1. USS Nautilus is Commissioned (1954)
Homework:
Study for exam
Learn your nomenclature!!!
Nomenclature Worksheet
Key
Reading:
For Monday: Chapter 2 sections 1-4

2. SECTION 2, MWF 10:00AM TO 10:50AM ONLY!!!!!!!
If your last name starts with an A, B, or C, stand up
On Friday, and Friday only, you will NOT come to this room.
GO TO ROOM SQU 316
Everyone else MUST come to this room for the exam.

3. Look at the following. If there is a mistake, fix it
Look at the following. If there is a mistake, fix it. If there is not a mistake, write “correct”
1) Sn(CO3)2 – tin (II) carbonate
4) MnS – manganese sulfide
2) CaS – cadmium sulfide
5) AgH – silver (I) hydride
3) Rb2C2O4 – rubidium oxalate
6) PO4 – phosphate

4. 1) Sn(CO3)2 – tin (II) carbonate
Sn(CO3)2 – tin (IV) carbonate
SnCO3 – tin (II) carbonate
2) CaS – cadmium sulfide
2) CaS – calcium sulfide
CdS – cadmium sulfide
3) Rb2C2O4 – rubidium oxalate
3) correct
4) MnS – manganese sulfide
4) MnS – manganese (II) sulfide
5) AgH – silver (I) hydride
5) AgH – silver (I) hydride
5) AgH – silver hydride
6) PO4 – phosphate
6) PO4 – phosphorous tetroxide
PO4-3 – phosphate

5. Average Atomic Mass
Calculate the average atomic mass of silicon from the following data:
silicon-28 = amu (92.23%)
silicon-29 = amu (4.67%)
silicon-30 = amu (3.10%)

7. Your Calculator Lies to You
What your calculator said:
amu
My periodic table:
28.09 amu
Why?
Significant Figures

8. Significant Figures All about uncertainty
ALL measurements have some uncertainty
between 11½ and 12 cm
about 11.8 cm
about 11¾ cm

9. Sig. Figs. Measured number
Examples
I live 6 and a half miles away
I drink 1.5 liters of water a day
This desk is…
ALWAYS limit these things we call significant figures because uncertainty

10. Sig. Figs.
Exact number:
Examples:
1 foot =
1 kilometer =
1 mile =
24 hours =
4 quarts =
Never limit significant figures because these numbers are DEFINED
The number 1 is usually considered to be exact

11. How many Sig. Figs.? Two rules:
#1) If there IS a decimal point in the number:
Start at right of number and count until the LAST non-zero digit

12. 2 3 . 2 8 1 . 6 8 1 . How many Sig. Figs.? 9 significant figures2 8 1
9 significant figures . 6 8
4 significant figures 1 .
6 significant figures

13. How many Sig. Figs.? Two rules:
#1) If there IS a decimal point in the number:
Start at right of number and count until the LAST non-zero digit
#2) If there is NOT a decimal point in the number
Start at left of number and count until the LAST non-zero digit

14. 7 4 2 9 3 2 3 8 1 How many Sig. Figs.? 5 significant figures8
4 significant figures 1
1 significant figure

15. Significant Practice
0.0005
320000
8900.
0.1528
6 s.f.
7 s.f.
1 s.f.
5 s.f.
2 s.f.
4 s.f.