MODULE C Lesson #2 States of Matter

OBJECTIVES At the end of this module, the

student will: Define terms associated with matter. List the three states of matter and

describe their characteristics. Compare and contrast the three states

of matter. Differentiate between a gas and a vapor. Describe how matter is classified. Explain how matter can be changed both

physically and chemically. Describe the methods for measuring

matter.

MATTER

What is Matter?

Matter is … anything that occupies space (has

volume) and has mass (weight). anything physically real that you can

see, touch or smell. the physical material that makes up

the universe.

A, Solid. B, Liquid. C, Gas

Simplified Models of the Three States of Matter.

SOLID

Defined shape Fixed volume Doesn’t flow Dense Not easily compressed High degree of internal order Strong attractive forces between atoms

called Van Der Waals forces Molecules fixed in relation to each other Motion limited to vibrations or back and

forth motion as if held by a spring

LIQUID

No definite shape Assumes the shape of the container Defined volume Flows (fluid) Moderate internal order, molecules

move more freely than solid Molecules farther apart than solid Still dense and resist compression Moderate expansion with heat

GAS

No definite shape Molecules minimally attracted with no

inherent boundaries Assumes the volume of its container Large expansion with heat Not dense and therefore easily

compressed and expanded No molecular order - molecular activity

is free, random and rapid with frequent collisions

Examples:

SOLID LIQUID GAS

IceRockScissorsPaperDry ice (CO2)

ButterCoffee beanIron

WaterOilGasolineJuiceCO2

ButterCoffeeMolten iron

Steam (vapor)

AirOxygenCOCO2

HeliumNitrogenArgon

Changing Matter

Physical change – During a physical change, physical properties change BUT the substance is still the same substance (i.e., freezing or boiling water)

Chemical change – During a chemical change, the chemical properties of substance change. (burning a candle) It becomes a new substance.

Physical or Chemical Change ?

When you get a can of icy soda on a hot day, water droplets begin to form on the outside of the can.

Physical or chemical change?

What is this process called?

Physical or Chemical Change?

The water level on your swimming goes down and you need to keep adding fresh water all summer. Where did the water go?

Physical or chemical change? _______

Changes of State

Melting Point The temperature at which a solid

changes to a liquid. Freezing Point

The temperature at which a liquid changes to a solid.

Boiling Point The temperature at which a liquid

changes to a gas

More Changes of State Condensation:

Change of state from a gas to a liquid. Evaporation:

The change in state of a substance from its liquid to its gaseous form occurring below its boiling point.

Vapor – Substance in the gaseous form that is normally a liquid at room temperature. (Water exists in both forms at the same time)

Sublimation: The change directly from the solid to the

gaseous state without becoming a liquid. Example: Dry Ice

ENDOTHERMIC: Change of state where heat is absorbed.

EXOTHERMIC: Change of state where heat is released.

Physical Change

States are usually changed by adjusting temperature.

First Law of Thermodynamics

Energy can never be created nor destroyed, only transformed in nature.

The transition from solid to liquid (and from liquid to gas) at the melting point (boiling point) is not instantaneous. There is a time delay for the conversion from one state to another at the same temperature as additional heat is needed from the environment. This heat is needed to overcome the

structured arrangement in a solid as it converts to a liquid (or in the liquid as it converts to a gas).

Latent Heats Also known as enthalpy.

Latent Heat of Fusion: The heat required to change a substance from a solid (ice) to a liquid (water) or vice versa.

Latent Heat of Vaporization: The heat required to change a substance from a liquid (water) to a gas (steam) or vice versa.

Physical Change

States are usually changed by adjusting temperature.

Latent Heat of Fusion

Latent Heat of Vaporization

Example: CO2

Solid Liquid Gas(not a vapor)

Becomes “dry ice” under very cold conditions

Liquid under pressure at room temperature

Normally gas at room temperature

NOTES:

•Not all substances can exist in all three states.

•Not all substances pass through each state to get to another.

CLASSIFICATION OF MATTER

MATTER

MIXTURE PURESUBSTANCE

Chemical ElementCompound

Measuring Matter

Mass Weight Density Specific Gravity Volume Temperature

MASS

 Mass = The amount of matter in an object .

It is not the same as weight. Is always constant regardless of

location. i.e. Does not depend on the effects of

gravity. Measured with a balance.

Weight

 Weight = Mass(m) x acceleration

due to gravity (g)

Measure of gravitational pull on the body’s mass by the planet or satellite on which it is measured.

Location affects weight. Measured with a scale.

MASS vs. WEIGHT

Earth Moon

Mass 57 kg 57 kg

Weight 125 pounds.

21 pounds

We speak of “weight” as the gravitational pull at the surface of the Earth.

Mount Everest – Further from the Earth’s core results in less weight.

The difference between a balance and a scale.

Question

How can we use the terms mass & weight interchangeably?So long as gravity does not change while we are

doing our measurements, they are interchangeable.EXAMPLE: If two object’s with the same mass are weighed in the same place, their weights will be equal. BUT take one to the moon and it’s weight will decrease but it’s mass will remain the same.

Density

Density = Amount of mass per unit volume (mass / volume)

How tightly packed are the molecules. Most substances contract when cooled

(increase density when molecules move together and become a solid)

Most substances expand when heated (decrease density when molecules move apart and become a liquid or gas)

Units of measure solid or liquid: g/mL or g/L Units of measure for gas: g/L

DENSITY AND THE ATMOSPHERE

OUTER SPACE

Miles Degrees C

Density of air

IONOSPHERE 26-93 -250 - -

300Cannot

be measure

dSTRATOSPHERE 16-25 -10 – (-60) 0.1 g/L

TROPOSPHERE 0-15 25 – (-55) 1.22 g/L

EXAMPLES OF DENSITY

SOLID Gold 19.3 g/mL

Cork0.2 g/mL

LIQUID Mercury 13.6 g/mL(liquid metal)

Water 1 g/mL

GAS Air 1.39 g/L

Hydrogen0.09 g/L

CALCULATING DENSITY

Density = mass/volume

MASS VOLUME

Oak 25 g 5 mL

Poplar 25 g 10 mL

Oak 25 g /5 mL = 5 g/mL

Poplar 25 g/10 mL = 2.5 g/mL

Which is more dense: Oak or Poplar?

Which is more dense: 1 L of pure oxygen or 1 L of pure

nitrogen?

Specific Gravity

Specific Gravity = Comparison of one substances density against a standard such as water (1.0 g/L)

Density of substance (g/mL) Density of water at the same temperature (g/mL)

Allows comparison to a known value. Urine Specific Gravity is used to help

physicians diagnose renal disorders. Normal urine = 1.003 - 1.030 Diabetes mellitus >/= 1.030 due to high glucose

concentrations. Diabetes insipidus </= 1.003 due to large

amounts of water excretion.

VOLUME & TEMPERATURE

Volume = Space occupied by matter measured with a burette,

pipette, cup, spoon…

Temperature = Measurement of molecular activity Determined by a thermometer

ASSIGNMENTS

Continue to work on objectives related to this Lesson.

Read Egan’s chapter 6 Pages 94-95, 96-97, and 100-101

Observe your environment. Look for physical & chemical

properties & changes.