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1、Prentice Hall Chemistry 2005,Section Assessment AnswersChapter 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 correct me
2、asurements 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 always be
3、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 precision of the
4、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.Calculate the
5、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 playersb.0.070020 meterc.10,800 meters d.5.00 cubic meters,a.unlimited b.5c.3d.3,3.1 section assessment,15.Solve the following and exp
6、ress 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 4b.4.0 x 10-7c.107d.8.65 x 10-1e.1.9 x 10 14,3.2 section assessment,18.Whic
7、h 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:kg,g,mg;temperature:oC,K;energy:J,cal.,3.2 section assessment,20.Name the quantity
8、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 section assessment,21.See the chart on the next slide.,milli-,10-3,0.001,m,nano-,10-9,0.000000001,n,deci-,1
9、0-1,0.1,d,centi-,10-2,0.01,c,Prefix,Abbreviatedprefix,Powerof Ten,Powerof Ten Fraction,Expanded Fraction,Decimal Form,3.2 section assessment,22.List the following units in order from largest to smallest:m3,mL,cL,mL,L,dL.m3LdLcLmLmL,3.2 section assessment,23.What is the volume of a paperback book 21c
10、m 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 object.Weight is a measure of the force of gravity on an object.,3.2 section assessment,25.State the relationship between degrees Ce
11、lsius 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 section assessment,27.State the relationship between joules and calories.1J=0.2390 cal,3.3 section assessment,38.What happens to the numerical va
12、lue 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)changes;the actual size does not change.,3.3 section assessment,39.Why is dimensional analysis useful?Dimensional analysis provides an alternative approach
13、to problem solving.,3.3 section assessment,40.What types of problems can be solved using dimensional analysis?Conversion problems,3.3 section assessment,41.What conversion factor would you use to convert between these pairs of units?a.minutes to hoursb.grams to milligramsc.cubic decimeters to millil
14、iters,a.1hour/60 minb.103 mg/1 gc.103 mL/1 dm3,3.3 section assessment,42.Make the following conversions.Express your answers in standard exponential form.a.14.8 g to microgramsb.3.72 x 10-3 kg to gramsc.66.3L to cubic centimeters,a.1.48 x 107 ugb.3.72 gc.6.63 x 104 cm3,3.3 section assessment,43.An a
15、tom 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 gold,3.3 section assessment,44.Convert the following.Express your answers in scientific notation.a.7.5 x 104 to kilojoulesb.3.9 x 105 mg to decigramsc.2.21 x 10-4 dL to microliters,a.7.5 x 101
16、kJb.3.9 x 103 dgc.2.21 x 101 uL,3.3 section assessment,45.Light travels at a speed of 3.00 x1010 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 compositi
17、on of a substance,not on the size of the sample.density=mass/volume,3.4 section assessment,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
18、 the density of helium in grams per liter?1.7 x 10-2 g/L,3.4 section assessment,53.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 1
19、9.7 cm3 has a mass of 15.8g.Would this ball sink or float in a container of gasoline?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
20、50.0 g?The density of cough syrup is 0.950 g/cm3.52.6 cm3,3.4 section 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.,
