Chemistry - Chp 3 - Scientific Measurement - Notes
- 1. Chapter 3 Scientific Measurement
- 2. Section 3.1 Measurements and Their Uncertainty Objectives • Convert measurements to scientific notation • Distinguish among accuracy, precision, and error of a measurement • Determine the number of significant figures in a measurement and in a calculated answer Measurements • We make measurements every day: buying products, sports activities, and cooking • ___________________________ measurements are words, such as heavy or hot • ___________________________ measurements involve numbers (quantities), and depend on: 1.) The reliability of the measuring instrument 2.) The care with which it is read – this is determined by YOU! Scientific Notation • Coefficient raised to the power of _____ (ex. 1.3 x 107) Practice: (numbers greater than ten) • Exponent equals the number of places the original decimal point has been moved to the left to write the number in scientific notation 1.3 x 107 =1.3 x 10 x 10 x 10 x 10 x 10 x 10 x 10 = 13,000,000 3.6 x 104 = Write 240,000 in scientific notation Practice: (numbers less than ten) • The exponent equals the number of places the original decimal point has been moved to the right to write the number in scientific notation 8.1 x 10-3 = 8.1 / 10 x 10 x 10 = 0.0081 7.5 x 10-5 =
- 3. Write .00000000000327 in scientific notation Multiplication and Division • To multiply numbers written in scientific notation, multiply the coefficients and add the exponents. For Example, (3.0 x 104) x (2.0 x 102) = • To divide numbers written in scientific notation, first divide the coefficients. Then subtract the exponent in the denominator (bottom) from the exponent in the numerator (top) 3.0 x 104 = 2.0 x 102 Addition and Subtraction • Before you add or subtract numbers written in scientific notation, you must make the exponents the same • The decimal points must also be aligned before you add or subtract the numbers Add 5.40 x 103 + 6.0 x 102 =
- 4. Name ______________________________ Date ______________________ Per ______ Section Review 3.1 1. a. What is the difference between a qualitative measurement and a quantitative measurement? b. How is a number converted to scientific notation? 2. Classify each statement as either qualitative or quantitative. a. the basketball is orange b. the diameter of the basketball is 31 centimeters c. The air pressure in the basketball is 12 pounds per square inch d. The surface of the basketball has indented seams 3. Write each measurement in scientific notation a. the length of a football field, 91.4 meters b. the diameter of a carbon atom, 0.000000000154 meter c. the radius of Earth, 6378000 meters d. the diameter of a human hair, 0.000008 meter e. the average distance between the center of the sun and the center of Earth, 149600000000 meters 4. Solve each problem, and express each answer in correct scientific notation a. (4 x 107) x (2 x 10-3) b. (6.3 x 10-2) (2.1 x 104) c. (4.6 x 103) – (1.8 x 103) d. (7.1 x 10-2) – (5 x 10-3)