Transcript Scientific Notation/Sig Fig Notes

Significant Figure Notes
With scientific notation too
Sig Figs
• Rule 1: “Non-Zeroes Count”
NON-ZERO numbers ARE significant
How many sig figs?
3.1428 ____
3.14 ____ 469 ____
Sig Figs
• Rule 2: “Sandwiched Zeroes Count”
All zeros BETWEEN significant digits ARE
significant.
How many sig figs?
7.053 x 103 ____
70501 ____ 3020 ____
Only count the numbers to the left
of the multiplication sign!
Sig Figs
• Rule 3: “Lefty Zeroes Don’t Count”
Zeroes to the LEFT of significant figures are
NOT significant.
How many sig figs?
0.0056 ____
0.07089 ____ 0.000001 ____
Sig Figs
• Rule 4: “Righty Zeroes…Sometimes Count”
• Zeroes on the far right ARE significant if the
number contains a DECIMAL POINT
• Zeroes on the far right are NOT significant if the
number has NO decimal point
How many sig figs?
4.300 x 10-4 ____
200 ____
0.010050 ____
78020 ____
Practice
We Do:
Next, try the “You Do”
problems on your
3.705 mL _____
own!!
0.0052 g _____
82,000 s _____
1
6.19 x 10 years ______
Scientific Notation
I Do: 3250000000 
0.00034

Scientific Notation
I Do: 3250000000 
0.00034

We Do: 0.025

55, 000 
Now try the “You Do” problems on your own!
Scientific Notation IN REVERSE!
Make sure you know how to go in both directions!
4.78 x 10-2 
5.50 x 104 
This can also be done with a calculator!
Addition/Subtraction
When you add or subtract numbers with
different precision, you must round your final
answer to the least precise number place.
Ex.
150.0
g
+ 0.507 g
150.507  150.5 g
Addition/Subtraction
When you add or subtract numbers with
different precision, you must round your final
answer to the least precise number place.
We Do: What is the
total mass of 33.0 g of
KCl and 56.50 g of
H 2 O 2?
Now try the “You Do!”
Multiplication/Division
When you multiply or divide numbers with
different precision, you must round your final
answer to the least number of sig figs.
We Do: What is the
density (D = m/V) of a
87.45 g metal sample
with a volume of 2.0 cm3?
Now try the “You Do!”