Chemistry 3.1 Importance of Measurements

I. Measurements A. Fundamental in everyday life 1. How many measurements made today? temp, clothes, car speed, amount of food, length of shower, grades, etc. B. 2 Types of Measurements 1. Qualitative a. Def - descriptive results in a non- numerical form.

b. Ex: brown hat, soft feather, hard ground, thick book. 2. Quantitative a. Def - descriptive results in a numerical form. b. Ex: 5 books, 12:00, 5.8 x 10 5, 45 min.

II. Scientific Notation A. Why do we use scientific notation? 1. Much of chemistry deals with numbers in scientific notation. 2. Easy to use. 3. Saves time. B. Def – a number written as two separate numbers.  4.5 x 10 2

C. Two Parts 1. Coefficient – 1 st part of sci. notation  between 1 and 10 -Ex: 4.55, 6.58, Exponent – 2 nd part of sci. notation  begins with “10” + raised to the power of another number. -Ex 10 12, 10 8, 10 2.

 negative exponent = # smaller than 1  positive exponent = # larger than 1 Put into Scientific notation: a. 602,200,000,000,000 b c x x x x 10 2

D. Multiplication 1. Multiply coefficients 2. Add exponents E. Division 1. Divide coefficients 2. Subtract exponents

F. Adding 1. Make exponents the same number 2. Add coefficients 3. Keep exponents the same G. Subtracting 1. Make exponents the same number 2. Subtract coefficients 3. Keep exponents the same

In Class Problems 1. (4.0 x 10 5 ) x (3.5 x10 3 ) 2. (6.7 x 10 3 ) + (3.2 x 10 1 ) 3. (4.45 x 10 3 ) / (2.25 x 10 8 ) 4. (1.25 x 10 3 ) - (6.7 x ) 5. (8.2 x 10 5 ) + (2.9 x 10 2 ) (6.7 x 10 3 ) - (4.3 x ) (6.7 x 10 3 ) - (4.3 x )