# Hw1_New - CHM 2045 FIRST PROBLEM SET INSTRUCTOR: DON...

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Hw1_New.wpd 09/27/10 CHM 2045 FIRST PROBLEM SET INSTRUCTOR: DON SWIETER OFFICE: K–223 PHONE: 395–5303 MATH REVIEW and SIGNIFICANT FIGURE QUESTIONS 1. Perform the indicated algebra: (For help see the appendices in your text.) a. a × a = b. a ÷ a = c. a = d. a = m n (m+3) (2m+2) 0 –2 e. Since a = , what does a = ? ¼ 1/n 2. How many significant figures are in each of the following? a. 9 baseballs b. 90 baseballs c. 9,000,000 baseballs d. 3 dozen ostrich eggs e. 0.1 cm f. 100.10 cm g. 1.01 in. h. 0.005 g i. 0.00500 g 3. Rewrite the values in problem 2 e-i in suitable scientific notation. 4. Do the indicated arithmetic paying strict attention to significant figures and units. a. 0.034 cm + 0.0340 cm b. 0.034 cm × 0.0340 cm c. 0.034 cm 0.0340 cm d. 0.034 cm ÷ 0.034 cm e. 0.034 cm 0.0034 cm 5. Perform the following calculations and report the answer to the proper number of significant figures (without the aid of a calculator): a. 9.75 in + 0.326 in b. 1.025 sec 0.09 sec c. (1.61 × 10 A) + (1.61 × 10 A) 15 16 d. (5.6 × 10 m) e. –2 2 6. Perform the following SI conversions making proper use of unit conversion analysis: a. 971 mg = kg b. 82 s = ms c. 12.3 cm = mm 22 d. 0.213 L = cm e. 6.50 m = cm f. 7.61 kg/L = mg/mL 3 –1 –1 7. You are given 1000 equal sized gem stones with a total mass of exactly 3 g. These gems are valued at \$1000 per oz. (Note: 1.00 oz = 28.35 g) Answer the following using unit – factor analysis. a. How much money are you out if you lose 50 stones? b. If you now receive an additional handful of these gems, how would you determine the value of this handful by weighing? Tell exactly how you would go about it. c. Could you determine the value of this handful by a counting procedure? What assumption would the counting procedure depend upon? 8. A circular cheese pizza with a 10" diameter sells for \$5.00. The same pizza with a 14" diameter sells for \$10.00. Which is the better buy? (Remember: area of a circle = ð r) 2 9. Medium thin-rind grapefruit (diam. = 2.0") sell for 10¢ each. Large thin-rind grapefruit (diam. = 3.0") sell for 20¢ each. Consider the fruit to be spherical. Which is the better buy? (Remember: volume of a sphere = 4/3 ð 3

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2 QUESTIONS ON MATTER and ENERGY 10. What are the general properties of metals and where are they found in the periodic table? 11. What are the general properties of nonmetals and where are they found in the periodic table? 12. Characterize each of the following as a physical or chemical process: a. copper wire produced from a bar of copper b. the attraction of an iron nail by a magnet c. dissolving sugar in water d. vaporization of water from a lake e. combustion of coal f. heating the filament of an incandescent lamp to provide light g. crystallization of sodium carbonate from water h. dissolving an Alka-Seltzer in water i. silver tarnishing in air 2 13. Suppose I define a new temperature scale (Hokie, °H) where the freezing point of H O is –40°H and 2 the boiling point of H O is 320°H. To what temperature in °C does 100°H correspond? From a significant figure standpoint, which scale the °H or the °C more precisely defines the temperature? Why?
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## This homework help was uploaded on 12/07/2011 for the course CHM 2045 taught by Professor Weinstein during the Fall '11 term at Santa Fe College.

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Hw1_New - CHM 2045 FIRST PROBLEM SET INSTRUCTOR: DON...

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