Chapter 1

The Science of Chemistry

LAB EQUIPMENT

• Instruments are used to extend our ability to observe and make measurements

Beaker

• simple container for stirring, mixing, and heating liquids • usually cylindrical with flat bottom and lip for pouring

Beaker Tongs

• used to carry a beaker after it has been heated

Erlenmeyer Flask

• flat, conical body, cylindrical neck •allows contents to be swirled or stirred during experiment •narrow neck keeps contents from spilling out •also reduces evaporative losses compared to beaker

Volumetric Flask

• flat bottomed bulb with long neck, usually fitted with a stopper • neck has single ring graduation mark • used for making solutions to a specific volume

Graduated Cylinder

• used to accurately measure the volume of a liquid

• more accurate and precise than flasks and beakers

• measurements are to be read from the meniscus

Test Tube/Rack

• finger-like length of glass open at one end, usually with U-shaped bottom

Test Tube Holder

• gripping device used to carry test tube after it’s been heated

Forceps

• handheld instrument used for grasping and holding objects

Dropper w/bulb

• usually glass tubes tapered to a narrow point

• fitted with rubber but at the top

• used to transfer liquids drop by drop

Glass Stirring Rod

• glass rod used to … stir

Retort Stand

• equipment to which clamps can be attached to hold test tubes and other equipment

Separating Funnel

• Funnel-shaped glassware usually with stopper at the top and stopcock at the bottom

• used to separate immiscible liquids

Buret • vertical cylindrical glassware with volumetric graduation and stopcock on the bottom • used to dispense

known amounts of liquid in experiments where precision is necessary

Buret Clamp

• two-sided clamp used to hold a buret to a retort stand

Pipette (w/bulb)

• cylindrical glassware tapered at one end with volumetric graduation marks

• used to transfer precise amounts of liquid

Petri Dish

• shallow glass or plastic lidded dish that biologists used to culture cells

Watch Glass

• circular slightly curved piece of glass

• used to evaporate liquid, hold solids while being weighed or to cover a beaker

Crucible

• container that can withstand high temperatures

Clay Triangle

• used to hold crucible while being heated

Mortar & Pestle

• used to crush, grind, mix solids

• pestle is heavy bat-shaped object

• mortar is a ceramic or stone bowl

MATTER AND ITS PROPERTIES

Section 2

Matter and Its Properties

• Everything is made of matter - anything that has volume and mass • Volume is the amount of three-

dimensional space an object occupies • Mass is a measure of the amount

of matter

Basic Building Blocks of Matter

• The fundamental building blocks of matter are atoms and molecules

• Atom - the smallest unit of an element that maintains the properties of that element

• Element - a pure substance made of only one kind of atom

Compounds

• Compound - a substance that is made from the atoms of two or more elements that are chemically bonded • Many made of molecules - smallest unit

of element or compound that keeps the properties of the element or compound

Properties and Changes in Matter

•A property ! a characteristic that defines an entire group of substances •Can be used to classify an unknown substance as a member of that group

Ex. one large group of elements is the metals Conduct electricity well Therefore, if an unknown element is tested and found to conduct electricity well, it is a metal

Types of Properties

• Extensive properties - depend on the amount of matter that is present – Volume, mass, amount of energy

• Intensive properties - do not depend on the amount of matter present – Melting, boiling, freezing point; density

• Properties also grouped as physical or chemical properties

Physical Properties

•Physical property - a characteristic that can be observed or measured without changing the identity of the substance

•Describe the substance itself, rather than describing how it can change into other substances

•Ex. Melting, boiling, freezing points

Physical Change• A change in a substance that does not

involve a change in the identity of the substance

• When physical change happens, the matter changes state

• Identity of substance doesn’t change

• Ice!water!steam

• H20 ! H20 ! H20• Evaporation

• Melting

• Freezing

• Sublimation

• Dissolving

States of Matter•3 states of matter

•Solid •Liquid •Gas

Solids

•Have fixed volume •Have fixed shape •Atoms held in rigid structure •Atoms only vibrate

Liquids

• Have fixed volume • No fixed shape • Atoms not held together as

strongly as solid • Atoms can “slip” past each

other like marbles • Gives liquid its ability to

flow • Takes shape of container

Gases•No fixed volume •No fixed shape •Atoms weakly attracted •Move fast and randomly •Fill any container

Other States of Matter

•There are other states of matter •Plasma - most of universe made of plasma •Gas whose atoms broken apart and are charged

Chemical Properties and Chemical Changes

• Chemical property relates to a substance’s ability to undergo changes that transform it into different substances

1. Ability of charcoal to burn in air 2. Ability of iron to rust 3.Ability of silver to discolor

Chemical Change• Identities of substances

change and new substances form

Sodium sulfide + cadmium nitrate ! cadmium sulfide + sodium nitrate

ReactantsProducts

•The products are the substances that are formed by the chemical change.

•The reactants are the substances that react in a chemical change.

Carbon plus oxygen yields (or forms)

carbon dioxide.

carbon + oxygen —> carbon dioxide

Evidence of a Chemical Change

Comparison of Physical and Chemical Properties

CLASSIFICATION OF MATTER

Classification of Matter

• All matter can be classified into one of two groups: pure substances or mixtures • A pure substance can be an element or

compound • The makeup of a pure substance is the same

throughout and does not change from sample to sample • Mixtures contain more than one substance • Can vary in composition and properties from

sample to sample and sometimes from one part of a sample to another part of the same sample

Mixtures

• Mixture - a blend of two or more kinds of matter, each of which keeps its own identity and properties • Parts (components) simply mixed

physically • Can usually be separated • Properties of mixtures are a

combination of properties of components

Homogeneous Mixtures

•Homogeneous - uniform (same) in composition •Also called solutions • Ex. Sugar-water, saltwater, etc

Heterogeneous Mixtures

•Heterogeneous - not uniform throughout •Ex. Sand and water

Pure Substances

•Pure substance - has fixed composition and differs from mixture in following ways:

1. Every sample of a given pure substance has exactly the same characteristic properties

2. Every sample of a given pure substance has exactly the same composition

• Pure substances are either elements or compounds •Compounds can be broken down by chemical change –Ex. Breakdown of water

ELEMENTSSection 3

Elemental Names and Symbols

• Elements on periodic table each have their own chemical symbol ! a letter or two that represents that element –H = hydrogen –O = oxygen

• Either 1 or 2 letters resembling English name, or 1 or 2 letters resembling Latin name –Cu = cuprum (copper) –Fe = ferrum (iron)

• Vertical columns of periodic table ! groups (families)

•Horizontal rows of elements ! periods

Types of Elements• Periodic table broadly divided into 2 main sections:

metals and non-metals • Separated by stair-shaped line • Non-metals to right of line • Metals to left of line

Properties of Metals

Metal - element that is a good conductor of heat and electricity

1. At room temperature – most are solids 2. Malleable - can be hammered/rolled into sheets 3. Ductile - can be made into wire 4. High tensile strength - ability to resist breaking

when pulled 5. Usually have silvery or grayish white luster

(shine)

Nonmetals

• Nonmetal - element that is a poor conductor of heat and electricity

• Many are gases at room temperature • Carbon, phosphorous, sulfur are solid – Usually brittle, not malleable/ductile like metals

Chlorine

Bromine

PhosphorousSulfur

Metalloids

• Metalloid - an element that has some characteristics of both metals and nonmetals • Less malleable than metals, not as

brittle as nonmetals

Selenium

SiliconGermanium

Noble Gases

• Elements in group XVIII are noble gases • Generally

unreactive • Neon, argon,

krypton, xenon all used in lighting • Helium used in

party balloons

Neon Argon

Krypton