CHM 101, 102 Key to success: 1. Do not miss classes 2. Read the textbook ahead of time 3. Complete OWL assignments on time 4. Do problems at the end of each chapter 5. Pay attention in class. Do not carry out a conversation with you classmates during lectures.

I. Chemistry - Study of Matter and Energy Why study chemistry: 1) To understand the nature 2) To bring about a better world Chemistry is also called the Servant Science. Medicine Engineering Space, Planetary Home economics Agriculture, Biology, Defense Computers, TV, CD, VCR, DVD, Cell phones, i-pod, i-Phone, Blackberry, iTune

Communication, Appliances, Automobiles, Instruments (Cat scan, MRI, PET scan) Psychology, Environment, Nutrition, sports, Music, Arts, Magic, etc. 3) Interesting (fun)

Scientific Method

Matter and Energy Matter - Anything that has mass and occupies space. Energy - Does not have mass, but has the ability to do work, to cause physical or chemical changes (light, heat, etc.) Potential energy - stored energy Kinetic energy - motion Changes in Matter and Energy 1) Chemical changes (reactions) - result in the disappearance of old substances and the formation of new ones. A + B C + D 2) Physical changes - do not result in the formation of new substances - melting, evaporation, mixing (energy transfer is occurred).

Chemical change A + B C + D

B. Properties of Matter 1) Chemical properties - the tendency of a substance to undergo or resist certain chemical changes 2) Physical properties – all properties other than chemical: melting point, boiling point, refractive index, odor, color, density, viscosity, etc. C.  Physical States of Matter    Solid    Liquid   Gas

A solid has a definite shape and a definite volume A liquid has no definite shape (it takes the shape of its container) but a definite volume As gas has no definite shape or volume solid liquid gas

Bromine gas solid liquid

D. Classes of Matter

E. Pure substance – same properties everywhere Element – an element cannot be broken down into two or more simpler substances by physical or simple chemical changes Symbols of elements Memorize the first 20

The Periodic Table

Name and Symbols of elements First letter of a chemical symbol is always capitalized and the second is not: Hydrogen Helium The Big Four: Carbon C Hydrogen H Oxygen O Nitrogen N

b) Compound – a substance of definite composition of elements. It can be decomposed into two or more simpler substances by simple chemical changes but not by physical means. Example: water 18 pounds of water contains 16 pounds of O and 2 pounds of H Ratio of O to H by weight = 16 to 2 9 pounds of water contains 8 pounds of O and 1 pounds of H

F. Natural Laws Law of conservation of mass – mass can be neither created nor destroyed in any transformation of matter. 2. Law of conservation of energy – energy can be neither 3. Law of constant composition – a compound consists of elements of definite composition.

Dalton’s Atomic Theory G.   Atoms and Molecules Dalton’s Atomic Theory All matter is composed of very tiny indestructible unit particles called atoms. All atoms of the same element have the same chemical properties. Atoms of different elements have different chemical properties. During chemical reactions, atoms may combine, or combinations of atoms may break down, but the atoms themselves are unchanged. When atoms form compounds (molecules), they unite in small whole number ratios such as 1:1, 1:2, 2:3, etc. A molecule consists of two or more atoms that function as a unit.

a) monatomic elements b) diatomic and polyatomic elements (Homoatomic molecule ) c) Heteroatomic molecule - contains 2 or more kinds of atoms. CO H2O d) Gaseous elements under normal conditions

water H2O

H. Chemical formulas

I. Mixtures

Compounds and mixtures Example: H2O is a compound

Compound vs. Mixture Copyright © Cengage Learning. All rights reserved

Clear Homogeneous mixture - molecules of each component are evenly distributed - one phase Clear Heterogeneous mixture - molecules are unevenly distributed - more than one phase

Concept Check Which of the following is a homogeneous mixture? Pure water Gasoline Jar of jelly beans Soil Copper metal Copyright © Cengage Learning. All rights reserved