1. Introduction to Chemistry and Measurement

2. What is Chemistry?
The study of all substances (matter) and the changes they undergo.
EX: Burning Paper (chemical change)
Melting Ice (physical change)

3. Scientific Method
It is a systematic way to answer questions about the natural world.
Steps:
1. observation
2. hypothesis
3.experiment
4. result /conclusion
5. natural law
6. scientific theory

4. Measurement -- major part of science.
Every measurement must include a number or value.
Every measurement needs units.
All sciences use the metric system.

5. International System of Units Table C Ref Table
1. Base Units
- Length is measured in meters (m)
- Mass is measured in grams (g)
- Time is measured in seconds (s)
2.  Some units are derived units
- Area = l x w
- Volume = l x w x h

6. Exceptions to Base Units
- Volume – Liter (L) - Temperature - Celsius degree (⁰C)

7. Metric Prefixes
Used to make units larger or smaller than the base unit. (See Table B)
Prefixes You need to KNOW!
1) mm = 1 m
2) 100 cm = 1 m
3) m = 1 Km

8. Accuracy in Measurements
Precision is achieved when you obtain the same answer over and over
Accuracy is achieved when you obtain a value close to the accepted value. Reasons for uncertain measurements can be that instruments can have flaws or are not calibrated OR human error when estimating

9. Significant Figures -- is all certain digits plus one estimated digit.
Zero – acts as a “place keeper” it tells where the decimal point goes and is NOT significant. If it is after the decimal than it is significant.

10. Scientific Notation
Makes numbers easier to work with, especially really large numbers and decimals.
Ex1)
Ex2)

11. Percent Error
When calculating percent error, we compare the measured value to the accepted value.
Formula from Table T:
Measured Value – Accepted Value X 100
Accepted Value

12. Density Density (found on Table S) is calculated by: Density = mass
volume
Density is expressed in units of gram(g) per mL or cubic centimeter.