Chapter 2 - Chapter 2 - Basic Chemistry I. Concepts of...

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Chapter 2 - Basic Chemistry I. Concepts of Matter and Energy A. Matter - The “stuff” of the universe. o ** Anything that takes up space and has mass (weight) - Chemistry – studies matter – how it interacts. - Matter exists in solids , liquids , and gases. - Solids – definite shape and volume ex – bones and teeth - Liquids – definite volume, take shape of container ex – blood plasma - Gases – neither definite shape or volume ex – air we breath Physical Change – do not alter the basic nature of a substance ex – Change in state – ice melting Chemical Change – do alter the composition of a substance. - ex – digestion of food by intestines B. Energy – the ability to do work and cause motion. - massless and does not take up space
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- Two Types 1) Kinetic – energy doing work 2) Potential – inactive or stored energy 1) Forms of Energy a. Chemical Energy – stored in the bonds of chemical substances – When bonds are broken, potential energy becomes Kinetic energy. - Human body – all body activities are “run” by the chemical energy from foods we eat. b. Electrical Energy – result from movement of charged particles (ions) - Muscles and nerves depend on ions. c. Mechanical Energy – directly involved in moving matter - ex – muscles moving you legs d. Radiant Energy – energy that travels in wves - ex – x-rays, infrared, light (vision), radio (hearing) and ultraviolet (suntan) waves. 2) Energy Form Conversions - Energy is easily converted from one form to another – electricity into light - Energy conversions are inefficient – this means that some of the energy is
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wasted - ex – muscles – contractions give off heat II. Composition of Matter A. Elements and Atoms o Elements – unique substance – cannot be broken down into simpler substances o ex – Oxygen – O, Carbon – C, Gold – Au, Copper – Cu, Iron – Fe o 112 known elements - ** 90 occur naturally o (4) elements – C, H, O, N – make up 96% of the body. o Periodic Table – Appendix B – pg. 514 – complete listing of the elements o Atoms – building blocks of elements o Designated by 1 or 2 letters – called its atomic symbol o Some atomic symbols – take from the Latin name for the element – Na – sodium – natrium B. Atomic Structure
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o (3) subatomic particles a. protons – (p+) positive charge b. neutrons – (n o ) no charge - protons and neutrons are found in the nucleus c. electrons – (e-) negative charge - orbit the nucleus o ** atoms are electrically neutral – they have a balanced number of protons (+) and electrons (-). o Ex – Hydrogen 1-p+ and 1e- Iron 26 – p+ and 26 – e- 1) Planetary and Orbital Models of an Atom a) Planetary Model – atom compared to a miniature solar system o Protons and Neutrons – found in the nucleus – has a positive charge b) Orbital Model – more modern model o *predicts where electrons are located – found in the electron cloud C. Identifying Elements o * atoms of different elements are composed of different numbers of protons, neutrons and electrons.
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Chapter 2 - Chapter 2 - Basic Chemistry I. Concepts of...

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