Physical Properties of Physical Properties of MatterMatter

Mass versus WeightMass versus Weight

• Although the terms mass and weight are Although the terms mass and weight are used almost interchangeably, there is a used almost interchangeably, there is a difference between them. difference between them.

• MassMass is a measure of the quantity of matter, is a measure of the quantity of matter, which is constant all over the universe. which is constant all over the universe.

• Weight Weight is proportional to mass but depends is proportional to mass but depends on location in the universe. Weight is the on location in the universe. Weight is the force exerted on a body by gravitational force exerted on a body by gravitational attraction (usually by the earth). attraction (usually by the earth).

ExampleExample

• The mass of a man is constant. The mass of a man is constant. However the man may weigh: 150 However the man may weigh: 150 lbs on earth, 25 lbs on the moon lbs on earth, 25 lbs on the moon (because the force of gravity on the (because the force of gravity on the moon is 1/6 that of the earth), and be moon is 1/6 that of the earth), and be "weightless" in space. "weightless" in space.

Intrinsic PropertiesIntrinsic Properties

• do not depend on the amount of the do not depend on the amount of the sample being examined. sample being examined.

• Examples includeExamples include– ColorColor– Boiling PointBoiling Point– Melting PointMelting Point– DensityDensity– OdorOdor

• They cannot be changed without changing They cannot be changed without changing the object itself. the object itself.

Extensive PropertiesExtensive Properties

• depend on the quantity of the depend on the quantity of the sample sample

• Examples:Examples:– MassMass– VolumeVolume

• The object itself does not change if The object itself does not change if an extrinsic property changes. an extrinsic property changes.

Two Types of PropertiesTwo Types of Properties

• Chemical Properties: Properties that are Chemical Properties: Properties that are based on how a substance chemically based on how a substance chemically reacts with other substances.reacts with other substances.

• Physical Properties: Can be observed or Physical Properties: Can be observed or measured without changing the measured without changing the composition of matter. Physical composition of matter. Physical properties are used to observe and properties are used to observe and describe matter. describe matter.

Physical PropertiesPhysical Properties

• Physical propertiesPhysical properties include: include: – AppearanceAppearance– TextureTexture– ColorColor– OdorOdor– melting point and boiling pointmelting point and boiling point– DensityDensity– Solubility and polaritySolubility and polarity– and many others. and many others.

States of MatterStates of Matter

• Five basic states:Five basic states:– SolidsSolids– LiquidsLiquids– GasesGases– PlasmasPlasmas– Bose-EinsteinBose-Einstein

SolidsSolids

• A substance in a solid phase is relatively rigid, A substance in a solid phase is relatively rigid, has a definite volume and shape. has a definite volume and shape.

• The atoms or molecules that comprise a solid The atoms or molecules that comprise a solid are packed close together and are not are packed close together and are not compressible. compressible.

• Because all solids have some thermal energy, Because all solids have some thermal energy, its atoms do vibrate. However, this movement its atoms do vibrate. However, this movement is very small and very rapid, and cannot be is very small and very rapid, and cannot be observed under ordinary conditions. observed under ordinary conditions.

LiquidsLiquids

• Liquids have a definite volume, but are Liquids have a definite volume, but are able to change their shape by flowing. able to change their shape by flowing.

• Liquids are similar to solids in that the Liquids are similar to solids in that the particles touch. However the particles are particles touch. However the particles are able to move around. able to move around.

• Since particles are able to touch the Since particles are able to touch the densities of liquid will be close to that of a densities of liquid will be close to that of a solid. solid.

• Since the liquid molecules can move they Since the liquid molecules can move they will take the shape of their container.will take the shape of their container.

More on LiquidsMore on Liquids

• Viscosity --The resistance of a liquid to flow is Viscosity --The resistance of a liquid to flow is called its viscosity called its viscosity

• Surface Tension -- The result of attraction Surface Tension -- The result of attraction between molecules of a liquid which causes the between molecules of a liquid which causes the surface of the liquid to act as a thin elastic film surface of the liquid to act as a thin elastic film under tension. Surface tension causes water to under tension. Surface tension causes water to form spherical drops or a Menicus.form spherical drops or a Menicus.

• Vapor Pressure -- The pressure that a solid or Vapor Pressure -- The pressure that a solid or liquid exerts when it is in equilibrium with its liquid exerts when it is in equilibrium with its vapor at a given temperature. vapor at a given temperature.

• Boiling Point -- when vapor pressure = Boiling Point -- when vapor pressure = atmospheric pressure. (it turns into a gas)atmospheric pressure. (it turns into a gas)

GasesGases

• Gases have no definite volume or shape. Gases have no definite volume or shape. If unconstrained gases will spread out If unconstrained gases will spread out indefinitely. If confined they will take the indefinitely. If confined they will take the shape of their container. shape of their container.

• This is because gas particle have enough This is because gas particle have enough energy to overcome attractive forces.energy to overcome attractive forces.

• Each of the particles are well separated Each of the particles are well separated resulting in a very low density.resulting in a very low density.

PlasmaPlasma

• Plasma is an ionized gas, a gas into which Plasma is an ionized gas, a gas into which sufficient energy is provided to free sufficient energy is provided to free electrons from atoms or molecules and to electrons from atoms or molecules and to allow both species, ions and electrons, to allow both species, ions and electrons, to coexist. In effect a plasma is a cloud of coexist. In effect a plasma is a cloud of protons, neutrons and electrons where all protons, neutrons and electrons where all the electrons have come loose from their the electrons have come loose from their respective molecules and atoms, giving the respective molecules and atoms, giving the plasma the ability to act as a whole rather plasma the ability to act as a whole rather than as a bunch of atoms. than as a bunch of atoms.

More on PlasmaMore on Plasma

• Plasmas are the most common state Plasmas are the most common state of matter in the universe comprising of matter in the universe comprising more than 99% of our visible universe more than 99% of our visible universe and most of that not visible. and most of that not visible.

• Plasma occurs naturally and makes up Plasma occurs naturally and makes up the stuff of our sun, the core of stars the stuff of our sun, the core of stars and occurs in quasars, x-ray beam and occurs in quasars, x-ray beam emitting pulsars, and supernovas. emitting pulsars, and supernovas.

Even More on PlasmaEven More on Plasma

• On earth, plasma is naturally On earth, plasma is naturally occurring in flames, lightning and the occurring in flames, lightning and the auroras. auroras.

And now a fifth state -- And now a fifth state -- Bose Einstein?Bose Einstein?

• Recently, scientists have discovered the Recently, scientists have discovered the Bose-Einstein condensate, which can be Bose-Einstein condensate, which can be thought of as the opposite of a plasma. thought of as the opposite of a plasma.

• It occurs at ultra-low temperature, close to It occurs at ultra-low temperature, close to the point that the atoms are not moving at the point that the atoms are not moving at all. A Bose-Einstein condensate is a all. A Bose-Einstein condensate is a gaseous superfluid phase formed by atoms gaseous superfluid phase formed by atoms cooled to temperatures very near to cooled to temperatures very near to absolute zero. absolute zero.

DensityDensity

• Density of Solids and Liquids is Density of Solids and Liquids is determined by taking the mass in determined by taking the mass in Grams and dividing by the Volume in Grams and dividing by the Volume in mL or cmmL or cm33

• Density of Gases is determined by Density of Gases is determined by taking the mass in Grams and taking the mass in Grams and dividing by the volume in Ldividing by the volume in L

More on DensityMore on Density

• Density defined in a qualitative manner as Density defined in a qualitative manner as the measure of the relative "heaviness" of the measure of the relative "heaviness" of objects with a constant volume. objects with a constant volume.

• a physical property of matter, as each a physical property of matter, as each element and compound has a unique element and compound has a unique density associated with it. density associated with it.

• If we determine the density, we can If we determine the density, we can compare it to a known list and determine compare it to a known list and determine the substance.the substance.

Even More on DensityEven More on Density

• Objects that are less dense float.Objects that are less dense float.

• Objects that are more dense sink.Objects that are more dense sink.

• Water has a density of 1.0 g/mL.Water has a density of 1.0 g/mL.

• Objects less dense will floatObjects less dense will float

• Objects more dense will sinkObjects more dense will sink

Common DensitiesCommon Densities

MaterialMaterial Density (g/ml)Density (g/ml)

Pine WoodPine Wood 0.35 to 0.500.35 to 0.50

WaterWater 1.001.00

AluminiumAluminium 2.702.70

IronIron 7.807.80

Gold Gold 19.3019.30

MercuryMercury 13.513.5