Presentation on theme: "Scientific Notation Expresses numbers as a multiple of two factors."— Presentation transcript:
1 Chemistry Math – Scientific Notation, Significant Digits and Measurment
2 Scientific Notation Expresses numbers as a multiple of two factors. A number between 1 and 10Ten raised to a power or exponent.Example - 1,750,000,000 = 1.75 x 109Why it’s good! – It makes extremely large numbers and/or small numbers easier to work with.
3 Rules for writing numbers in scientific notation 523,000,000.1. Move the decimal point so the number is between 1 and 10.2. Count the number of places the decimal was moved.3. decimal = +, decimal = -5.23 x 108
4 Practice Convert the following into scientific notation: .000 078 m 1 600 kgcm
5 Rules for converting scientific notation into numbers 2.8 x 10-61. Move the decimal point as many times as the exponent.2. + = decimal , - = decimal
6 Practice Convert the following into numbers. 2.8565 x 104
7 Significant FiguresWhich clock provides the most information?
9 Rules for Recognizing Significant Figures Non-zero numbers are always significant.98.2 g has 32. Zeros between non-zero numbers are always significant.90.2 has 33. All final zeros to the right of the decimal place are significant if they follow a number greater than 0.9.20 g has 34. Zeros that act as placeholders are not significant..0092 g and 920 g have 25. Counting #s and defined quantities have an infinite number of significant figures.1 mile = 5,280 feet
10 Practice ProblemsDetermine the number of significant digits in each measurement.L907.0 kmx 10-4 kgg
11 Rounding Significant Digits An object has a mass of 2.0 g and a volume of 3.00 cm3. What is the density of the object.…The answer should have no more significant digits than the measurement with the fewest significant digits.
12 Rounding RulesIf the digit to the immediate right of the last significant figure is less than five, do not change the last significant figure.2.532 2.53All Significant
13 If the digit to the immediate right of the last significant figure is greater than five, round up the last significant figure.2.536 2.54All Significant
14 If the digit to the immediate right of the last significant figure is equal to five and is followed by a nonzero digit, round up the last significant figure. 2.53All SignificantAll Significant
15 Practice ProblemsRound each number to 5 significant figures. Write your answers in scientific notation.
16 Addition and Subtraction Rules Identify the measurement with the largest increment. Perform the calculation, then round the answer to the measurement with the largest increment.=Answer = 28.4
17 Multiplication and Division Rules Identify the number of significant digits in each number. Perform the calculation, then round the answer to the same number of significant figures as the measurement with the least number of significant figures.Mass = 22.5 grams Volume = 4 mlWhat is the density? g/mlAnswer 6 g/ml
18 Practice Problems a. 52.6 g + 309.1 g + 77.214 g b mL – mLc km x 2.1 kmd m ÷ s
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