1. Chemistry Basics
Mrs. Mawhiney

2. There are two types of observations:
Quantitative observations involve measurements or estimates that yield meaningful, numerical results.
 Qualitative observations yield descriptive, nonnumerical results. 

3. Comparison of Qualitative and Quantitative Observations
Qualitative (words only)
Quantitative (words and numbers)
The girl has very little money.
The girl has 85 cents.
The man is short.
The man is 5 feet 2 inches tall.
Use a small test tube.
Use a test tube that is 12 centimeters long.
It is a short walk to my house.
It is about 1 mile to my house.
Quantitative and Qualitative Observations Compared

4. How do we measure?
The metric system is an international decimal-based system of measurement.
Because the metric system is a decimal system, making conversions between different units of the metric system are always done with factors of ten.

6. SI Units Measurement Unit Symbol Mass Kilogram kg Length Meter M Time
Second s
Temperature
Kelvin K
Quantity
Mole
mol
Energy
Joule J
Pressure
Pascal Pa

7. Mass and weight What’s the difference?
The mass of an object is a measure of the amount of matter in it.
The basic unit of mass in the International System of Units is the kilogram.
The weight of an object is the force of attraction between the object and the earth (or whatever large, gravity-producing body the object is located on).

8. No Calculator Vomit!!! In Science we use significant figures!
We like accuracy and precision!!

9. Counting Significant Figures
Atlantic / Pacific Method
a. Absent Decimal- Start on “atlantic” side of number & cross out all zeroes until 1st nonzero digit is reached, remaining digits are significant
b. Present decimal- start on the “pacific” side of the number & cross out all zeros until the 1st nonzero digit Is reached, remaining digits are significant

10. How many significant figures are in each of the following measurements?
24 mL
2 significant figures
3001 g
4 significant figures m3
3 significant figures
6.400 x 104 molecules
4 significant figures
560 kg
2 significant figures

11. Density

12. Density Demo
After watching the demonstration, what can you tell me about the reason ice floats in water.
Ice is made up of water right??