CHEM 101 1st EditionLecture 3Outline of Last Lecture I. An introduction to Mixtures, the Periodic Table of Elements and the Metric SystemOutline of Current Lecture II. Significant FiguresIII.Scientific NotationIV. EstimatesV. Accuracy and PrecisionCurrent LectureII. Significant Figures: each of the digits of a number that are used to express it to the required degree of accuracy, starting from the first nonzero digit. We will abbreviate this as (sig figs) in this class.Significant figures are critical when reporting scientific data because they give the reader an idea of how well you could actually measure/report your data. Before looking at a few examples, let's summarize the rules for significant figures.1. ALL non-zero numbers (1, 2, 3, 4, 5, 6, 7, 8, 9) are ALWAYS significant figures.2. ALL zeroes between non-zero numbers are ALWAYS significant.3. ALL zeroes at the end of a number containing a decimal point are ALWAYS significant figures.4. Zeros at the beginning of a number containing a decimal are NOT significant figures. 5. Zeros at the end of a number not containing a decimal are generally ambiguous. b. How then do you write the number 100 to indicate the correct number of significant figures? By using Scientific Notation!These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.III. Scientific Notation: (also referred to as "standard form" or "standard index form") is a way of writing numbers that are too big or too small to be conveniently written in decimal form.a. Example: 100 contains at least 1 significant figure but could contain up to 3 sig figs, depending on whether the estimate is in the 10’s place or the 1’s.100 written w/ 1 sig fig is: 1 x 10²100 written w/ 2 sig figs: 1.0 x 10²100 written w/ 3 sig figs: 1.00 x 10²b. What you do here is count the number of places that the decimal point would have to move to get one nonzero digit to the left of the decimal.c. This number is used as your exponent.i. If the decimal moves to the right the exponent is negativeii. If the decimal moves to the left the exponent is positiveEx: 1231 = 1.231 x 10¯³IV. Mathematical Operations of Significant Figures:a. Addition & Subtraction: the answer can only have as many decimal places as the number with the fewest digits after the decimal point.b. Multiplication & Division: the answer can only have as many sig figs as the number with the fewest sig figs. Often times writing a number with the correct number of sig figs will require you to round up or down. V. Rules of Rounding:a. If the number being dropped is greater than 5, increase the last saved digit by 1b. If the number being dropped is less than 5, leave the last digit.c. If the number being dropped is exactly 5, there is no standard procedure for this but in this class we will round up. d. If a problem includes multiple steps NEVERround the numbers until the calculation is complete. Only round your final answer.VI. Estimates: when taking scientific measurements it is important to intentionally include a number (likely a decimal) as an estimate. This means the measurement may contain an error which makes your measurements more accurate. a. When measuring a liquid in a buret the solution will form a concave shape- this isknown as a meniscus. You read the measurement from the lowest point. VII. Accuracy and Precisiona. How close the experimental results were to the true or real value for the quantitybeing measured is known as accuracy. b. Precision: refers to how reproducible a measurement is if the same sample is measured several times. The more significant figures, the more precise the measurement. c. Density is a physical property that can be extremely useful in identifying an object. Density is the ratio of the mass of an object and its volume.i. D = M/Vii. An object with a density less than 1.00 g/mL will