SURVEY OF CHEMISTRY I

CHEM 1151

CHAPTER 1

DR. AUGUSTINE OFORI AGYEMANAssistant professor of chemistryDepartment of natural sciences

Clayton state university

CHAPTER 1

MATTER

CHEMISTRY AND MATTER

Chemistry - Is the study of matter and energy and the interactions between them

- Involves studying the properties and behavior of matter

Matter - Anything that has mass and occupies space

Examples

- Living and nonliving things - Things that can be seen: animals, plants, soil, water, clothes, books

- Things that cannot be seen: air, bacteria

CHEMISTRY AND MATTER

Energy - The ability to do work

- Forms of energy (sound, heat, light) are NOT considered to be matter

Mass- Amount of matter in an object

Volume- The amount of space that the matter takes up

CHEMISTRY AND MATTER

Difference between Mass and Weight

Mass - is a measure of total quantity of matter in an object

- constant and independent of location- instrument: the mass balance

Weight - is a measure of the force exerted on an object by gravitational force

- weight = mass x gravitational force- changes with location

(e.g. gravitational attraction on the moon is 1/6th that on the earth)- instrument: spring scale

PHYSICAL STATES OF MATTER

Three physical states of matter: solid, liquid, and gas

Solid - Has a definite shape and a definite volume

Examplesice, book, table, TV set

PHYSICAL STATES OF MATTER

Three physical states of matter: solid, liquid, and gas

Liquid - Has an indefinite shape and a definite volume

- Always takes the shape of its container (the portion it occupies)

Examplesdrinking water, juice

PHYSICAL STATES OF MATTER

Three physical states of matter: solid, liquid, and gas

Gas - Has an indefinite shape and an indefinite volume

- Always completely fills its container, taking the shape and volume of the container

Examplesair, water vapor (steam)

PHYSICAL STATES OF MATTER

State of matter depends on:- Temperature

- Surrounding pressure- Strength of forces holding the structural particles together

- Water can be found in all three physical states:solid ice, liquid water, and gaseous steam.

PROPERTIES OF MATTER

Two categories: physical and chemical properties

Physical Property - Does not change the identity or composition of a substance

- Does not involve changing a substance into another

Examplesshape, color, odor, density, taste, feel, mass, volume

phase, melting point, boiling point, hardness

PROPERTIES OF MATTER

Two categories: physical and chemical properties

Chemical Property - Involves changing a substance into another substance

(chemical reactions) - Describes the reactivity of a material

Examplesheat of combustion, flammability, enthalpy of formation,

explosiveness, toxicity, ionization potential, electronegativity

PROPERTIES OF MATTER

Two categories: physical and chemical properties

Chemical Property - Failure to undergo a chemical change is also considered

a chemical property

Examples- inability of glass to burn

- gold not reacting with water

Two categories of changes in matter: physical and chemical changes

Physical Change - When a substance changes its physical appearance

but not its chemical composition

Examples- change of state (from liquid to gas, from liquid to solid, etc.)

- when liquid water evaporates to steam or freezes to ice

PROPERTIES OF MATTER

Two categories of changes in matter: physical and chemical changes

Chemical Change - When a substance undergoes a change in chemical composition

- Undergoes a chemical reaction- Converts into one or more new substances

Examples- rusting of iron exposed to moist air

- combustion of methane - burning of hydrogen in air

PROPERTIES OF MATTER

PROPERTIES OF MATTERProperties can also be divided into extensive and intensive

Extensive Property - Depends on the amount of sample under investigation

Examplesmass, volume

Intensive Property - Does not depend on the quantity of sample

- Determines the identity of the sample

Examplesmelting point, boiling point, density

CHEMICAL COMPOSITION

SubstanceA material that is chemically the same throughout

Pure Substance - Matter that has distinct properties and definite composition

- Cannot be separated into other kinds of matter by any physical means

Examplespure water, pure salt

Elements - Pure substances that cannot be reduced to simpler

substances by normal chemical means- Fundamental building blocks of all matter

Examplessilver, carbon, sodium, oxygen, hydrogen

- Note that O2, N2, S8, are elements

CHEMICAL COMPOSITION

Elements - 117 elements are known at present

- 92 are naturally occurring and 25 are synthesized in the laboratory

- Only 5 elements account for over 90% of Earth’s crust(oxygen, silicon, aluminum, iron, and calcium)

- Only 3 elements account for over 90% of the human body mass(oxygen, carbon, hydrogen)

CHEMICAL COMPOSITION

Elements The symbol for each element consists of one or two letters derived

from the element’s name, with the first letter capitalized

Some elements and their symbols

Carbon CAluminum AlBarium BaBeryllium BeCopper CuFlourine FIron FeGallium Ga

Germanium GeHydrogen HHelium HeMercury HgIodine ILithium LiMagnesium MgManganese Mn

Nitrogen NSodium NaNickel NiOxygen OPhosphorus PLead PbPlatinum PtSulfur S

CHEMICAL COMPOSITION

Compounds - Pure substances that can be broken into two or

more simpler pure substances by chemical means

- Combination of two or more elements

ExamplesWater (H2O), carbon dioxide (CO2), sodium chloride (NaCl)

CHEMICAL COMPOSITION

CHEMICAL COMPOSITION

Mixture - A combination of two or more pure substances

Examples grains of rice and wheat

cereal and sugarsalt and sand

- Components of a mixture can be separated by physical means (filtration, distillation, the use of magnet for metals)

CLASSIFICATION OF MIXTURES

Homogeneous Mixture (Solution) - Is uniform throughout

- Contains only one visibly distinct phase

Examples- sugar or salt dissolved in water

- glass- alloys

(copper & tin → Bronze) (iron, carbon, chromium, and other substances → stainless steel)

- air (homogeneous mixture of nitrogen, oxygen, and other substances)

CLASSIFICATION OF MIXTURES

Heterogeneous Mixture - Does not have the same composition

- Contains visibly different phases

Examplesrocks, wood, soils

- Physical combination of substances produces a mixture

- Chemical combination of substances produces a compound

MATTER

PURESUBSTANCE MIXTURE

ELEMENT COMPOUND HOMOGENEOUSMIXTURE

HETEROGENEOUSMIXTURE

CLASSES OF MATTER