Unit 5:

Matter and Energy

I. Classification of Matter

P u re S ub s tan ces M ix tu res

M a tte r

Classification of Matter

E le m e n ts C o m p o un ds

P u re S ub s tan ces

A llo ys S o lu tio ns

H o m o ge n eo us

C o llo id s S u spe n sio ns

H e te ro ge n so us

M ix tu res

M a tte r

Pure Substances

A “pure substance” is one that has the same composition throughout

All parts of this substance has the same properties, regardless of shape, size, or state

Examples:

watersilversodium chloridenitrogenheliumsucrose

B.Mixtures

Mixtures are physical combinations of more than one compound and/or element

These are 2 or more distinct substances

May have varying propertiesproperties throughout

Two major categories of mixtures:

1) Heterogeneous

2) Homogeneous

Mixtures

Heterogeneous Mixtures = those that are not the same throughout;

vary in composition; can see the separate

partsExamples: sand &

water, ???

Homogeneous Mixtures =

those that look the same throughout, but can still be separated physically

Examples: 14kt gold, sugar water, ???

C. Properties of Matter

Physical Property

those that can be observed without changing the identity or composition

Ex] density, solubility, phase, etc.

Chemical Property

describes how a substance reacts; composition changes

Ex] flammability, oxidation, etc.

Intensive vs. Extensive Properties

Extensive Properties depend upon the depend upon the amountamount presentMass, shape, volume, etc.

Intensive Properties remain the same remain the same regardlessregardless of amountDensity, boiling point, solubility, etc.

Website reference

http://www.chem1.com/acad/webtext/pre/matter.html

D. Physical and Chemical Changes

Physical changes are generally are reversible

The substance may look differently, but has the same intensive properties

D. Chemical Changes

Chemical changes generally alter the composition of the substance

End product has different properties

Sample is destroyed

II. Particle Diagrams of Matter [drawings of types and phases]

Identify the type of substance and the phase in each diagram below.

Draw a particle diagram of nitrogen gas and iodine.

III. Separation Techniques

These methods separate mixtures that are physically combined

End result, or products, are the compounds or elements that composed the mixture

Four major methods: A) Filtration C) EvaporationB) Distillation D) Chromatography

A. Filtration

Filtration is used to separate a solid from a liquid or a solution; starts with suspension

Materials: filter paper, funnel, collection beaker

Advantages: easy, common, fast, recovers all parts

Disadvantages: inaccurate, difficult with small particles, depends on technique, human error common

B. Distillation

This is a method of separating components of a liquid mixture based on different boiling points

Materials: boiling flask, collection flask, condenser, water, heat source

Advantages: recovers all parts, collects pure substances, separate complex mixtures

Disadvantages: costly equipment, slow, can be difficult

Evaporation is the removal of a solvent by evaporating it, leaving behind the solute

Materials: Evaporating dish, heat sourceAdvantages: easy, common, usually fastDisadvantages: lose solvent, solute may

be contaminated, inaccurate, can be difficult

C. Evaporation

D. Chromatography

This uses solubility rules and mass to separate components of a complex solution

Materials: stationary phase [paper], mobile phase [solution], sample

Advantages: very accurate, rater fast, can separate hundreds of components

Disadvantages: expensive, must have the proper solvent, destroys sample

Several different types: paper, gas, or liquid

IV. Laws of Matter and Energy

A. Law of Conservation of Energy

B. Law of Conservation of Matter

C. Law of Constant Composition

ExceptionException: : nuclear reactions

V. Energy

C h e m ica l N u c le a r

P o ten tia l

H e a t E le c trica l M e cha n ica l T h e rm a l E le c tro m ag n e tic

K in e tic

E n e rgy

B. Changes in Energy

Endothermic

a reaction or change that

ABSORBS

heat energy

Exothermic

a reaction or change that RELEASES

heat energy

C. Temperature vs. Heat

Temperature = the average kinetic energy of the particles within an area

Heat = energy transferred between two objects of different temperatures

Heat moves from hotter object to the colder one

V. Heat Transfer and Calculations

Specific Heat (C)The amount of heat energy lost/gained by a

specific mass of a substance over a certain temperature change

The larger the value of specific heat, the more energy it takes to heat the object, oror the longer time it takes for the object to cool

Specific Heat

substances with LOW specific heats:MetalsAlloysSubstances w/ high

thermal conductivity

substances with LOW specific heats:glassSome PolymerswaterAir, inert gasesSubstances w/ low

thermal conductivity

B. Heat Equation and Calculations

q = m • C • Δ T

q= heat [J or kJ]

C = specific heat [J/gC]Δ T = change in temperature = Tf - Ti