Matter:

Matter:

It’s what the world’s made of.

Chemistry Studies Matter- Branches of Chemistry

Organic Study of most carbon-containing compounds Basis for most life processes as well as plastics, drugs,

petrochemicals, food, etc.

Inorganic Study of non-organic substances

Physical Study of properties and changes of matter and their relation to

energy

Analytical- identification of the components and composition of materials

Biochemistry- study of substances and processes occurring in living things

Theoretical- use of math and computers to provide theories that explain chemical observations; predict properties of new compounds

Chemistry Studies Properties Extensive properties

depend on amount of matter present volume, mass, and amount of energy

present Intensive properties

independent of the amount present boiling point, melting point, density,

conducting electricity and energy, phase change energy and others

States of Matter Solid – Definite shape and volume Liquid – Definite volume but variable

shape Assumes the shape of its container

Gas – Neither definite shape or volume Expands to fill any size container Takes the shape of the container

Plasma – Extremely high energy state where electrons have been ejected

Changes of State Melting Freezing Vaporizing

Boiling- change from liquid to vapor within the liquid as well as at the surface

Evaporation- change from liquid to gas at the surface of the liquid; occurs at much lower temperatures than boiling

Condensing Sublimation- example: dry ice (CO2)

Deposition- example: frost forming on a cold surface

What is Matter made of?

ElementsCompoundsMixturesSee classification scheme for matter

on p.11 of the text

What is Matter made of? Elements-cannot be broken down

Atomic-most elements can exist as individual atoms(smallest particle of any element). Examples: Fe, Au, Ag, Al

Molecular-some elements are… Diatomic H2, O2, N2, F2, Cl2, Br2, I2

Triatomic O3

Tetratomic P4

Octatomic S8

Elements are found on Periodic Table

What is Matter made of? Compounds-Two or more elements

chemically bonded together These can be broken down into smaller

compounds or elemental parts Examples: CaCO3(chalk), Fe2O3(rust)

Smallest particle is a Molecule

Pure Substances Always have a fixed composition Can be elements or compounds Always have the same properties Always have the same composition

Pure water is always 11.2% Hydrogen and 88.8% Oxygen by mass

What is Matter made of?

Mixtures-These are made of two or more chemicals that are not chemically bonded together. Examples: Sand, Salt/Pepper, Milk, Blood, Muddy water

Homogeneous – uniform throughout Heterogeneous – differences are found Mixtures can often be separated easily by

physical means such as filtration, distillation or chromatography.

Filtration: Separates solid substances from liquids and solutions.

Coffee FiltersSome water filtersPool filters using

sand or DE- diatomaceous earth (spongy skeleton)

Distillation: SeparatesHomogeneousmixtures using the differences inboiling points.BPH20 = 100˚C

BPNaCl = 808˚C

Water vapor rises first and condenses in the tube.

Chromatography:

Separates substances on the basis of differences in solubility in a solvent.

Classification Flowchart

Physical Properties

Observed without changing the identity of a substance

Volume, mass, size, color, shape, smell, hardness, density, texture, melting & boiling points, temperature…

Physical Changes Change that alters appearance or

form of material but does not change the identity of the substance

Examples: tearing paper, breaking pencil, ice melting

Phase changes are ALWAYS Physical Changes

Chemical Properties What are the chemical activities of

the material Does it react with Oxygen Does it react with Water Does it react with Chlorine Does it react with Fluorine Does it react with …

Chemical Changes A chemical reaction occurs that

produces NEW substances Old chemicals bonds(Reactants) must

be broken and new ones(Products) formed usually with energy exchanging

Example: burning fuel, digesting food, Photosynthesis, rusting iron, plant decay

2 Kinds of Chemical Reactions

Exothermic Releases heat into surroundings Might feel warm or hot to the touch Reactants have higher energy in their bonds Examples:

Mixing acid with bases Burning of a fuel Digestion

2 Kinds of Chemical Reactions

Endothermic Absorbs heat from the surroundings Could feel cool to the touch Products have more energy than reactants Examples:

Cooking an egg Dissolving Baking Soda Photosynthesis Cooking coffee beans

Chemical Equations 2 H2(g) +O2(g) 2 H2O(l) + Energy

Coefficients “yields” (s), (g), (l) Energy is always involved-Heat or Light

Exothermic Endothermic

Balancing will follow later Matter CANNOT be created or destroyed

but it can be changed in reactions

Measuring Matter Using Le Système International (SI)

(Metric System only)(see pg 34) Volume -- V=LxWxH V=r2h

V=4/3r3

Mass -- gram, Kilogram- not affected by gravity, based on quantity of matter

Weight -- Pounds, Ounces- caused by the pull of gravity which can change

Volume – Gallons, Liters- space that a substance takes up

Density = mass/volume

Measurements are wrong! Measurements are not pure

numbers Measurements are made by man

using instruments made by man and subject to error

UNCERTAINTY FACTORS 345±2ml Every measuring device has an UF Usually ½ of the smallest readable

graduation

Uncertainty in Derived Quantities

For Addition and Subtraction Round all numbers to accuracy of the

least Do the desired math operation (A) Add all Uncertainty Factors of each

measurement used above (B) Write as A±B

Uncertainty in Derived Quantities

Multiplication and DivisionA. Round all numbers to accuracy of the least

accurate number involvedB. Do the desired math operation C. Divide each uncertainty by its measurement.

Pick the largest uncertainty from previous stepD. Multiply the Answer (C) times the value of B

B X C = new UF Combine B ± D (Derived answer w/ new UF)

Density:

Physical property of a substance

Mass Density = ----------

Volume

Density Mass/Volume Affects the buoyancy

of material. Does it float?

Is NOT affected by size of sample

Is affected by change in temperature