a simpler type of matter by either physical or chemical means• Can exist as either atoms or molecules.

Images are from http://www.chem4kids.com

• A molecule consists of two or more atoms of the same element, or different elements, that are chemically bound together. • In the animation above, two nitrogen atoms (N + N = N2) make one Nitrogen molecule .

Animated images and notes from http://www.chem.purdue.edu/gchelp/atoms/elements.html

• Atoms of two or more different elements bound together.

• Can be separated into elements chemically, but not physically.

In the animation above, water (H20) is a compound made of Hydrogen and Oxygen.

• Solutions are groups of molecules that are mixed up in a completely even distribution.

• Uniform Distribution.• Example: Sugar and Water

Images are from http://www.chem4kids.com

• The substance to be dissolved.

• The one doing the dissolving.

Images are from http://www.chem4kids.com

• Particle sizes are in between the size of particles found in solutions and suspensions .

• Can be mixed and remain evenly distributed without settling out.

• They are substances held together by physical forces, not chemical.

• Can be separated physically.

• Solutions are also mixtures.

• The substances are not uniformly mixed.

• Example: Sand in a glass of water.Images are from http://www.chem4kids.com

• Are heterogeneous mixtures consisting of parts that are visible to the naked eye.

Example: the ingredients in salad dressing

• Substances will settle over time.

Strange Science

http://www.strangematterexhibit.com/structure.html