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 4 th 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