Chapters 3 & 4 Practice Test

 

1)     Give examples of the following four situations: precise and accurate, precise but not accurate, accurate but not precise, neither accurate nor precise.

 

              Remember, precise means repeatable or consistent, and accurate means right.

 

 

 

 

2)     Get a piece of 8 ½ × 11 paper and a ruler.  Describe the paper quantitatively and qualitatively.  List physical as well as chemical properties.

 

        Quantitative:  numbers      

        Qualitative:  descriptive

 

 

 

3)     The surface area of the above piece of paper is 602.42 cm2.  What’s your percent error?

 

        |your value – 602.42|                                                       

        --------------------------  × 100 = % error                                 

                    602.42

        Remember to do the subtraction sig figs before you do the division!

 

4)     Use your homework graph from problem #71 (chap 4) to predict the mass if the volume is 145 mL.

 

        If you haven’t done #71 yet, it’s time!

 

 

5)     What is density?  What are the usual units?  What are the characteristics of an object with high density?  Low density?

       

        No help on this one!

 

 

 

6)     List and Review your significant figures rules.

 

        Your lecture notes from before we got the text books should come in real handy here!

 

 

 

 

7)     Convert 25°C to Kelvin.  Convert 185 K to Celsius.

 

        Your magic number is 273.

 

 

 

8)     Using a ruler, calculate the volume of 12 oz soda can in cm3.  Compare your value to the mL value on the can.  Calculate your % error.  (Use v = π r2 h)  (1L = 0.264 gal, 4 quarts = 1 gal, 16 oz = 1 quart)

        Answer:   If r = 3.25 and h = 11, there’s 2.8% error

       

 

 

 

9)     Salt water has a density of 1.15 g/mL.  What is the mass of the water in a 55 gallon salt-water aquarium?  (1L = 0.264 gal)

        Answer:   2.40 × 105

 

 

 

 

 

 

10)   Transfer the above water to another tank with the dimensions of 1.5 m × 0.82 m × 0.91 m.  Will it overflow? If yes, by how much?  If no, how much to fill it up?

        Answer:   No, need 9.12 × 105 mL more

 

 

 

 

 

 

11)   Assume the above tank is full of liquid mercury.  How many moles is that?

        Answer:   7.54 × 104

 

 

 

 

 

12)   How much aluminum do I need to weigh out to get 2.75 moles?

        Answer:   74.2

 

 

 

 

 

13)   Hydrogen (H2) has a density of 0.08999 g/L.  How many moles of hydrogen were needed to fill the Hindenburg?  Her volume was 7,062,000 cubic feet.   (1 ft = 30.48 cm)

        Answer:   8.927 × 106

 

 

 

 

14)   The world record for the 100 meter sprint is 9.79 seconds.  What’s that speed in miles per hour?

        (1.61 km=1mi)

        Answer:   36.8