Question

1. A 5.75 mL sample of mercury has a measured mass of 77.05 g. The density is ___________

2. Mercury’s accepted density is 13.53 g·mL^-1. The % error in your measurement is: ____________

3.

Is this person accurate? ____                        Is the person precise? ___ Defend your answer!

4.

This molecule contains ____ elements and ____ atoms. Carbon=black    Oxygen=Red     White=Hydrogen The molecular formula for this substance is: ___________

5. Calculate the number of seconds in 5.25 years using unit analysis: (1 year = 365.25 days)

6. A calculator displays the answer to a problem as 53.29841

     Report this answer to:

            _______________      5 significant figures

            _______________      3 significant figures

            _______________      1 significant figure

7.

Which letter(s) represents: a) compound ____    b) pure element ____   c) Mixture of elements ____

                                          d) Mixture of compounds _____ e) a solid element ____

Answer 1

volume = 5.75ml
mass    = 77.05gm
density = mass/volume
        = 77.05/5.75
        = 13.4gm/ml
Mercury accepted density is 13.53g/ml
% error = (13.53-13.4)*100/13.53
         =0.96%
3. is this person accurate -No (not on the bull's eye)
Is the person precise Yes (closely grouped)
This molecule contains 3(C,H&O) elements and 12 atoms.
The molecular formula of the substance is C3H6O3
4. 5.25 years
1 year = 365 days
1 day = 24 hours
1 hour = 60 min
1 min = 60 seconds
5.25 years = 5.25*365*24*60*60 = 165677400 sec = 1.66*10^8 sec
6. 53.298   5 significant figures
   53.3     3 significant figure
   50       1 significant figure
7. a. compound --- c
   b. pure element ---e
   c. mixture of elements --e