Matter and Temperature

Chapters: 2,3 and 14

Standards

• SPS2. Students will explore the nature of matter, its classifications, and its system for naming types of matter

• SPS2a. Calculate density when given mass and volume• SPS5. Students will compare and contrast the phases of

matter as they relate to atomic and molecular motion• SPS5a. Compare and contrast the atomic/molecular

motion of solids, liquids, gases and plasmas• SPS5b. Relate temperature, pressure and volume of

gases to the behavior of gases

Classifying Matter

Matter: anything with mass and volume:• Atom: smallest unit of an element• Element: cannot be broken down into

anything simpler (by chemical means) ex hydrogen, oxygen, carbon…

Classifying Matter

• Molecule: two or more different elements chemically bound; smallest unit of a compound

• Compound: made up of molecules -formula ex NaCl

Pure Substances

• Fixed composition and definite properties ex: water, salt, nitrogen, oxygen

Mixtures

• combination of substances: -homogenous: parts are evenly distributed ex vinegar

-heterogeneous: parts are not evenly distributed

ex vegetables in a salad

Mixtures (cont’d)

• Miscible: can mix ex gasoline• Immiscible: cannot mix ex oil and water

Physical Properties of Matter

• Physical Properties: can be observed without changing the identity of the substance ex melting point, boiling point, dissolving magnetism, ability to conduct electricity

Physical Properties (cont’d)

• mass: amount of matter in an object• volume: amount of space an object takes up• density: ratio between mass and volume -D= m/V -measured in g/cm3 or g/mL

mD V

Chemical Properties

• describes how a substance changes into another substance (cannot be reversed)

ex flammability: ability to burn, reactivity: capacity to combine with another

substance, rusting, effervescence (bubbling)

Matter and Energy

Matter- anything that has mass and volume• 4 states: solids, liquids, gases, plasma Energy- ability to do work:• Potential• Kinetic

Kinetic Molecular Theory

Kinetic Molecular Theory (KMT):• All matter is made of constantly moving

particles (atoms, molecules)• All particles have kinetic energy (KE)

Temperature and Kinetic Energy

Temperature• measure of average kinetic energy• the more KE an object has, the higher its

temperatureThermal energy= total KE; depends on:• particle speed- faster particles have more KE • number of particles- more particles have

greater thermal energy

Thermal Energy Quiz

• Which beaker of water has more thermal energy?

B - same temperature, more mass

200 mL

80ºC

A400 mL

80ºC

B

States of Matter

1. solid: definite shape and volume 2. liquid: changes shape but not volume 3. gases: changes shape and volume 4. plasma: no definite shape or volume and

full of moving charged particles

Energy and Solids

Solids• low KE - particles vibrate but can’t move

around• definite shape, volume: *crystalline - repeating geometric pattern *amorphous - no pattern (e.g. glass, wax)

Energy and Liquids

Liquids• higher KE - particles can move, but are still

close together• indefinite shape, not volume• flows-fluid

Energy and GasesGases• high KE – particles move freely• indefinite shape and volume• flows- fluid

Energy and PlasmaPlasma• very high KE- particles collide with enough

energy to ionize (break into charged particles)• lacks definite shape or volume• can conduct electric current (unlike gases)• most common state of matter

Changes of State Releasing Energy

• Condensation- gas to liquid• Freezing- liquid to solid• Temperature is constant during all changes in

state of matter (ex: If energy is added to ice, the temperature

of ice will not rise until all the ice has melted)

Changes of State

• Sublimation Evaporation Condensation

Melting Freezing

• substance does not change during a phase change, but the energy does.

Changes of State Requiring Energy

• Melting Point: temperature at which a substance changes from a solid to a liquid

• Boiling Point: temperature at which a substance changes from a liquid to a gas

Energy Transfer Methods

• Conduction: when objects in direct contact are unequal in temperature

• Convection: occurs in fluids (liquids or gases) -convection currents: rise and fall of fluids due

to temperature differences (plate tectonics, wind)

• Radiation: transfer of energy by EM waves; no physical contact

Energy Transfer

• Heat: thermal energy that flows from a warmer material to a cooler material (energy transfer)

-measured in joules (J)

Heat Transfer

Why does A feel hot and B feel cold?

80ºC

A

10ºC

B

Heat flows from A to your hand = hot. Heat flows from your hand to B = cold.

Energy Transfer

• Conductor: material that can transfer energy easily as heat

ex metals• Insulator: material that cannot transfer

energy easily ex. plastic, foam, wood

Temperature Scales

• T conversions:• Fahrenheit: water boils- 212◦ F water freezes- 32◦F• Celsius: water boils- 100◦ C water freezes- 0◦ C ◦F = 1.8C + 32.0 ◦C = F – 32.0 1.8

Temperature Scales (cont’d)

• Kelvin: based on absolute zero (-273.15 ◦C, when molecular energy is at a minimum)

- theoretically, KE = 0 at absolute zero (but particles actually never stop moving!)

K = ◦C + 273.0 Tκ = Tс + 273

Specific Heat

• Specific Heat (Cp)– amount of energy required to raise the temp. of 1 kg

of material by 1 degree Kelvin– units: J/(kg·K) or J/(kg·°C)

E = cmΔE =energyc = specific heatm = mass

delta T = temp. change

T

Specific Heat Practice

How much energy must be transferred as heatTo 200kg of water in a bathtub to raise thewater’s temperature from 25◦C to 37◦C?Given: Known: Solution:ΔT= 37◦C - 25◦C E = cmΔ T E= 4186J x 200kg x 12K ΔT= 12K kg·Km= 200kg E= 1.0 x 10⁴ kJc= 4186 J

Law of Thermodynamics

• First Law of Thermodynamics: total energy used in any process is conserved

• Second Law of Thermodynamics: energy transferred as heat moves from higher T to a lower T

- energy decreases in all energy transfers - entropy: measure of disorder within a

system when left to itself

Heat Engines

• Heat engines: convert chemical energy to mechanical energy through combustion

- mechanical energy: transferred by work - internal combustion: burns fuel inside

engine; always generate heat

Fluids

• gases, liquids• Exert pressure, bouyancy, • 3 basic principles govern fluids: Archimedes’,

Pascal’s, and Bernoulli’s

Pressure

• Amount of force exerted on a given area

• P = F A• SI unit = Pascal; 1P = 1N/m²• Fluids exert pressure in all directions

area

forcepressure

Buoyant Force

• All fluids exert an upward buoyant force on matter

• Due to increased pressure with increased depth

Archimedes’ Principle

• Archimedes’ principle: buoyant force on an object in fluid is an upward force equal to the weight of the fluid that the object displaces

Buoyancy and Density

• Objects with D = 1.00g/cm³ or less will float

Pascal’s Principle

• Pascal’s principle: if pressure is increased at any point in a container, the pressure increases at all points by the same amount

• P₁ = P₂ or F₁ = F₂ A₁ A₂

Pascal’s Principle Practice

A hydraulic lift lifts a 19,000 N car. If the area ofthe small piston (A₁) equals 10.5 cm² and the area ofthe large piston (A₂) equals 400 cm², what force needsto be exerted on the small piston to lift the car?Given: Known: Solution: F₂ = 19,000N F₁ = F₂ F₁ = (F₂)(A₁) A₁ = 10.5 cm² A₁ A₂ A₂

A₂ = 400 cm² F₁ = (19,000N)(10.5cm²)F ₁ = ? 400cm F₁ = 500N²

Fluids in Motion

• Move faster in smaller areas than large ones (think water through a partially blocked hose)• Viscosity: the resistance of fluids to flow

Bernoulli’s Principle

• Fluid pressure decreases as speed increases

Behavior of Gases

Properties: • Fill container• Mix with each other• Low density• Compressible (unlike solids or liquids, gases are mostly empty

space)

Gas Laws

Describe how the behavior of gas is affected by:• Pressure• Volume• Temperature

(laws help predict the behavior of gases undercertain circumstances)

Boyle’s Law

• Boyle’s Law: volume and pressure of a gas are inversely related

• P₁V₁ = P₂V₂P₁ = initial pressureV₁ = initial volumeP₂ = final volumeV₂ = final volume

P

V

Boyle’s Law Practice

A cylinder has a volume of 7.5 L and contains agas at a pressure of 100 kPa. If the volumechanges to 11 L, what is the final pressure?Given: Known: Solve:P₁ = 100 P P₁V₁ = P₂V₂ P₂ = P₁V₁ V₁ = 7.5 L V₂

V₂ = 11 L P₂ = (100 kPa)(7.5 L) P₂ = ? 11L P₂ = 68 kPa

Gay-Lussac’s Law

• Gay-Lussac’s Law: pressure and temperature are directly related

• P₁ = P₂ T₁ T₂P₁ =initial pressureT₁ = initial tempP₂ = final pressureT₂ = final temp

P

T

Charles’ Law• Charles’ Law: volume and temperature are directly related (at

constant pressure) V₁ = V₂• V₁ = V₂ T₁ T₂

T₁ = initial tempV₁ = initial volumeT₂ = final tempV₂ = final volume

V

T