Matter and Change

Chapter I

Chemistry

• The study of the composition, structure, and properties of matter and the changes is undergoes.

• Branches of chemistry– Organic chemistry- the study of most carbon-

containing compounds– Inorganic chemistry- the study of all substances

not classified as organic, mainly those compounds that do not contain carbon

Branches of Chemistry

• Physical chemistry-the study of the properties and changes of matter and their relation to energy

• Analytical chemistry- the identification of the components and composition of materials

• Biochemistry- the study of substances and processes occurring in living things

• Theoretical chemistry- the use of mathematics and computers to understand the principles behind observed chemical behavior and to design and predict the properties of new compounds

Chemicals

• Any substance that has a definite composition.– Water – Carbon dioxide– Sucrose (table sugar)– Glucose– Starch– Hydrochloric acid

Research

• Basic research- carried out for the sake of increasing knowledge.– How, when, where….– Teflon discovered by accident

• Applied research- research to solve a problem– New refrigerants that don’t destroy ozone

• Technological development- the production and use of products that improve our quality of life.– Computer, cell phones, etc….– End 1-1

Matter and its properties

• Mass is a measure of the amount of matter in an object

• Matter is anything that takes up space and has mass.

• An atom is the smallest unit of an element• And element is a pure substance made of one kind

of atom.• A compound is a substance is a substance that is

made from the atoms of two or more elements that are chemically bonded.

Properties and changes in matter

• Extensive properties depend on the amount of matter that is present. – concentrations

• Intensive properties do not depend on the amount of matter present. – Salt is salt and is always salt.

Physical properties

• These are the properties that can be observed or measured without changing the identity of the substance.– Color– Hardness– Malleability– Boiling point– Freezing point

Physical change

• A change in a substance that does not involve a change in the identity of the substance– Melting

• Liquid-definite volume but an indefinite shape

– Boiling• Gas- matter that has neither definite volume nor definite

shape• These two are changes of state

– Cutting– Grinding

• Solid- has definite volume and definite shape.

The 4th state

• Plasma– High-temperature physical state of matter in

which atoms lose their electrons• Its in flourescent bulbs.• Lighting• The sun

Chemical properties and changes

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

• A change in which one or more substances are converted into different substances is called a chemical change. – Chemicals that react with each are called reactions– Chemicals that are made are called products

Energy and changes in matter

• Energy must be involved in a chemical or physical change.– Energy can be heat, light or others– Heat is most common in physical change• Melting of ice

– Law of conservation of energy • Energy can not be created or destroyed.

Mixture

• Two or more kinds of matter, each of which retains its own identity and properties.– homogeneous• Uniform in composition

– Also called solutions

– Heterogeneous• Not uniform throughout

Pure Substances

• Has a fixed composition and differs from a mixture in the following ways.– Every sample of a given pure substance has

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

exactly the same composition.

Laboratory Chemicals and Purity

• Laboratory chemicals are considered pure– They do have some impurities– End 1-2

Elements

• The periodic table– Table that the elements are on– Organized by properties– Vertical columns • Groups or families

– Horizontal rows• Periods

Metals

• An element that is a geed conductor of heat and electricity.

• Malleable– Can be flattened

• Ductile– Can be draw into wire

• Has luster– shiney

Non metals

• Poor conductor of heat and electricity• Brittle– Breaks

• Dull– No luster– Not shiny

Metalloid

• Elements that has some characteristics of metals and some characteristics of non-metals.– Silicon for example– Touch the staircase….

• Noble gases– Group 18– Non reactive– Also known as the inert gases

• End of chapter