Fundamentals of Chemistry

Unit 2 Notes

Matter & Energy

Matter – anything that has mass and takes up space.

Law of Conservation of Mass/Matter

- Matter cannot be created or destroyed in an ordinary chemical

reaction just rearranged to form different substances

Matter can be described using properties..

EXTENSIVE

PHYSICAL

CHEMICAL

INTENSIVE

PROPERTIES

Characteristics of Matter Physical Properties

-Characteristics of a substance that can be observed without the production of a new substance.

Examples:-Color,smell, taste, hardness, density, texture, melting/boiling/freezing points, magnetic attraction, solubility, electrical conductivity, temperature, state or phase

Two types of Physical Properties1. Extensive

-Depends on the particular sample -for example: volume, mass, weight, shape, etc…

2. Intensive-Depends on the type of matter NOT how much there is-For example: color, melting point, specific heat, density, appearance, etc…

Chemical Properties-describes how a substance

reacts or fails to react with other substances to produce new substances.

Examples:-Oxidation, Corrosion,

Hydrolysis,Combustion, Flammability,

Reaction to Acid or Base.

Two Types of Changes

1. Physical Change - an alteration of a substance

that only changes the physical properties of the substance.

*Does not change the chemical composition of the matter!!

2. Chemical Change -an alteration of the chemical

composition of a substance that results in the formation of a new substance

-ALWAYS forms a new substance that has different physical and chemical properties than the original substance. *Also known as a chemical reaction.

Kinetic Theory-All matter is made of tiny particles

in constant motion. Potential Energy (PE)

-energy due to the position or condition

-at the atomic level: the distance between the particles

closer= low PE farther = high PE

Kinetic Energy (KE)-energy due to motion Faster=high KE Slower= low KE

Based upon particle arrangementBased upon energy of particlesBased upon distance between

particlesAKA POTENTIAL AND KINETIC

State or Phase

Particle level picture

Particles description

Keep Volume?

Keep shape?

Solid

Liquid

Gas

Arranged in orderly pattern

Yes Yes

Touching, but not tightly packed

Yes No

Far apart and rarely touching

No No

SOLIDS•Particles are tightly packed, vibrating about a fixed position

•definite shape•definite volume

Heat

LIQUID

Particles are tightly packed, but are far enough apart to slide over one another

indefinite shape a definite volume

Heat

GAS Particles are

very far apart and move freely

indefinite shape indefinite volume

Heat

State or Phase

Particle Movement

Amount PE Amount KE Example

Solid

Liquid

Gas

Very Low

Ice

Low Water

High Vapor

Vibrate only

Vibrate & move past each other

Move freely

Low

Medium

High

Plasma- extraordinary state of matter - consists of high energy

particles- electrons are stripped from

their nuclei-examples: fluorescent lights

stars lightning

*Most Abundant State of Matter in the Universe!*

STATES OF MATTER

SOLID LIQUID GAS PLASMA

Tightly packed, in a regular

patternVibrate, but do not move from place to place

Close together with no regular arrangement.Vibrate, move

about, and slide past each other

Well separated with no regular arrangement.Vibrate and

move freely at high speeds

Has no definite volume or

shape and is composed of

electrical charged particles

ANIMATION

http://www.harcourtschool.com/activity/states_of_matter

/

Phase Changes – Changes of State Adding or removing energy (heat) to a

substance causes phase changes The particles potential energy is changed

(increased or decreased). During a phase change, temperature does

NOT change

Phase changes Melting S Δ L (adding energy) Freezing L Δ S (removing energy)

*Melting point & freezing point of a substance occur at the same temperature.

Phase changes Boiling L Δ G (adding energy) Condensation G Δ L (removing

energy) Evaporation L Δ G (adding energy)

*Difference between boiling & evaporation:

-Boilinga specific temp. below the surface

-Evaporation any temp. at the surface

Phase changes Deposition G Δ S (removing energy)

-Examples: snow

frost

Sublimation S Δ G (adding energy)

-Examples: solid CO2 (dry ice)

solid air fresheners

AB

-heat Δ KE

-move faster

-temp. -solid

BC

-heat Δ PE

-get farther apart

-temp. stay same

-melting

CD

-heat Δ KE

-move faster

-temp. -liquid

Solid

Melting Liqui

d

DE

-heat Δ PE

-get farther apart

-temp. stay same

-boiling

EF

-heat Δ KE

-move faster

-temp.

-gas

Boiling

Gas

A

BC

DE

F

AB

-KE

-slows down

-temp.

-Gas

BC

-PE

-closer together

-temp. stays same

-Condensation

CD

-KE

-slows down

-temp.

-Liquid

A

BC

DE

F

DE

-PE

-closer together

-temp. stays same

-Freezing

EF

-KE

-slows down

-temp.

-Solid

What is the boiling point?

What is the melting point?

What is the freezing point?

Boiling

Boiling Point

MeltingMelting Point

FreezingFreezing Point &

If melting & freezing points are at the same temp. how do you know which?

-depends on whether adding or removing energy

What is this substance?-Water

How do you know?-Boiling & melting & freezing points of water

Matter

Pure Substances Mixtures

Elements Compounds Homogeneous Heterogeneous

Pure Substances-made of only one type of matter

Mixtures-a physical combination of two or

more substances -no particular ratio of particles

Element-made of only one type of atom-cannot be broken down into

simpler substances under normal laboratory conditions

Compound- Atoms of two or more elements, chemically combined in a definite ratio.

Homogeneous Mixtures-two or more substances, physically combined in no definite -The same throughout.-Must be a SOLUTION

Heterogeneous Mixture-two or more substances, physically combined in no definite ratio-Different throughout

Classifications of Mixtures

1. Solutions – Particles are Very tiny, will not separate by filtering, will not settle out when allowed to stand, particles too small to scatter light, (-) Tyndall effect. Ex. Kool Aid, brine

2. Colloids – Particles are tiny, will not separate by filtering, will not settle out when allowed to stand, particles will scatter light, (+) Tyndall effect. Ex. Milk, whipped cream, aerosols

3. Suspension – Particles visible with unaided eye, will separate when filtered, will settle out if allowed to stand, particles will scatter light, (+) Tyndall effect. Ex. Muddy water, snow globe

SolutionsSOLUTION – a solute dissolved in a solvent.

The solvent is the part in greater quantity. For example: In a solution of salt water, salt is the solute and water is the solvent.

ELECTROLYTE - a solution that conducts electricity in water or molten form.

Salt water will conduct electricity.(Electrolyte) Sugar water will not.

Soluble Able to dissolve.

Solute ions (for example: Na+1 and Cl-1) become surrounded by solvent molecules (H2O).

(Opposite charges attract!) “Like dissolves Like”

Polar dissolves Polar

Ex. Salt in Water

Nonpolar dissolves Nonpolar

Ex. Oil in Gasoline

-

-+

+

-+

+

NaCl

Na =

Cl =

+

-

H2O

H =

O =

+

- -

+--+ +

-+-

- + -

+-+

-

+

-+ +

-++

-+

+-

+

+

+

-+

+

CLICK HERE

Solutions are Homogeneous Mixtures

1) The solution is well stirred during its formation.

2) The particles will not come out of solution no matter how long it is allowed to stand.

3) The solution is clear and transparent.4) A solution is considered to be in one

phase and will not filter unless extremely fine filter paper is used.

Types of Solutions1. Gas-Gas Carbon dioxide, Nitrogen,

Oxygen (air)2. Liquid-Gas Water Vapor in Air

(moist air)3. Gas-Liquid Carbon dioxide in Water

(soda water)4. Liquid-Liquid Acetic acid in Water

(vinegar)5. Solid-LiquidSodium chloride in Water

(brine or salt water)6. Solid-Solid Copper in Silver (Sterling Silver)

Solubility

The amount of solute that dissolves in a given quantity of solvent at a given temperature. Usually expressed in grams of solute per 100g

of solvent.

Solution Concentrations

Saturated Solution – Contains the maximum amount of solute for a given amount of solvent at a constant temperature.

Unsaturated Solution - Contains less solute than a saturated solution.

Supersaturated Solution – Contains more solute than is should be able to hold at a given temperature. (Unstable)

Factors that affect solubility… 1) The nature of the solute and solvent.

Some chemicals are just more soluble than others.2) Temperature and pressure.3) The amount of solute already dissolved.

Solubility can be increased by…1) Stirring the solution 2) decreasing the particle size of the solute3) increasing temperature

Solubility Refers to the maximum amount of solute that

will dissolve in a given amount of solvent at a specified temperature and pressure.

g solute / 100 g solvent Saturated vs Unsaturated vs Supersaturated

DefinitionsDefinitionsSolutions can be classified as Solutions can be classified as

saturated or unsaturated.saturated or unsaturated.A saturated solution contains the A saturated solution contains the

maximum quantity of solute that maximum quantity of solute that dissolves at that temperature.dissolves at that temperature.

An unsaturated solution contains An unsaturated solution contains less than the maximum amount of less than the maximum amount of solute that can dissolve at a solute that can dissolve at a particular temperatureparticular temperature

DefinitionsDefinitionsSUPERSATURATED SOLUTIONSSUPERSATURATED SOLUTIONS contain contain

more solute than is possible to be more solute than is possible to be dissolved;dissolved; excess solute will precipitate out of a supersaturated solution, leaving a crystallized solid and a saturated solution.

Supersaturated solutions are unstable. The Supersaturated solutions are unstable. The supersaturation is only temporary, and supersaturation is only temporary, and usually accomplished in one of two ways:usually accomplished in one of two ways:

1.1. Warm the solvent so that it will dissolve Warm the solvent so that it will dissolve more, then cool the solution more, then cool the solution

2. Evaporate some of the solvent carefully so that the solute does not solidify and come out of solution.

ON THE CURVE = SATURATED BELOW CURVE = UNSATURATED ABOVE CURVE = SUPERSATURATED

Note: you may be asked sometimes how much more solute should be used to make something saturated.

1)What are the units for solubility?

2) What is the solubility of NaCl at 600C?

3) What is the change in solubility of NaNO3 from 150C to 600C?

4) How much more KI can be dissolved in 100 grams of water at 300C than KNO3?

5) If 60 grams of NaCl were placed into a beaker with 100 grams of water at 350C and then stirred, what type of solution would result?