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..

PROPERTIES CHEMICAL PHYSICAL INTENSIVE EXTENSIVE

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 Properties 1. 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 arrangement Based upon energy of particles Based upon distance between particles AKA POTENTIAL AND KINETIC

Solid Gas 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

Solid Gas State or Phase Particle Movement Amount PE Amount KE Example Liquid Gas Vibrate only Very Low Low Ice Vibrate & move past each other Low Medium Water Move freely High High Vapor

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 LIQUID PLASMA SOLID GAS Tightly packed, in a regular pattern Vibrate, 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

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

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: -Boilinga 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 Liquid Melting Solid 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

DE EF -heat Δ PE -heat Δ KE -get farther apart -move faster Gas Boiling DE -heat Δ PE -get farther apart -temp. stay same -boiling EF -heat Δ KE -move faster -temp.  -gas

A C B E D F CD -KE  -slows down -temp.  -Liquid AB -KE  -slows down -temp.  -Gas BC -PE  -closer together -temp. stays same -Condensation

A C B E D F EF -KE  -slows down -temp.  -Solid DE -PE  -closer together -temp. stays same -Freezing

What is the boiling point? What is the melting point? Freezing Point & Freezing Melting Point Melting What is the boiling point? What is the melting point? What is the freezing point?

If melting & freezing points are at the same temp 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 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 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 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

Solutions SOLUTION – 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

H2O H = O = - + + - + - - + - - + - + + - NaCl Na = Cl = + -

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Solutions are Homogeneous Mixtures The solution is well stirred during its formation. The particles will not come out of solution no matter how long it is allowed to stand. The solution is clear and transparent. A solution is considered to be in one phase and will not filter unless extremely fine filter paper is used.

Types of Solutions Gas-Gas Carbon dioxide, Nitrogen, Oxygen (air) Liquid-Gas Water Vapor in Air (moist air) Gas-Liquid Carbon dioxide in Water (soda water) Liquid-Liquid Acetic acid in Water (vinegar) Solid-Liquid Sodium chloride in Water (brine or salt water) 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… 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… Stirring the solution decreasing the particle size of the solute 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

Definitions Solutions can be classified as saturated or unsaturated. A saturated solution contains the maximum quantity of solute that dissolves at that temperature. An unsaturated solution contains less than the maximum amount of solute that can dissolve at a particular temperature

Definitions SUPERSATURATED SOLUTIONS contain more solute than is possible to be dissolved; excess solute will precipitate out of a supersaturated solution, leaving a crystallized solid and a saturated solution. Supersaturated solutions are unstable. The supersaturation is only temporary, and usually accomplished in one of two ways: Warm the solvent so that it will dissolve more, then cool the solution 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.

What are the units for solubility? What is the solubility of NaCl at 600C? What is the change in solubility of NaNO3 from 150C to 600C? How much more KI can be dissolved in 100 grams of water at 300C than KNO3? 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?