CHM 2045C Module Two Sample Exam Answers

Module Two: ChemMath and Measurement (Chapter 1)

A. _____(03) Significant Figures-Section 1.7  Answers abc

B. _____(03) Round Off/Math of Significant Figures-appendix A.2

C. _____(04) Scientific Notation  Appendix A.2

D. _____(04) Metric Basic Units /Numerical Prefixes-Section 1.7. Answers de

E. _____(05) Metric System Conversion Factors-Sect 1.7,C.1, C.2,C.3

F. _____(10) Unit Analysis Problems 1.7, 1.8 Answers fh

G. _____(08) Temperature Conversion 1.3  gh

H. _____(08)  Density/Specific Gravity Calculations 1.3

M. _____(10) Multiple Choice(Measurement) Chapter 1&2 (Answers at the Bottom)

_______(55) Total = ______%

Module Two: Sample Pretest

Module Two-Part A: Significant figures (1.7)     3 points ANSWERS

In the blank, state the number of significant figures in each of the following measurements:

__1__1.  0.05 mL                                         ___1__4.  1000 g

__4__2.  250.0 cm                                       ___4__5.  0.00006500 moles

__3__3.   456,000,000 people                   __3___6. 0.00200 kg

Module Two-Part B: Rounding Off & Arithmetic Operations of Sign. Figures     3 points

Round off the following numbers to three significant figures:

(1) 1.598 x 106= _1.60 x 106__       (2) 0.000 000 484 500 = ___4.85 x 10 -7____

Perform the following addition/multiplication operations and express the answer using the proper units and significant figures:

(3)    4       mL                         (4)    16.5 cm             (5)       12.0  g ÷ 1.00 g = 12.0

16.3    mL                              X    1.7 cm                    or

+     0.953 mL                                          28 cm2                12.0  g / 1.00 g = 12.0

21 mL

Module Two-Part C: Exponential Numbers and Scientific Notation 3 points

(1.6 & 1.&) Express the following ordinary numbers in scientific notation (If greater than three significant figures, round off to three significant figures:

(1) 1,010,100,000,000, 000  = _1.01 x 10 15_    (4) 0.0001198 = _1.20 x 10 -4___

(2) 0.000 000 000 000 019   =  _1.9 x 10 -14_   (5) 1,000,000 = __1 x 10 6______

(3)                           456,789   = __4.57 x 10 5_  (6) 0.000200  = __2.00 x 10 -4___