Significant Figures and Dimensional Analysis Review by awt10412

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									          Significant Figures and Dimensional Analysis Review
                                         Chemistry


Some helpful conversions:

1 inch = 2.54 cm        1 lb = 454 g               1 qt = 0.946 L
1 mi = 5280 ft          1 qt = 2 pt                4qt = 1 gal
You should also remember that 1 cc = 1 cm3 = 1 mL exactly.


Practice Problems:

   1. How many hours are in a year?

   2. If you are going 55 miles per hour, what is your speed in mm per second?

   3. Convert 3598 grams into pounds

   4. Convert 231 grams into ounces.

   5. A beaker contains 578 mL of water. What is the volume in quarts?

   6. A box measures 3.12 ft in length, 0.0455 yd in width and 7.87 inches in height.
      What is its volume in cubic centimeters?

   7. If the density of an object is 2.87 x 10-4 lbs/cubic inch, what is its density in g/mL?



A few more questions….sorry no answers for these, but you can look them up.

Who was the considered the Father of the Periodic Table?
What do you call the group of elements that Ag is found in?
What do you call the group of elements that U is found in?
What group of elements would elements in Group IIA tend to react the strongest with
and why?
Why specifically, is Francium more reactive than Lithium in the Group I elements?
Answers:

  1. x hrs = 1yr (365 days / 1 yr) (24 hrs / 1 day) = 8760 hrs

  2. x mm/s = 55 mi / 1 hr (5280ft / 1 mi)(12 in / 1 ft)(2.54 cm / 1 in)( 10 mm / 1 cm)

     (1 hr / 60 min)(1min / 60 sec) = 2.5 x 104 mm/s


  3. x lb = 3598 g (1lb/454 g ) = 7.93 lb

  4. x oz = 231 g (1lb/454 g) (16 oz/1lb) = 8.14 g


  5. x qt = 578 mL (1 L / 1000 mL) (1qt / 0.946 L) = 0.611 qt


  6. First convert everything to inches then calculate volume using V = L x W x H.
             x in = 3.12 ft (12 in / 1ft) = 37.4 in
             x in = 0.0455 yd (3 ft / 1 yd) ( 12 in / 1 ft) = 1.64 in
             V = 37.4 in x 1.64 in x 7.87 in = 483 in3

     Conversion of in3 to cm3 :
          (2.54 cm / 1 in)3 = (2.543 cm3 / 1 in3)

     Thus converting 483 in3 into cm3 :
           X cm3 = 483 in3 ( 2.543 cm3 / 1 in3) = 7.91 x 103 cm3


  7. x g/mL = (2.87 x 10-4 / 1 in3 )(454g / 1 lb)(1 in3 / 2.543 cm3)(1 cm3 / 1 mL)

            = 7.95 x 10-3 g/mL

								
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