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1、Prentice Hall Chemistry 2005,Section Assessment Answers Chapter 3,Init c. 2010 by Abraham Paz, with subsequent modifications and additions by Daniel R. Barnes,Click here to jump to a specific section assessment,3.1 section assessment,9. How do measurements relate to experimental science? Making corr
2、ect measurements is fundamental to the experimental sciences.,3.1 section assessment,10. How are accuracy and precision evaluated? Accuracy is the measured value compared to the correct values. Precision is comparing more than one measurement.,3.1 section assessment,11. Why must a given measurement
3、always be reported to the correct number of significant figures? The significant figures in a calculated answer often depend on the number of significant figures of the measurements used in the calculation.,3.1 section assessment,12. How does the precision of a calculated answer compare to the preci
4、sion of the measurements used to obtain it? A calculated answer can not be more precise than the least precise measurement used in the calculation.,3.1 section assessment,13. A technician experimentally determined the boiling point of octane to be 124.1C. The actual boiling point of octane is 125.7C
5、. Calculate the error and the percent error. error = -1.6C; percent error = 1.3%,3.1 section assessment,14. Determine the number of significant figures in each of the following. a. 11 soccer players b. 0.070020 meter c. 10,800 meters d. 5.00 cubic meters,a. unlimited b. 5 c. 3 d.3,3.1 section assess
6、ment,15. Solve the following and express each answer in scientific notation and to the correct number of significant figures. a. (5.3 x 104) + (1.3 x 104) b. (7.2 x 10-4)/(1.8 x 103) c. 104 x 10-3 x 10 7 d. (9.12 x 10-1) (4.7 x 10-2) e. (5.4 x 104) x (3.5 x 10 9),a. 6.6 x 10 4 b. 4.0 x 10 -7 c. 107
7、d. 8.65 x 10 -1 e. 1.9 x 10 14,3.2 section assessment,18. Which five SI base units are commonly used in chemistry? m, kg, K, s, mol,3.2 section assessment,19. Which metric units are commonly used to measure length, volume, mass, temperature, and energy? Length: cm, m, km; volume: L, mL, cm3; mass: k
8、g, g, mg; temperature: oC, K; energy: J, cal.,3.2 section assessment,20. Name the quantity measured by each of the seven SI base units and give the SI symbol of the unit. length (m) mass (kg) temperature (K or oC) time (s) amount of substance (mol) luminous intensity (cd) electric current (A),3.2 se
9、ction assessment,21. See the chart on the next slide . . .,milli-,10-3,0.001,m,nano-,10-9,0.000000001,n,deci-,10-1,0.1,d,centi-,10-2,0.01,c,Prefix,Abbreviated prefix,Power of Ten,Power of Ten Fraction,Expanded Fraction,Decimal Form,3.2 section assessment,22. List the following units in order from la
10、rgest to smallest: m3, mL, cL, mL, L, dL. m3 L dL cL mL mL,3.2 section assessment,23. What is the volume of a paperback book 21cm tall, 12cm wide, and 3.5cm thick? 8.8 x 102 cm3,3.2 section assessment,24. State the difference between mass and weight. Mass is the measure of the amount of matter in an
11、 object. Weight is a measure of the force of gravity on an object.,3.2 section assessment,25. State the relationship between degrees Celsius and Kelvins. C = K - 273,3.2 section assessment,26. Surgical instruments may be sterilized by heating at 170 C for 1.5hr. Convert 170 C to Kelvins. 443K,3.2 se
12、ction assessment,27. State the relationship between joules and calories. 1J = 0.2390 cal,3.3 section assessment,38. What happens to the numerical value of a measurement that is multiplied by a conversion factor? What happens to the actual size of the quantity? The numerical value( and the unit) chan
13、ges; the actual size does not change.,3.3 section assessment,39. Why is dimensional analysis useful? Dimensional analysis provides an alternative approach to problem solving.,3.3 section assessment,40. What types of problems can be solved using dimensional analysis? Conversion problems,3.3 section a
14、ssessment,41. What conversion factor would you use to convert between these pairs of units? a. minutes to hours b. grams to milligrams c. cubic decimeters to milliliters,a. 1hour / 60 min b. 103 mg / 1 g c. 103 mL / 1 dm3,3.3 section assessment,42. Make the following conversions. Express your answer
15、s in standard exponential form. a. 14.8 g to micrograms b. 3.72 x 10-3 kg to grams c. 66.3L to cubic centimeters,a. 1.48 x 107 ug b. 3.72 g c. 6.63 x 104 cm3,3.3 section assessment,43. An atom of gold has a mass of 3.271 x 10-22g. How many atoms of gold are in 5.00 g of gold? 1.53 x 1022 atoms of go
16、ld,3.3 section assessment,44. Convert the following. Express your answers in scientific notation. a. 7.5 x 104 to kilojoules b. 3.9 x 105 mg to decigrams c. 2.21 x 10-4 dL to microliters,a. 7.5 x 101 kJ b. 3.9 x 103 dg c. 2.21 x 101 uL,3.3 section assessment,45. Light travels at a speed of 3.00x1010
17、 cm/sec. What is the speed of light in kilometers/hour? 1.08 x 109 km/h,3.4 section assessment,50. What determines the density of an object? Density is an intensive property that depends only on the composition of a substance, not on the size of the sample. density = mass/volume,3.4 section assessme
18、nt,51. How does density vary with temperature? Density generally decreases when temperature increases.,3.4 section assessment,52. A weather balloon is inflated to a volume of 2.2 x 103 L with 37.4g of helium. What is the density of helium in grams per liter? 1.7 x 10-2 g/L,3.4 section assessment,53.
19、 A 68-g bar of gold is cut into 3 equal pieces. How does the density of each piece compare to the density of the original gold bar? All the densities are equal.,3.4 section assessment,54. A plastic ball with a volume of 19.7 cm3 has a mass of 15.8g. Would this ball sink or float in a container of ga
20、soline? It would sink because the density of the ball, 0.802 g/cm3, is greater than the density of the gasoline.,3.4 section assessment,55. What is the volume, in cubic centimeters, of a sample of cough syrup that has a mass of 50.0 g? The density of cough syrup is 0.950 g/cm3. 52.6 cm3,3.4 section
21、assessment,56. What is the mass, in kilograms, of 14.0 L of gasoline? (Assume that the density of gasoline is 0.680 g/cm3.) 9.52 kg,Jump to 3.2 Section Assessment,Jump to 3.1 Section Assessment,Jump to 3.3 Section Assessment,Jump to 3.4 Section Assessment,Press your “End” button at any time to jump to this page.,