CHEM 1102 ASPECTS OF CHEMISTRY Dr. BILIN PAULA TSAI Dr. SANGEETA MEREDDY

CHEMISTRY THE CENTRAL SCIENCE –Explains all aspects of daily life A QUALITATIVE SCIENCE –Make and record observations A QUANTITATIVE SCIENCE –How much, how many?

CHEMISTRY AN EXPERIMENTAL SCIENCE –Observe and test; laboratory requirement INTELLECTUAL PURSUIT –Scientific method (observe, hypothesize, test, theorize, predict, retest and refine, develop law) METHOD OF INQUIRY –To probe the world around us and to enable advances in our quality of life

CHEMISTRY APPLIED TO ALL ASPECTS OF LIFE Health care including diagnostics (MRI, CAT, X- rays), medicine (pharmaceuticals) and prevention (cholesterol, heart, osteoporosis) Materials for buildings, clothing, roads, consumer products (nylon, kevlar, composites) Transportation fuel (ethanol-gas blends) Agriculture and food (fertilizers, pesticides, additives, sugar substitutes) Communication, electronics and computers

CHEMISTRY Study of Matter –Matter is characterized by mass and volume –Matter has physical and chemical properties –There are three states of matter: Gas, Liquid, Solid Study of how matter changes Figure 1.8 shows how matter is classified.

MIXTURE A mixture consists of one or more substances present in no fixed proportion. Can be separated into substances by physical means; purification. Homogeneous mixtures or solutions have uniform properties throughout –Solution of water and sugar, air we breathe Heterogeneous mixtures or solutions have nonuniform properties throughout –Oil and vinegar, concrete, colloids (T 1.2)

PURE SUBSTANCE In chemistry, a pure substance has characteristic physical and chemical (phys/chem) properties. Cannot be broken down by physical means. Pure substances are elements or compounds.

ELEMENT Fundamental type of matter that cannot be chemically broken down. There are 116 known elements with 90 occurring naturally; shown on the Periodic Table Building blocks for all substances. Classified as metals (75%), nonmetals (20%) or metalloids (5%). Elements have characteristic phys/chem properties

COMPOUND A chemical substance made up of two or more elements in fixed ratio. More than 20 million compounds are known. Compounds have characteristic phys/chem properties. Cannot be resolved into its constituent elements via physical means.

PHYSICAL PROPERTIES Characteristics of a substance that do not result in a change in the identity of the substance –Examples: color, boiling point, freezing point, solubility, density, hardness, conductivity, odor Physical changes (Chapter 2) –Change in form of matter without changing its chemical identity. E.g. boiling is a change from liquid to vapor

CHEMICAL PROPERTIES Characteristics of a substance that result in a change in the identity of the substance –Examples: Reactivity; tendency to burn in oxygen, explode; behave as an acid or base, corrode, decompose Chemical changes (Chemical Reactions; Chapter 2) –Rearrangement of atoms to give new chemical species