Chemistry 3.1Chemistry 3.1

Importance of MeasurementsImportance of Measurements

I. MeasurementsI. Measurements

A. Fundamental in everyday life A. Fundamental in everyday life

1. How many measurements made 1. How many measurements made today?today?

temp, clothes, car speed, amount temp, clothes, car speed, amount of of food, length of shower, grades, etc. food, length of shower, grades, etc.

B. 2 Types of MeasurementsB. 2 Types of Measurements

1. Qualitative1. Qualitative

a. Def - descriptive results in a a. Def - descriptive results in a non-non-numericalnumerical form. form.

b. Ex: brown hat, soft feather, b. Ex: brown hat, soft feather, hard hard ground, thick book.ground, thick book.

2. Quantitative2. Quantitative

a. Def - descriptive results in a a. Def - descriptive results in a numerical numerical form. form.

b. Ex: 5 books, 12:00, 5.8 x 10b. Ex: 5 books, 12:00, 5.8 x 1055, , 45 min.45 min.

II. Scientific NotationII. Scientific Notation

A. Why do we use scientific notation?A. Why do we use scientific notation?

1. Much of chemistry deals with 1. Much of chemistry deals with numbers in scientific notation.numbers in scientific notation.

2. Easy to use.2. Easy to use.

3. Saves time.3. Saves time.

B. Def – a number written as two B. Def – a number written as two separate numbers. separate numbers. 4.5 x 10 4.5 x 1022

C. Two PartsC. Two Parts1. Coefficient – 11. Coefficient – 1stst part of sci. notation part of sci. notation

between 1 and 10between 1 and 10-Ex: 4.55, 6.58, 1.20002-Ex: 4.55, 6.58, 1.20002

2. Exponent – 22. Exponent – 2ndnd part of sci. notation part of sci. notation begins with “10” + raised to begins with “10” + raised to

the power of another number.the power of another number.-Ex 10-Ex 101212, 10, 1088, 10, 1022..

negative exponent = # smaller than negative exponent = # smaller than 11

positive exponent = # larger than 1positive exponent = # larger than 1

Put into Scientific notation:Put into Scientific notation:

a. 602,200,000,000,000a. 602,200,000,000,000

b. .00000000000000000000005b. .00000000000000000000005

c. 8.25 x 16c. 8.25 x 16

6.022 x 1014

5.0 x 10-23

1.32 x 102

D. MultiplicationD. Multiplication

1. Multiply coefficients1. Multiply coefficients

2. Add exponents2. Add exponents

E. DivisionE. Division

1. Divide coefficients1. Divide coefficients

2. Subtract exponents2. Subtract exponents

F. AddingF. Adding1. Make exponents the same number1. Make exponents the same number2. Add coefficients2. Add coefficients3. Keep exponents the same3. Keep exponents the same

G. SubtractingG. Subtracting1. Make exponents the same number1. Make exponents the same number2. Subtract coefficients2. Subtract coefficients3. Keep exponents the same3. Keep exponents the same

In Class ProblemsIn Class Problems

1. (4.0 x 101. (4.0 x 1055) x (3.5 x10) x (3.5 x1033) )

2. (6.7 x 102. (6.7 x 1033) + (3.2 x 10) + (3.2 x 1011) )

3. (4.45 x 103. (4.45 x 1033) / (2.25 x 10) / (2.25 x 1088) )

4. (1.25 x 104. (1.25 x 1033) - (6.7 x 10) - (6.7 x 10-3-3) )

5. 5. (8.2 x 10(8.2 x 1055) + (2.9 x 10) + (2.9 x 1022))

(6.7 x 10(6.7 x 1033) - (4.3 x 10) - (4.3 x 10-2-2) )