Matter: Properties & ChangeMatter: Properties & Change

Physical propertiesPhysical properties Physical properties can be observed or

measured without changing the identity of the matter.

Basically, properties you notice when using one of your five senses: Feel - mass, volume, texture Sight - color Hear Smell Taste

Physical properties of matter are categorized as either: Intensive or Extensive:

Intensive - Properties that do not depend on the amount of the matter present.

Color Odor Luster - How shiny a

substance is. Malleability - The ability of a

substance to be beaten into thin sheets.

Ductility - The ability of a substance to be drawn into thin wires.

Conductivity - The ability of a substance to allow the flow of energy or electricity.

Hardness - How easily a substance can be scratched.

Melting/Freezing Point The temperature at which the solid and liquid phases of a substance are in equilibrium at atmospheric pressure.

Boiling Point - The temperature at which the vapor pressure of a liquid is equal to the pressure on the liquid (generally atmospheric pressure).

Density is a very important property.It is the amount of matter in a given volume.

Density = Mass / Volume

More Physical PropertiesMore Physical Properties

A. Physical PropertiesA. Physical Properties

Physical properties can be described as one of 2 types:

Extensive Propertydepends on the amount of matter

present (example: length)

Intensive Propertydepends on the identity of substance, not

the amount (example: scent)

B. Extensive vs. IntensiveB. Extensive vs. Intensive

Examples:boiling point

volume

mass

density

conductivity

intensive

extensive

extensive

intensive

intensive

Extensive - Properties that do depend on the amount of matter present.

Volume - A measurement

of the amount of space a substance occupies.

*Length

V is for VolumeV is for Volume

Briefly, volume is the amount of space something takes up.

Whether it’s a speck of dust or Jupiter, all matter takes up space.

Measuring the volume of…Measuring the volume of…

Liquids:Graduated cylinderDisplacement methodMeasured in liters (L) &

milliliters (mL)Solids:

Length x width x heightGases:

Since a gas expands to fill its container, if you know the volume of the container, you know the volume of the gas.

Density - The mass of a substance divided by its volume

Density is an important physical property. Density is the mass of a substance per unit volume.

Volume is the amount of space an object occupies.

C. Density – a physical propertyC. Density – a physical property

Derived units = Combination of base units

Volume (m3 or cm3 or mL) length length length Or measured using a

graduated cylinder

D = MV

1 cm3 = 1 mL1 dm3 = 1 L

Density (kg/m3 or g/cm3 or g/mL) mass per volume

C. DensityC. Density An object has a volume of 825 cm3 and a

density of 13.6 g/cm3. Find its mass.

GIVEN:

V = 825 cm3

D = 13.6 g/cm3

M = ?

WORK:

M = DV

M = (13.6 g/cm3)(825cm3)

M = 11,220 g

M = 11,200 gV

MD

C. DensityC. Density A liquid has a density of 0.87 g/mL. What

volume is occupied by 25 g of the liquid?

GIVEN:

D = 0.87 g/mL

V = ?

M = 25 g

WORK:

V = M D

V = 25 g

0.87 g/mL

V = 29 mLV

MD

= 28.736 mL

Physical Properties - Physical Properties - ExamplesExamples

Other physical properties include: Color Hardness Odor Taste State of matter Texture Luster (shine) Flexibility Heat conductivity Electrical conductivity Solubility (ability to dissolve in water.) Shape Viscosity Ductility Malleability

D. Chemical PropertiesD. Chemical PropertiesChemical Property

describes the ability of a substance to undergo changes in identity

Chemical propertiesChemical properties

A common chemical property is reactivity.Reactive to oxygenReactive to airReactive to water…

Notice that chemical properties aren’t EASY to observe, unlike physical properties.

Chemical properties - Chemical properties - ExamplesExamples

Examples of chemical properties include: The ability to burn Ability to tarnish Ability to rust Ability to decompose Ability to react with

other chemicals Instability Ability to do acid/base

reactions

Physical vs. ChemicalPhysical vs. Chemical

Physical properties: observe without changing the identity of the substance

Chemical properties: observe only when the identity changes

How do you know if it is chemical or physical?If it CHanges, it’s CHemical

E. Physical vs. Chemical PropertiesE. Physical vs. Chemical Properties

Examples:melting point

flammable

density

magnetic

tarnishes in air

physical

chemical

physical

physical

chemical

Chemical and physical Chemical and physical properties – So what?properties – So what?

Titanium is very strong and doesn’t rust, so it is often used in jet engines.

Titanium is also nonallergenic. This, combined with the fact that it is rust proof makes it great for artificial joints as well as piercings.

Chemical and physical Chemical and physical properties – So what?properties – So what?

Tungsten is usually used as the filament in lightbulbs because it has the highest melting point of any metal.

It glows red hot when electricity runs through it, and it gives off both heat and light.

Chemical and physical Chemical and physical properties – So what?properties – So what?

Vanadium is heavier and harder than titanium, so mixing a tiny bit of vanadium with steel can make cheap tools that are still very strong.

Chemical and physical Chemical and physical properties – So what?properties – So what?

Helium is almost completely nonreactive (inert).

It is lighter than air, so it’s great for floating balloons (or making funny voices.)

When electricity runs through helium, it glows a creamy pale peach color.

Chemical and physical Chemical and physical properties – So what?properties – So what?

In 1943, all US pennies were made of zinc plated steel because copper was being used in the war. The pennies had to be coated with zinc because steel will rust, but zinc won’t.

Chemical and physical Chemical and physical properties – So what?properties – So what?

Sulfur smells awful. Rotten eggs, onions, and garlic all have sulfur in them. Stink bombs use sulfur to create a bad smell.

Sulfur is also flammable, and it is one of the 3 main ingredients in gun powder.

Chemical and physical Chemical and physical properties – So what?properties – So what?

Chromium is famous for its intense luster. Chrome plated tools, jewlery, silverware, or car parts are very popular.

Chemical and physical Chemical and physical properties – So what?properties – So what?

Most bullets are made of lead because lead is a very dense metal. These bullets are required, by international law, to be coated with a different metal because lead has such a low melting point and is so malleable.

Chemical and physical Chemical and physical properties – So what?properties – So what?

The most dense elements are Iridium and osmium which have a density of about 22.6 g/cm3

Physical ChangePhysical Change

A Physical change is a change in a substance that does not change what the substance is.

Physical Change - examplesPhysical Change - examples

Examples of physical change include: Change in shape Change in size Change in phase

Melting (solid to liquid) Boiling (liquid to gas) Evaporation (liquid to gas) Condensation (gas to liquid) Freezing (liquid to solid) Sublimation (solid to gas) Deposition (gas to solid)

Physical ChangePhysical Change

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

(change in phase) squishing

Physical ChangePhysical 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

Chemical changeChemical change

A chemical change is a change in which a substance is changed into a different substance. (You’ve changed what it is.)

Chemical changeChemical change Examples of

chemical changes include: Burning Rusting Tarnishing Decomposing Polymerization

Chemical changeChemical change

Chemical changes occur when a chemical reaction causes bonds between atoms to break or to form.

Chemical change – Chemical Chemical change – Chemical reactionsreactions

There are 5 types of chemical reactions that cause chemical changes to occur.

Chemical change – Chemical Chemical change – Chemical reactionsreactions

1- Composition reactions Two things come

together to form something new

A + B = AB 2H2 + O2 2H2O

Chemical change – Chemical Chemical change – Chemical reactionsreactions

2- Decomposition reactions 1 thing breaks apart

to form 2 or more things.

AB = A + B 2H2O 2H2 + O2

Chemical change – Chemical Chemical change – Chemical reactionsreactions

3- Single replacement reactions One atom replaces

another atom A + BC = AC + B

orA + BC = AB + C

Mg + 2HCl H2 + MgCl2

Chemical change – Chemical Chemical change – Chemical reactionsreactions

Double replacement reactions Two chemicals

switch places AX + BY = AY + BX 2KI + Pb(NO3)2

PbI2 + 2KNO3

Chemical change – Chemical Chemical change – Chemical reactionsreactions Combustion

reaction A substance

combines with oxygen and releases energy.

C3H8 (propane) + 5O2 3CO2 + 4H2O

Chemical Change: EvidenceChemical Change: Evidence

Evidence that a chemical change has occurred might include: A color change An odor change Formation of a precipitate

(you mix two liquids and make a solid)

Gas is formed (bubbles) Changes in physical

properties.

Physical and Chemical Physical and Chemical changechange

During a chemical change energy can be released in the form of: Heat Light

Physical and Chemical Physical and Chemical change - heatchange - heat

A chemical reaction that releases energy in the form of heat is called exothermic. Heat comes OUT

Exo = out Thermic = heat

It will feel HOT.

Physical and Chemical Physical and Chemical change - heatchange - heat

A chemical reaction that absorbs energy in the form of heat is called endothermic. Heat goes IN

Endo = in Thermic = heat

It will feel COLD

I. Law of Conservation of MassI. Law of Conservation of Mass

Although chemical changes occur, mass is neither created nor destroyed in a chemical reaction

Mass of reactants equals mass of products

massreactants = massproducts

A + B C

I. Conservation of MassI. Conservation of Mass In an experiment, 10.00 g of red mercury (II) oxide powder is

placed in an open flask and heated until it is converted to liquid mercury and oxygen gas. The liquid mercury has a mass of 9.26 g. What is the mass of the oxygen formed in the reaction?

Mercury (II) oxide mercury + oxygenMmercury(II) oxide = 10.00 gMmercury = 9.26Moxygen = ?

GIVEN:Mercury (II) oxide mercury + oxygen

Mmercury(II) oxide = 10.00 g

Mmercury = 9.86 g

Moxygen = ?

WORK:10.00 g = 9.86 g + moxygen

Moxygen = (10.00 g – 9.86 g)

Moxygen = 0.74 g

massreactants = massproducts