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 Answers 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___