Msharperscience.weebly.com



UNIT 1: MEASUREMENT NOTESScientific NotationA common number used in chemistry is 602,000,000,000,000,000,000,000What is that number in scientific notation? ____________________________________Practice4300________________ 505,000 ____________________ 0.0047 __________________ 2.7 x 103 _______________ 8.8 x 10-4 ___________________ 1.7 x 10-1 ________________Metric Units SI BASE UNITS (METRIC) QUANTITY UNIT SYMBOLLengthMassTemperatureTime REMEMBEREvery measurement requires two parts. 1. __________________________ 2. ______________________Example: 20.0 _____ 1.22 _______Measure to the correct number of _________________________ (significant figures)MEASURINGMeasure to the number of decimal places that you can read on your ruler, balance, or graduated cylinder.Always measure to ________________ more decimal place. This is the ________________or uncertain digit. Significant figures All nonzero numbers are significant. Ex: 276 (3 sig figs) 32,184 (5 sig figs)Zeros between numbers are significant. Ex: 4009 (4 sig figs) 200.05 (5 sig figs)Zeros at the beginning of a number (leading zeros) are NOT significant. Ex: 0.003 (1 sig fig )Zeros at the end of a number without a decimal in the number are NOT significant. Ex: 25,000 (2 sig figs) 900 (1 sig fig)Zeros at the end of a number with a decimal in the number are significant. Ex: 20.0 (3 sig figs) 0.07300 (4 sig figs)Do not include the exponent in numbers in scientific notation. Ex: 6.223 x 108 (4 sig figs)These rules are for measured numbers only. They do not apply to counted numbers such as 24 people or 60 seconds are equal to 1 minute.PRACTICEHow many significant figures are in the following measurements?42.56 g _________ 2) 0.00793 ___________ 3) 8000 __________ 4) 2.70 x 109 ___________USING SIGNIFICANT FIGURES IN CALCULATIONSMultiplication and DivisionYour answer should contain the same number of significant figures as the ____________number of significant figures in the problem.Ex: 45.89 cm x 3.26 cm = ? Calculator = ______________ Answer = ______________ Ex: 45.98 cm2 / 5.7 cm = ? Calculator = ______________ Answer = ______________ Ex: How many significant figures should you have in your answer to the following problem? 3.75 x 21.489 / 2.73 = ________________Addition and subtractionYour answer should contain the same number of _______________ places as the ____________ number of decimal places in the problem.Ex: 18.723 g + 2.11 g = Calculator = ______________ Answer = ______________ Ex: 285.722 g – 58.1 g = Calculator = ______________ Answer = ______________ (HONORS) Ex: 42.675 – 3.91 = ? Subtraction = ______________ 9.8 Round off to correct number of decimal places. Calculator = ______________ Answer = ______________ Metric SystemPREFIXSYMBOLMEANING gigaGbillion (1 x 109) megaMmillion (1 x 106) kilokthousand (1 x 103) hectohhundred (1 x 102) dekadaten (1 x 101) _____________________________________________________ decidtenth (1 x 10-1) centichundredth (1 x 10-2) millimthousandth(1 x 10-3) micromillionth (1 x 10 -6) nanonbillionth (1 x 10-9) Practice1. How many cm are in a meter? ____________________2. Which is larger, a milligram or a microgram? ____________________3. What does the prefix nano mean? ______________________4. What is the symbol for 100? __________________________5. How many grams are in a megagram? ___________________Accuracy and PrecisionAccuracy-Precision –DensityHow do you define density?What is the mathematical formula for density?Units of DensitySolids: ______________ Liquids ______________ Gases: ______________________ Remember: 1 cm3 = ________ The density of water is __________.125 ml of water would have a mass of __________Practice Problems3.50 cm3 of a metal has a mass of 27.51 g. What is the density of the metal? Identify the metal.What is the mass of 12.5 cm3 of magnesium?Calculate the volume of 15.0 g of nickel.Percent ErrorError = difference in the accepted and experimental values% Error = │error│accepted value x 100PracticeAn object has an accepted mass of 45.50 g. In lab a student measured the mass to be 40.00g.What is the error? What is the % error?The accepted density of iron is 7.86 g/cm3. If you measure the density to be 6.99 g/cm3, what is your percent error? ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download