Scientific Notation, Sigs Figs, and Dimensional Analysis

For Class on 9/4/13
Scribe Post Author: Ashley M.


Yesterday in class we reviewed the homework sheets assigned on 9/3, practiced dimensional analysis, and prepared for the quiz tomorrow, Friday Sept. 6.  The answers to the homework that we went over in class are posted on Moodle.

Questions of the Day:

• What the heck is this dimensional analysis thing all about?  Why should I care?
• What is the best way to practice for a chemistry quiz? 

                                    Answer: Practice, practice, practice!!!

Conversion Worksheet:  (these are the answers to the problems, the worksheet is on Moodle under handouts)

               
1. a

1.15 km     x     1,000 m     x     3.201 ft     x     12 in     =     45277.8 in     =     45,300 in
      1                   1 km                 1 m                 1 ft                     1

   b.

9.8 g     x     1 lb     x     1,000 mL     x     3.785 L     =     81.7747 lb     =     82 lb
1 mL           453 g               1 L                   1 gal                           gal                gal

2.

    1 in      ,     12 in
  2.54 cm         1 ft


For instructions on solving dimensional analysis problems, see post for 9/3.

Conversion Factors :

Mass:                                        Length:                                     Volume:
1 kilogram = 1,000 grams         1 kilometer = 1,000 meters        1 kiloliter = 1,000 liters
1 gram = 10 decigrams             1 meter = 10 decimeters             1 liter = 10 deciliters
1 gram = 100 centigrams          1 meter = 100 centimeters          1 liter = 100 centiliters
1 gram = 1,000 milligrams       1 meter = 1,000 millimeters        1 liter = 1,000 milliliters
1 kilogram = 2.2 lbs                 1 inch = 2.54 centimeters           1 liter = 1.057 quarts
1 lb = 16 oz.                             1 foot = 12 inches                      1 cup = 16 fluid oz.
1 lb = 454 grams                      1 mile = 5,280 feet                     1 fluid oz. = 29 milliliters
1 ton = 2,000 lbs                      1 mile = 1.609 kilometers           1 gallon = 4 quarts
                                                 1 meter = 1.094 yards                1 gallon = 8 pints
                                                 1 meter = 39.37 inches              1 gallon = 3.785 liters

Time :                           Temperature:
1 year = 52 weeks         F = 9/5 C + 32
1 week = 7 days            C = 5/9 (F - 32)
1 day = 24 hours
1 hour = 60 minutes
1 minute = 60 seconds

The practice worksheet for the quiz is on Moodle.  If you have trouble solving any of these problems, e-mail Mrs. Friedmann for tips.  If you had a conflict today and could not study for the quiz, contact Mrs. Friedmann and she will allow you to take it at a later time.

The next scribe post author is Pam H.