CHEM 1515 1st Edition Exam 1 Study Guide Lecture 1 January 13 Ch 1 1 1 3 Appendix 1 Chemistry is the study of the composition structure properties and changes of matter Matter anything having mass and occupying space Atoms smallest building blocks of matter The properties of matter depend on 1 composition i e the kinds of atoms it contains and 2 structure i e the way the atoms are arranged Although we know of millions of different materials they are only composed of about 100 different kinds of atoms Different atoms come from different elements of which we know of only about 118 Each element has a name and a symbol This symbol always consists of 1 or 2 letters the 1st of which is always capitalized but never the 2nd one For example oxygen O copper Cu sulfur S barium Ba tin Sn iodine I Memorize the 1st 36 elements of the periodic table as well as these Ag silver Au gold Hg mercury Pt platinum Molecule 2 or more atoms attached to each other in a specific way Ch 1 3 A measurement consists of 1 the measured number and 2 the unit System of Units British System used in the U S Metric System used by the rest of the world International System S I a subsystem of the metric system used in the sciences Ba barium Pb lead Sn tin I iodine The advantage of the S I and metric systems is that smaller and larger units differ from one another by powers of 10 Memorize the prefixes for smaller and larger metric S I units from text They can also easily be found online Temperature a measurement taken using a thermometer that indicates how hot or cold an object is Three temperature scales Temp Scale Fahrenheit F Celsius C Kelvin K Water freezes at 32 degrees F 0 degrees C 273 K Water boils at 212 degrees F 100 degrees C 373 K To convert from Kelvin to Celsius C K 273 To convert from Celsius to Kelvin K C 273 To convert from Celsius to Fahrenheit F 1 8 x C 32 To convert from Fahrenheit to Celsius C F 32 1 8 Derived S I Units are obtained by combining basic S I Units Volume the space occupied by an object S I Unit 1 cubic meter 1 m3 264 gallons 1 dm3 1 liter L 1 cm3 1 milliliter mL We typically use cubic centimeters cm3 for solids and milliliters mL for liquids Lecture 2 January 15 Ch 1 3 Appendix 1 Density indicates how heavy or light a substance and is defined as mass per unit volume d m V It is listed in tables for various substances but you must remember that density changes with temperature usually given at 20 degrees C Density is typically used to characterize and identify substances Typical units for density Solids g cm3 Liquids g mL Gases g L Appendix 1 Powers or Exponents of 10 10000 1000 100 10 1 0 1 0 01 0 001 104 103 102 101 100 10 1 10 2 10 3 1 x 104 1 x 103 1 x 102 1 x 101 1 x 100 1 x 10 1 1 x 10 2 1 x 10 3 1 101 1 102 1 103 Exponential Notation Useful for expressing very small or very large numbers indicating the number of significant digits A number is written as a small number times a power of 10 356 0 0036 3 56 3 6 x x 10 3 digit term or coefficient Standard Exponential Notation or Scientific Notation 102 x exponential term 1 digit term 10 Converting to from scientific notation regular number smaller than 1 exponent negative Adding subtracting with scientific notation a Convert to the same power of 10 b Add or subtract the digit terms keep exp term c Facelift if needed Multiplying with scientific notation a Multiply the digit terms b Add the exponents c Facelift if needed Dividing with scientific notation a Divide the digit terms b Subtract the exponents c Facelift if needed Scientific Notation and the Calculator Learn how to enter scientific notation convert to from scientific notation raise to a power extract a root To enter 3 4 x 107 on TI 30Xa Press 3 4 Press EE or exp Press 7 Display 3 4 07 or 3 4 07 meaning 3 4 x 107 To enter 4 2 x 10 5 on TI 30Xa Press 4 2 Press EE or exp Press Press 5 Display 4 2 05 or 4 2 05 meaning 4 2 x 10 5 To convert to scientific notation If display shows 135 Press 2nd Press SCI Display 1 35 02 or 1 35 02 meaning 1 35 x 102 To convert from scientific notation If display shows 1 35 02 meaning 1 35 x 102 Press 2nd Press FLO Display 135 To raise a number to a power 6 2 4 Press 6 2 Press yx Press 4 Press Display 1477 63 5 2 8 To extract a root Press 2 8 Press 2nd Press yx Press 5 Press Warning Display 1 22866 Your calculator may play dirty tricks on you when you least expect it To avoid errors convert a stand alone 10n to 1 x 10n before entering You may wrongly enter 10 x 10n instead of 10n check if a result is displayed in scientific notation A blank space or a minus sign between digits tells you the result is displayed in scientific notation 1 35 02 or 1 35 02 does not mean 1 3502 it means 1 35 x 102 or 135 Lecture 3 January 20 Ch 1 5 1 6 A measurement consists of 1 the measured number and 2 the unit Precision closeness among a set of measured values Accuracy closeness of a measurement to the true value E g an archer who doesn t hit the center of the target but who gets all of his arrows consistently in the same spot has precision On the other hand an archer who only hits the target center once and misses all the rest of his arrows has some accuracy but no precision The archer who gets all of his arrows in the center of the target has both precision AND accuracy Every measurement contains some error In order to minimize these errors we repeat measurements and then report the average We use significant figures to indicate uncertainty in a measured value Significant figures all certain digits plus 1 containing a slight uncertainty How many significant digits are there in a number 1 All non zero digits are significant 2 Zeros between non zero digits are significant 3 Zeros before first non zero digit are not significant 4 Zeros after the last non zero digit are significant if the number contains a decimal point 5 In numbers without a decimal point zeros after the last non zero digit may or may not be significant use scientific notation to avoid ambiguity 6 Numbers obtained by counting Numbers in definitions Conversion factors within the same system are exact numbers and contain …