1. Mrs. Whitaker Unit One, Day One 26 August 2013
Chemistry!!!
Mrs. Whitaker
Unit One, Day One
26 August 2013

2. Around the Room Eye-Wash Stations Safety Shower Student Center
If you’re absent
Objective and Agenda
What to do when you’re done…

3. Remind 101
Awesome technology where I can send you texts/ s with updates
All of our information stays private
If you want to join:
Text to
(leave subject and body blank)

4. Making Measurements
In order to have the most precise answer possible, record as much as you definitely know and then estimate one more digit.
- What does this mean??

5. Measuring Length
What are some units of length??

6. Measuring Length

7. Measuring Length

8. Measuring Length

9. Measuring Volume This is a graduated cylinder
Always measure from the bottom of the meniscus.
Remember to add an estimated digit.

10. Measuring Volume

11. Measuring Volume

12. Measuring Mass This is a triple beam balance.
Mass is measured in grams.
Remember to add an estimated digit!!

14. Significant Figures
All of the digits that can be measured, plus one that is estimated.
Consider the measurement g
--the instrument used to measure was marked to the tenth of a gram (0.1 g) and the digit in the hundredths place was estimated

15. How were these instruments marked?
30,075 mL g
Marked to the ones place
Marked to the tens place
Marked to the thousandths place

16. How many significant figures?
30,075 mL g
3 (2 measured + 1 estimated)
5 ( 4 measured estimated)
6 (5 measured + 1 estimated)

17. How many significant figures?
200
One – zeros have funky rules

18. Rules to determine # of Sig Digs
There are three rules on determining how many significant figures are in a number:
Non-zero digits are always significant.
Any zeros between two significant digits are significant.
A final zero or trailing zeros AFTER THE DECIMAL POINT ONLY are significant.

19. How many significant figures?3 4 2

20. How many significant figures?cm kg m mL 4 2 6 9

21. Individual Practice
Now, work on the first part of the worksheet, on your own.
We haven’t discussed operations yet, so be sure not to work ahead…

22. Multiplication and Division
The answer must be reported with the lowest number of significant figures that are in the problem.

23. Practice 25g / 5cm3 5 g/cm3 0.002cm x 15.2 cm 0.03 cm2 350g / 2.0 cm3
180

24. Addition and Subtraction
The number of decimal places matters!!
Your answer has to be rounded to the lowest number of decimal places.

25. Some Practice =
355 – 23.4 =
17.0 – 2.1 =