Chemistry: A Science for the 21st Century Health and Medicine Sanitation systems; Vaccines and antibiotics Energy and the Environment; Fossil fuels; Solar energy; Nuclear energy Materials and Technology Polymers, ceramics, liquid crystals; Room-temperature superconductors; Molecular computing? Food and Agriculture Genetically modified crops; “Natural” pesticides; Specialized fertilizers 1.1

The Study of Chemistry Macroscopic Microscopic Physical Characteristics of Rust: •a solid •orange color, •forms on the surface of a metal Chemical Characteristics of Rust: •forms on a metal containing iron exposed to air •the chemical formula for Rust is Fe2O3 •there are 3 atoms of oxygen for 2 atoms of iron The purpose of this course is to make you think like a chemist, to look at the macroscopic world, and visualize the particles and event in the microscopic world to explain the large-scale phenomena. 1.2

The scientific method is based on systematic measurement and calculation.

In order to develop an understanding of chemical processes, one must study the properties of pure substances. Pure substances may be obtained by a variety of “separation methods”:

Pure substances have unique and consistent physical and chemical properties. Physical Properties: Melting Temperature Boiling Temperature Color Density

Chemical Property: Ability to chemically react with other pure substances. In a chemical reaction, substances lose their chemical identities and form new substances with new physical and chemical properties.

Composition of Matter Matter is anything that occupies space and has mass. Substance is a form of matter that has a definite composition and distinct properties. Salt dissolved In water Sugar, water Carbon sand In water 1.4

Composition of matters Pure substance- show consistent properties Mixture- they consisted two or more pure substances Homogenous mixture – composition of the mixture is the same throughout. Heterogeneous mixture – composition is not uniform throughout. Compounds– decomposable pure substance by chemical means, contains fixed proportion of the elements Element– substances that can neither be separated chemically into simpler substances nor be created by combing simpler substance

A compound is a substance composed of atoms of two or more elements chemically united in fixed proportions. Compounds can only be separated into their pure components (elements) by chemical means. 1.4 Water (H2O) Glucose (C6H12O6) Ammonia (NH3)

Chemical Compounds in your house!? Bleach - Sodium Hypochlorite (NaClO) Baking Soda - Sodium Bicarbonate (NaHCO3) toothpaste - usually a phosphate group and fluoride Water - H20 Milk- fatty acid and protein group. vinegar- acetic acid bleach- hydrogen peroxide Plant fertiliser such as Baby Bio - Phosphate/nitrogen /Potassium compound Petrol- hydrocarbon!

Physical or Chemical properties of Matter A physical change does not alter the composition or identity of a substance.(freezing, melting, evaporating) A chemical change alters the composition or identity of the substance(s) involved. ice melting sugar dissolving in water hydrogen burns in air to form water 1.6

Memorize these Elements

Group 1A Elements (ns1, n  2) 8.6

Group 2A Elements (ns2, n  2) 8.6

Group 3A Elements (ns2np1, n  2) 8.6

Group 4A Elements (ns2np2, n  2) 8.6

Group 5A Elements (ns2np3, n  2) 8.6

Group 6A Elements (ns2np4, n  2) 8.6

Group 7A Elements (ns2np5, n  2) 8.6