General Chemistry CHM 101 John Tyrell

Dr. John Tyrell Office: Dobo 227 Telephone: 962-7299(campus); 793-3361(home) Email: tyrellj@uncw.edu http://people.uncw.edu/tyrellj/ Office Hours: Mondays 6:30-7:30 p.m & Wednesdays 2:45-3:45 p.m. and by appointment. Drop ins welcome

Grading Policy: Your grade in this course is based on your performance on the following items: Hourly exams (there will be three of them): 50% Final exam: 20% Laboratory work: 15% Quizzes : 15% Labs start next week (not on Monday) (need lab manual & safety goggles)

Keys to Success Come to class Mind as well as body Don’t be bashful Actively do problems. (keep a notebook) It’s like a marathon – keep up a steady pace throughout Cooperation leads to graduation

Let’s get started Chemistry is the study of matter

The Study of Chemistry The Molecular Perspective of Chemistry Matter is the physical material of the universe. Matter is made up of relatively few elements. On the microscopic level, matter consists of atoms and molecules. Atoms combine to form molecules. Molecules may consist of the same type of atoms or different types of atoms.

The Study of Chemistry The Molecular Perspective of Chemistry In these models, we use red to represent oxygen, white to represent hydrogen, and gray to represent carbon.

Classification of Matter States of Matter Matter can be a gas, a liquid, or a solid. These are the three states of matter. Gases have no fixed shape or volume. Gases can be compressed to form liquids. Liquids have no shape, but they do have a volume. Solids are rigid and have a definite shape and volume.

Classification of Matter Pure Substances and Mixtures Atoms consist only of one type of element. Molecules can consist of more than one type of element. Molecules can have only one type of atom (an element). Molecules can have more than one type of atom (a compound). If more than one compound are found together, then the substance is a mixture.

Classification of Matter Pure Substances and Mixtures

Classification of Matter Pure Substances and Mixtures If matter is not uniform throughout, then it is a heterogeneous mixture. If matter is uniform throughout, it is homogeneous. If homogeneous matter can be separated by physical means, then the matter is a mixture. If homogeneous matter cannot be separated by physical means, then the matter is a pure substance. If a pure substance can be decomposed into something else, then the substance is a compound.

Classification of Matter Pure Substances and Mixtures If a pure substance cannot be decomposed into something else, then the substance is an element.

Classification of Matter Compounds Most elements interact to form compounds. The proportions of elements in compounds are the same irrespective of how the compound was formed. Law of Constant Composition (or Law of Definite Proportions): The composition of a pure compound is always the same. Therefore, if water is decomposed, then there will always be twice as much hydrogen gas formed as oxygen gas.