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Chemistry - Conversion Notes I. Chemistry A. The study of the structure and properties of matter. B. Five areas of chemistry. 1) Organic chemistry 2) Inorganic chemistry 3) Biochemistry 4) Analytical chemistry 5) Physical chemistry C. Technology – Means by which society provides its members with those things needed and desired. D. Macroscopic vs. microscopic. E. Chemical Property - Characteristics that can not be observed without altering the substance (burning, reactions with acids). F. Physical Property - Characteristics that can be observed without altering the identity of a substance (density, color, melting point). G. Chemical Change - The production of new substances with different properties. II. Matter A. Anything that takes up space and has mass. B. Extensive (quantitative) properties vs. intensive (qualitative) properties. C. Phases of matter. 1. The phases of matter are due to differences in the relationship between the particles that make up the substance. 2. Solid - The atoms or molecules are tightly packed together. Solids have a definite shape and volume. 3. Liquid - The particles are slightly separated and can move over one another. They have a definite volume but no definite shape. 4. Gas - The atoms or molecules are widely separated with no interactions between them. No definite shape or volume. 5. Plasma - Very high energy state, the electrons are stripped away from the nucleus, the sun is an example D. Weight - The measure of the force of gravity on an object. Weight changes, increases as you get closer to sea level, decreases as you get higher. Measured with a scale. E. Mass - The amount of matter in an object. Mass never changes. Mass is measured on a balance. F. Mixture – Two or more substances together but not electrically attracted (bonded). 1) Homogeneous 2) Heterogeneous III. Energy A. The capacity to do work. B. Types 1. Potential - The energy of position (car on a hill). 2. Kinetic - The energy of motion (car rolling down a hill). IV. The Scientific Method A. A logical approach to solving problems. B. Alchemy – Quest to turn cheaper metals into gold. B. Steps 1. Define the problem -What do you want to solve? 2. Make observations or collect data - Find out all you can about your problem. 3. Form a hypothesis - A possible solution to your problem. 4. Experiment - Test your hypothesis. 5. Conclusions - Was your hypothesis correct? C. Scientific Law - Describes something ( Law of Conservation of Matter). D. Scientific Theory - Theories are backed by facts, they explain something The Theory of Relativity explains how atomic bombs work. * Reading - Prentice Hall Chemistry pages 7 thru 25, and 39 thru 47. I. The International System (SI System) A. Based on ten. B. Used by most countries and scientists around the world. C. Easy to convert measurements. D. Prefixs are standard, they are used with each base unit. 1. Micro - One millionth (.000001) 2. Milli - One thousandth (.001) 3. Centi - One hundredth (.01) 4. Deci - One tenth (.1) 5. Kilo - One thousand times (1000) E. Base Units 1. Meter - Length 2. Gram - Mass 3. Liter - Volume 4. Joule - Energy F. Conversion __________________________________________________________________ Kilo Hecto Deca Base Deci Centi Milli 1 gram equals ____________ milligrams 10 centimeters equals ______________ millimeters 15 decameters equals ______________ kilometers 235 kilometers equals ______________ millimeters II. Significant Figures A. Indicate the accuracy of a calculation. B. Accuracy – Measures how close a measurement comes to the true value of what is being measured. C. Precision – Measures how close a series of measurements of an object are to one another. D. The greater the number of sig figs, the more accurate your calculation can be. E. Rules 1. Digits other than zero are always significant. 2. Final zeros after a decimal are significant (23.30). 3. Zeros between significant digits are counted (706). 4. Zeros used to space decimal points are not significant (200, .007). 5. Conversion factors do not limit the number of sig figs in the answer, only the least number of sig figs in the measurements. F. The answer to a calculation (multiplication, division) can have no more sig figs than the least accurate number used in the problem. 2.345 X 5.2 = 12 III. Temperature A. Measures the kinetic energy (movement of particles) of an object. B. There is a lower temperature limit (absolute zero -273 C) but no upper limit. C. Several different temperature scales, we use Celsius and Kelvin in science. D. Kelvin = Celsius temperature plus 273. IV. Scientific Notation A. Used by scientists because it makes working with very large and small numbers easier. B. Significant figures are written in a form so they are between 1 and 9.99999, the placeholders are shown as a power of ten. When you move the decimal to the right (numbers less than 1) you have a negative power of ten. 2300 = 2.3 X 103 .000456 = 4.56 X 10-4 C. To get exponents on your calculator, use the EXP or EE button. D. Multiplication in Scientific Notation Example 2.0 X 10-6 * 3.0 X 10-3 1. Multiply the significant figures together. 2.0 X 3.0 = 6.0 2. Add the exponents together. -6 + -3 = -9 2.0 X 10-6 * 3.0 X 10-3 = 6.0 X 10-9 E. Division in Scientific Notation Example 5.0 X 104 / 2.0 X 102 1. Divide the sig figs. 5.0 / 2.0 = 2.5 2. Subtract the exponents. 4-2=2 5.0 X 104 / 2.0 X 102 = 2.5 X 102 F. To add or subtract in scientific notation you just add or subtract the significant figures as long as the exponents are the same. 4.0 X 107 + 3.0 X 107 = 7.0 X 107 IV. Density A. Mass divided by volume. B. Constant, each substance has a density that does not change, can be used for identification. C. Water has a density of 1.0 gram/ milliliter, substances with densities higher than 1.0 g./ml. will sink, densities lower than 1.0 g./ml. will float. D. Calculation A piece of plastic with a volume of 2.0 ml. has a mass of 6.0 grams. What is the density of the object? D = M/V D = 6.0 g. / 2.0 ml. = 3.0 g. / ml. E. Rearranging Formulas A piece of plastic has a mass of 8.0 g. and a density of 4.5 g. / ml.. What is the volume of the plastic? D = M/V V = M/D V = 8.0 g. / 4.5 g. / ml. V = 1.8 ml. A wooden block has a density of .85 g. / ml. and a volume 12 cm 3. . What is the mass of the block? D =M/V M=DXV M = .85 g. / ml. X 12 cm3. M = 10 grams V. Factor Labeling Conversions A. Used to convert from one unit to another. B. The units tell us whether to divide or multiply. C. Examples 45 pounds = ____________ grams 454 grams = 1.00 pounds 45 pounds x 454 grams = 2.0 x 104 grams 1 pound 14.5 pints = _________ gallons 2.00 pints = 1.00 quarts 4.00 quarts = 1.00 gallons 14.5 pints x 1.00 qts. x 1.00 gallons = 1.81 gallons 2.00 pts. 4.00 qts. 1.54 mile = _______ feet hour second 5280 ft. = 1.00 mile 3600 sec = 1.00 hour 1.54 mi. x 5280 ft. x 1.00 hr. = 2.26 ft. hr. 1.00 mi. 3600 sec sec 25 grams = ________ pound milliliter quart 454 grams = 1.00 pound 1.00 quart = 1.06 liter 1000.0 ml. = 1.00 liter 25 gram x 1.00 lb. x 1000.0 ml. x 1.06 lit. = 58 lb. ml. 454 gr. 1.00 lit. 1.00 qt. qt. * Read in Prentice Hall Chemistry pages 63 thru 92.