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C02 06/28/2012 11:24:59 Page CHAPTER STANDARDS FOR MEASUREMENT SOLUTIONS TO REVIEW QUESTIONS The exponent will be positive for a large number and negative for a small number The exponent will decrease The last digit in a measurement is uncertain because if the quantity were to be measured multiple times, the last digit would vary It must be written in scientific notation as 6:420  105 g Zeroes are significant when they are between non-zero digits or at the end of a number that includes a decimal point Rule When the first digit after those you want to retain is or less, that digit and all others to its right are dropped The last digit retained is not changed Rule When the first digit after those you want to retain is or greater, that digit and all others to the right of it are dropped and the last digit retained is increased by one No, the number of significant digits in the calculated value may not be more than the number of significant figures in any of the measurements Yes, the number of significant digits depends on the precision of each of the individual measurements and the calculated value may have more or fewer significant figures than the original measurements as long as the precision is no greater than the measurement with the lowest precision An example of a calculation with an increase in significant figures is in example 2.9 100 cm ¼ m 1m 1,000,000,000 nm ẳ 10,000,000 nm cmị 100 cm m 1,000,000,000 nm ¼ m 10 1000 mg ¼ g 1000 g ¼ kg 1000 g kgị kg 1000 mg ẳ 1,000,000 mg g 11 Weight is a measure of how much attraction the earth’s gravity has for an object (or person) In this case, the farther the astronaut is from the earth the less gravitational force is pulling on him or her Less gravitational attraction means the astronaut will weigh less The mass of the astronaut is the amount of matter that makes up him or her This does not change as the astronaut moves away from the earth 12 They are equivalent units - - C02 06/28/2012 11:24:59 Page - Chapter 2:54 cm 13 3:5 in:ị ẳ 8:9 cm in: 14 Heat is a form of energy, while temperature is a measure of the intensity of heat (how hot the system is) 15 The number of degrees between the freezing and boiling point of water are Fahrenheit Celsius Kelvin 180 F 100 C 100 K 16 The three materials would sort out according to their densities with the most dense (mercury) at the bottom and the least dense (glycerin) at the top In the cylinder, the solid magnesium would sink in the glycerin and float on the liquid mercury 17 Order of increasing density: ethyl alcohol, vegetable oil, salt, lead 18 The density of ice must be less than 0.91 g=mL and greater than 0.789 g/mL 19 Density is the ratio of the mass of a substance to the volume occupied by that mass Density has the units of mass over volume Specific gravity is the ratio (no units) of the density of a substance to the density of a reference substance (usually water at a specific temperature for solids and liquids) Specific gravity has no units 20 The density of water is 1.0 g=mL at approximately 4 C However, when water changes from a liquid to a solid at 0 C there is actually an increase in volume The density of ice at 0 C is 0.917 g=mL Therefore, ice floats in water because solid water is less dense than liquid water 21 If you collect a container of oxygen gas, you should store it with the mouth up Oxygen gas is denser than air 22 density of gold ¼ 19.3 g=mL mL 25 g goldị ẳ 1:3 mL 19:3 g mL 25 g silverị ẳ 2:4 mL 10:5 g density of silver ¼ 10.5 g=mL 25 g of silver has the greater volume - - C02 06/28/2012 11:24:59 Page - Chapter - SOLUTIONS TO EXERCISES (a) (b) (c) (d) (e) kilogram ¼ 1000 grams centimeter ¼ 1=100 of a meter (0.01 m) microliter ¼ 1=1,000,000 of a liter (0.000001 L) millimeter ¼ 1=1000 of a meter (0.001 m) deciliter ¼ 1=10 of a liter (0.1 L) (a) (b) (c) 1000 meters ¼ kilometer 0.1 gram ¼ decigram 0.000001 liter ¼ microliter (d) (e) (a) (b) (c) gram ¼ g microgram ¼ mg centimeter ¼ cm (d) micrometer ¼ mm (e) milliliter ¼ mL (f) deciliter ¼ dL (a) (b) (c) milligram ¼ mg kilogram ¼ kg meter ¼ m (d) nanometer ¼ nm ˚ (e) angstrom ¼ A (f) microliter ¼ mL (a) (b) (c) (d) (e) (f) 2050 9.00  102 0.0530 0.075 300 285.00 the first zero is significant; the last zero is not significant zeros are significant the first two zeros are not significant; the last zero is significant zeros are not significant zeros are significant zeros are significant (a) (b) (c) (d) (e) (f) 0.005 1500 250 10.000 6.070  104 0.2300 zeros are not significant zeros are not significant zero is significant zeros are significant zeros are significant the first zero is not significant; the last two zeros are significant 0.01 meter ¼ centimeter 0.001 liter ¼ milliliter Significant figures (a) 0.025 (b) 22.4 (2 sig fig.) (3 sig fig.) (c) (d) 0.0404 5.50  103 (3 sig fig.) (3 sig fig.) Significant figures (a) 40.0 (b) 0.081 (3 sig fig.) (2 sig fig.) (c) (d) 129,042 4.090  10À3 (6 sig fig.) (4 sig fig.) Round to three significant figures (a) 93.2 (b) 0.0286 (c) (d) 4.64 34.3 10 Round to three significant figures (a) 8.87 (b) 21.3 (c) (d) 130 (1.30  102) 2.00  106 - - C02 06/28/2012 11:24:59 Page - Chapter 11 Exponential notation (a) 2.9  106 (b) 5.87  10À1 (c) (d) 8.40  10À3 5.5  10À6 12 Exponential notation (a) 4.56  10À2 (b) 4.0822  103 (c) (d) 4.030  101 1.2  107 13 (a) (b) (c) (d) (e) (f) 14 (a) 12:62 1:5 0:25 14:37 ¼ 14:4 À ÁÀ Á 2:25  103 4:80  104 ¼ 10:8 107 ẳ 1:08 108 452ị6:2ị ẳ 195:97 ẳ 2:0  102 14:3 (0.0394) (12.8) ¼ 0.504 0:4278 ¼ 0:00718 ẳ 7:18 103 59:6 10:4 ỵ 3:75ị 1:5 104 ẳ 5:6 104 15:2 2:75 15:67 28:1 (b) (4.68) (12.5) ¼ 58.5 (c) 182:6 ¼ 40 4:6 (d) 1986 23:84 0:012 2009:852 ¼ 2010: ¼ 2:010  103 (e) (f) 29:3 ¼ 2:49  10À4 ð284Þð415Þ À ÁÀ Á 2:92  10À3 6:14  105 ¼ 1:79  103 15 Fractions to decimals (3 significant figures) (a) (b) ¼ 0:833 ¼ 0:429 (c) (d) - - 12 ¼ 0:750 16 ¼ 0:500 18 C02 06/28/2012 11:25:0 Page - Chapter 16 Decimals to fractions (a) 0:25 ¼ (b) 0:625 ¼ 17 (a) (d) 3:42x ¼ 6:5 x¼ (b) (c) (c) 6:5 ¼ 1:9 3:42 x ¼ 7:05 12:3 or 3 0:888 ¼ 0:525 ¼ 0:25 x 0:525 ¼ 0:25x 0:525 x¼ ¼ 2:1 0:25 1:67 ¼ x ¼ 7:05ị12:3ị ẳ 86:7 18 (a) (b) 19 (a) (b) (c) (d) (e) (f) (g) (h) 212 À 32 1:8 x ¼ 1:0  102 g 40:90 g 8:9 ¼ mL x g x ¼ 40:90 g 8:9 mL 40:90 g x¼ g ¼ 4:6 mL 8:9 mL x ẳ 72 ẳ 1:8x ỵ 32 (c) 72 32 ¼ 1:8x 40: ¼ 1:8x 40: ¼x 1:8 22 ¼ x 1m 28:0 cmị ẳ 0:280 m 100 cm km ẳ 1:000 km 1000: mị 1000 m 10 mm 9:28 cmị ẳ 92:8 mm cm 1000 mg ¼ 1:068  104 mg ð10:68 gÞ 1 g À Á 1g kg 6:8  10 mg ¼ 6:8  10À2 kg 1000 mg 1000 g kg ð8:54 gị ẳ 0:00854 kg 1000 g 1L 25:0 mLị ẳ 2:50 102 L 1000 mL 10 mL 22:4 Lị ẳ 2:24 107 mL 1L - - C02 06/28/2012 11:25:0 Page 10 - Chapter 20 (a) (b) (c) (d) (e) (f) (g) (h) 21 (a) (b) (c) (d) (e) (f) 22 (a) (b) (c) (d) ! ˚ 1m 1A ˚ ¼ 4:5  108 A ð4:5 cmÞ 100 cm 10À10 m À9 10 m 100 cm ð12 nmị ẳ 1:2 106 cm nm 1m 1000 m 1000 mm 8:0 kmị ẳ 8:0  106 mm km 1m 1g ð164 mgị ẳ 0:164 g 1000 mg 1000 g 1000 mg 0:65 kgị ẳ 6:5 105 mg kg 1g 1000 g 5:5 kgị ẳ 5:5  103 g kg 1000 mL 0:468 Lị ẳ 468 mL 1L 1L 1000 mL ẳ 9:0 103 mL 9:0 mLị 1L 106 mL 2:54 cm ¼ 107 cm ð42:2 in:Þ in: 5280 ft 12 in: 0:64 miị ẳ 4:1 104 in: mi ft 2:54 cm 2 ð2:00 in: Þ ¼ 12:9 cm2 in: 2:205 lb ð42:8 kgị ẳ 94:4 lb kg 946 mL 3:5 qtị ẳ 3:3 103 mL qt qt gal 20:0 Lị ẳ 5:29 gal 0:946 L qt The conversion is: m ! cm ! in: ! ft 100 cm in: ft ẳ 117 ft 35:6 mị 1m 2:54 cm 12 in: mi ¼ 10:3 mi ð16:5 kmÞ 1:609 km 2:54 cm 10 mm 3 4:5 in: ị ẳ 7:4  104 mm3 in: cm 453:6 g 95 lbị ẳ 4:3 104 g lb - 10 - C02 06/28/2012 11:25:1 Page 11 - Chapter - (e) (f) 23 24 qt 0:946 L 20:0 galị ẳ 75:7 L gal qt The conversion is: ft3 ! in:3 ! cm3 ! m3 À Á 12 in: 2:54 cm m 4:5  10 ft ¼ 1:3  103 m3 ft in: 100 cm mi km km ! ! The conversion is: min hr 15:2 mi 1:609 km 60 km ¼ 33 45 mi hr hr km mi mi ! ! The conversion is: s s hr 5:0 km mi 3600 s mi ¼ 12 923 s 1:609 km hr hr 25 The conversion is: L ! mL ! mg ! g 1000 mL 500: mg 1g Lị ẳ 5:00 g 1L 100: mL 1000 mg 26 The conversion is: tablet ! g ! mg ! grains 0:500 g 1000 mg grain tabletị ẳ 8:33 grains tablet 1g 60 mg 27 The conversion is: hr ! ! s ! m ! km ! mi 60 60 s 0:11 m km mi hoursị ẳ 1:2 miles hr 1s 1000 m 1:61 km 28 The conversion is: cm ! in ! ft ! yr ! day in: ft yr 365 day cmị ẳ 3:54 days 2:54 cm 12 in: 3:38 ft yr 29 The conversion is: lb body ! lb fat ! kg fat 11:2 lb fat kg ð225 lb bodyị ẳ 11:4 kg fat 100 lb body 2:205 lb 30 The conversion is: carats ! mg ! g ! lb 200 mg 1g lb 5:75 caratsị ẳ 2:54 103 lb carat 1000 mg 453:6 g 31 yd mi km m m ! ! ! ! The conversion is: s s s s 100: yd mi 1:609 km 1000 m 60 s m ¼ 1:1  102 52 s 1760 yd mi km min - 11 - C02 06/28/2012 11:25:1 Page 12 - Chapter 32 mi km m cm cm ! ! ! ! The conversion is: hr hr hr hr s 133 mi 1:609 km 1000 m 100 cm hr cm ¼ 5:94  103 hr mi km 1m 3600 s s 33 (a) (b) 34 (a) (b) 29,035 ft 21,002 ft ẳ 8033 total feet climbedị 60 16 hrị ẳ 960 960 þ 42 ¼ 1:0  103 hr 8003 ft mi mi ¼ 1:5  10À3 1:0  10 5280 ft 8003 ft mi 1:609 km 1000 m m ¼ 4:1  10À2 mi km 60 s s 1:0  10 5280 ft m cm in: ft hr ! ! ! The conversion is: ! hr hr hr hr min 4500 m 100 cm in: ft hr ft ¼ 50 hr m 2:54 cm 12 in: 60 min m km hr ! ! The conversion is: ! hr m min s 4500 m km hr km ¼  10À4 hr 1000 m 60 60 s s 35 The conversion is: gal ! qt ! L ! mL ! cup qt 1L 1000 mL cup 2010 galị ẳ 1:60 104 cups coffee gal 1:06 qt 1L 473 mL 36 The conversion is: lb ! g ! number of tilapia À Á 454 g tilapia 4:75  106 lb ¼ 4:03  106 tilapia lb 535 g 37 The conversion is: gal ! qt ! mL ! drops qt 946 mL 20: drops ¼ 7:6  104 drops ð1:0 galÞ gal qt mL 38 The conversion is: gal ! qt ! L qt 0:946 L ẳ 160 L 42 galị gal qt 39 The conversion is: ft3 ! in:3 ! cm3 ! mL 12 in: 2:54 cm mL 1:00 ft ị ẳ 2:83  104 mL ft in: cm3 - 12 - C02 06/28/2012 11:25:2 Page 13 - Chapter 40 V¼Âh A ¼ area h ¼ height V ¼ volume cm cm The conversion is: ! ! m2 nm m V 200 cm3 nm 1m A¼ ¼ ¼  105 m2 0:5 nm h 10À9 m 100 cm 41 (a) (b) (c) (27 cm) (21 cm) (4.4 cm) ¼ 2.5 103 cm3 1L 2:5  103 cm3 is 2:5  103 mL ¼ 2:5 L 1000 mL À Á in: 3 ¼ 1:5  102 in:3 2:5  10 cm 2:54 cm 2:54 cm 1L qt gal 42 16 in:ị8 in:ị10 in:ị ẳ gal in: 1000 mL 0:946 L qt 43 (a) (b) 44 F ẳ 1.8 C ỵ 32 ẳ (1.8) (38.8) ỵ 32 ẳ 101.8 F Yes, the child has a fever since 101.8 F > 98.6 F F ẳ 1.8 C ỵ 32 162 32 ẳ 72:2 C 1:8 45 (a) (b) (c) (d) 46 (a) (b) (c) (d) (1.8) (45) ỵ 32 ẳ 113 F Remember to express the answer to the same precision as the original measurement: 0:0 32 ỵ 273 ẳ 255:2 K 1:8 1.8(18) ỵ 32 ẳ 0.40 F 212 273 ẳ 61 C C ỵ 273 ẳ K 1.8(32) þ 32 ¼ 90. F À8:6 À 32 ¼ À23 C 1:8 273 ỵ 273 ẳ 546 K C ẳ 100 273 ẳ 173 C 173ị1:8ị ỵ 32 ¼ À279 F ¼ À300 F 47 Summer! F ẳ C F ẳ 1:8 Cị ỵ 32 F ẳ 1:8 Fị ỵ 32 significant figure in 100 Kị substitute F for C 32 ẳ 0:8 Fị 32 ẳ F 0:8 40 ẳ F À40 F ¼ À40 C - 13 - C02 06/28/2012 11:25:2 Page 14 - Chapter 48 F ¼ C F ẳ 1:8 Cị ỵ 32 substitute C for F C ẳ 1:8 Cị ỵ 32 2:8 Cị ẳ 32 32 2:8 Cẳ C ¼ À11:4 À11:4 C ¼ 11:4 F 49 F ẳ 1:8 C ỵ 32 50 Cẳ F 32 1:8 1:8ị460ị ỵ 32 ẳ 860 F 244ị 32 ẳ 153 C 1:8 51 d ¼ m 59:82 g g ¼ ¼ 0:920 v 65:0 mL mL 52 d ¼ m 20:41 g g ¼ ¼ 0:810 v 25:2 mL mL 53 50:92 g À 25:23 g ẳ 25:69 g mass of liquidị m 25:69 g g d¼ ¼ ¼ 1:03 v 25:0 mL mL 54 54:6 mL À 50:0 mL ¼ 4:6 mL ðvolume of zincị m 32:95 g g dẳ ẳ ẳ 7:2 v 4:6 mL mL 55 The conversion is g ! mL mL 15 gị ẳ 16 mL 0:929 g 56 The conversion is g ! mL mL 75 gị ẳ 63 mL 1:20 g 57 (a) (b) (c) 58 (a) (b) (c) report 10.01 grams report 10.012 grams report 10.0124 grams 1:134 g Skittle 175 Skittlesị ẳ 198 g Skittles Skittle 5:3 mL Skittles L Skittles ð175 Skittlesị ẳ 0:15 L Skittles Skittles 1000 mL Skittles Skittle 325:0 g Skittlesị ẳ 286:6 Skittles 1:134 g Skittles - 14 - C02 06/28/2012 11:25:2 Page 15 - Chapter - (d) (e) 1000 mL Skittles Skittles 0:550 L Skittlesị ẳ 620 Skittles L Skittles 5:3 mL Skittles The mass measurement is more precise It is also more accurate Using calculations similar to those above there should be 309 Skittles in 350 grams and the average value is 310 Skittles There should be 367 Skittles in 325 L of Skittles and the average value is 384 Skittles 59 A graduated cylinder would be the best choice for adding 100 mL of solvent to a reaction While the volumetric flask is also labeled 100 mL, volumetric flasks are typically used for doing dilutions The other three pieces of glassware could also be used, but they hold smaller volumes so it would take a longer time to measure out 100 mL Also, because you would have to repeat the measurement many times using the other glassware, there is a greater chance for error 60 The conversion is: g ! mL mL 21:5 gị ẳ 14:5 mL 1:484 g 61 The conversion is: g ! mL mL ¼ 26:05 mL ð25:27 gÞ 0:97 g 62 The conversion is: day ! cups ! mg ! g ! lb 4:00  108 cups 160 mg 1g lb dayị ẳ 105 lb day cup 1000 mg 453:6 g 63 Mass of gear carried by paladin after drinking strength potion ¼ 115 lb þ 50:0 lb ¼ 165 lb Amount of mass potion paladin can carry ¼ 165 lb À 92 lb ¼ 73 lb The conversion is: lb ! g ! mL ! vials potion 454 g ml vial potion 73 lbị ẳ 3:43 vials potion lb 193 g 50:0 mL You would only be able to collect only vials, because would put you over your mass limit 64 The conversion is: sequins ! cm3 ! g ! kg 0:0241 cm3 41:6 g sequins kg 4560 sequinsị ẳ 4:57 kg sequins cm3 1000 g sequin The conversion is: kg ! lb 2:20 lb ð4:57 kg sequinsị ẳ 10:1 lb sequins kg 65 V ¼ side3 ¼ ð0:50 mÞ3 ¼ 0:13 m3 100: cm 1L ¼ 130 L ð0:13 m Þ m 1000 cm3 ðvolume of the cubeÞ ðvolume of cubeÞ - 15 - C02 06/28/2012 11:25:3 Page 16 - Chapter Yes, the cube will hold the solution 130 L À 8.5 L ¼ 120 L additional solution is necessary to fill the container 66 mg mg mg ! The conversion is: ! m L day 180 mg 1m L ¼ 4000 mg ingested=day  10 m3 day 1000 L ð1 sig: figureÞ Yes, the nurse is at risk This is well over the toxic limit 67 (a) Convert 20:27 K to C K À 273:15 ¼ C 20:27 K À 273:15 ¼ À252:88 C (b) 68 Convert 20:27 K to F F ¼ ð1:8 Cị ỵ 32 F ẳ 1:8 252:88ị þ 32 ¼ À455:18 þ 32 F ¼ À423:18 F F ẳ 1:8 C ỵ 32 Convert 36 C to F 1:8ị36ị ỵ 32 ẳ 97 F Convert 38 C to F 1:8ị38ị ỵ 32 ẳ 100 F Sauropods have a body temperature close to the body temperature of other warm-blooded mammals such as dogs, humans, and cows 69 The conversion is: L ! dL ! mg ! g 10 dL 130 mg 1g ẳ 6:1 g 4:7 Lị 1L dL 1000 mg 70 A sample of gold will sink to the bottom of the mercury and a sample of iron pyrite will float 71 The conversion is: hands ! in: ! cm ! m in: 2:54 cm 1m ẳ 1:44 m 14:2 handsị hand in: 100 cm 72 The conversion is: days ! hr ! gal ! qt ! L 24 hr 22:5 gal qt 0:946 L ¼ 5:1  103 L ð30 daysÞ day 12 hr gal qt 73 d ¼ m The cube with the largest volume has the lowest density Use Table 2.5 V Cube A - lowest density Cube B Cube C - highest density 1.74 g/mL - magnesium 2.70 g/mL - aluminum 10.5 g/mL - silver - 16 - C02 06/28/2012 11:25:3 Page 17 - Chapter 74 The conversion is: ft ! in ! cm ! m ! nm ! nanotubes 12 in: 2:54 cm 1m 10 nm nanotube ð40:0 ftÞ ¼ 9:4  109 nanotubes ft in: 100 cm 1m 1:3 nm 75 The conversion is: acres ! ft2 ! mi2 ! km2 43560 ft2 mi 1:609 km 125 acresị ẳ 0:506 km2 5280 ft mi acre 76 The volume of the aluminum cube is: V¼ m 500: g ¼ g ¼ 185 mL d 2:70 mL Density of Al is 2:70 g=mL This is the same volume as the gold cube thus: m ẳ dV ẳ 185 mLị19:3 g=mLị ẳ 3:57 103 g of gold m 24:12 g 0:965 g ¼ ¼ V 25:0 mL mL Density of Au is 19:3 g=mL ðdensity of water at 90 Cị 77 dẳ 78 150:50 g 88:25 g ẳ 62:25 g m m 62:25 g d ¼ thus V ¼ ¼ g ¼ 49:8 mL V d 1:25 mL ðmass of liquidÞ ðvolume of liquidÞ The container must hold at least 50 mL 79 H2 O alcohol 50 g g ¼ 50 mL 1:0 mL 50 g g ¼ 60 mL 0:789 mL Ethyl alcohol has the greater volume due to its lower density 80 The conversion is: g ! lb ! oz lb 16 oz ẳ 0:29 oz 8:1 gị 453:6 g lb 3:5 % Mn 0:29 ozị ẳ 0:010 oz Mn 100 ðmass of the coinÞ 81 Volume of sulfuric acid mL 100: gị ẳ 54:3 mL 1:84 g - 17 - 06/28/2012 11:25:3 Page 18 - Chapter 82 The conversion is: cup ! oz ! qt ! L ! mg 10 oz coffee qt coffee L coffee 31:4 mg NMP 2:00 cup coffeeị ẳ 18:6 mg NMP cup coffee 32 oz coffee 1:057 qt coffee L coffee 83 1000 g 1:00 mL ð1:00 kg Pdị ẳ 83:3 mL Pd at 20 C kg 12:0 g 1000 g 1:00 mL ð1:00 kg Pdị ẳ 90:9 mL Pd at 1550 C kg 11:0 g 90:9 mL À 83:3 mL ¼ 7:6 mL change in volume 84 m , as the volume increases, the density decreases V As solids are heated the density decreases due to an increase in the volume of the solid Since d ¼ Density C02 Temperature 85 Original Apple computer $ 9995 Mbyte $2:0  10À3 ¼ byte 5:0 Mbytes 106 byte iPod II $ 699 Gbyte $1:1  10À8 ¼ 64 Gbytes 10 byte byte The iPod is definitely a better buy! mL 86 V ¼ ð2:00 cmị15:0 cmị6:00 cmị ẳ 180:mL volume of barị cm3 m d ¼ ¼ 3300 g=180: mL ¼ 18:3 g=mL V The density of pure gold is 19.3 g/mL (from Table 2.5), therefore, the gold bar is not pure gold, since its density is only 18.3 g/mL, or it is hollow inside 87 m ¼ dV ¼ (0.789 g/mL) (35.0 mL) ẳ 27.6 g ethyl alcohol 27.6 g ỵ 49.28 g ¼ 76.9 g (mass of cylinder and alcohol) - 18 - C02 06/28/2012 11:25:3 Page 19 - Chapter 88 The conversion is g ! oz ! gr ! scruples 12 oz 480 gr scruple 695 gị ẳ 537 scruples 373 g oz 20 gr 89 The conversion is: days ! teaspoons ! mL teaspoons  mL ¼ 400 mL ð10 daysÞ day teaspoon Since you will need a total of 400 mL for the 10 days and the bottle contains 500 mL, you have purchased enough 90 The density of lead is 11.34 g/mL The density of aluminum is 2.70 g=mL The density of silver is 10.5 g=mL The density of the unknown piece of metal can be calculated from the mass (20.25 g) and the volume (57.5 mL À 50 mL ¼ 7.5 mL) of the metal Density of the unknown metal ¼ 20.25 g=7.5 mL ¼ 2.7 g/mL The metal must be aluminum 91 30:7 mL À 25:0 mL ¼ 5:7 mL m 15:454 g ¼ 2:7 g=mL Density of slug d¼ ¼ V 5:7 mL Mass of liquid; cylinder; and slug 125:934 g Volume of slug Mass of slugðsubtractÞ À15:454 g Mass of cylinderðsubtractÞ À89:450 g Mass of the liquid 21:030 g m 21:030 g ¼ 0:841 g=mL Density of liquid d ¼ ¼ V 25:0 mL 92 The conversion is: km ! m ! cm ! in ! ft ! mi ! hr ! ! s ! ns 1000 m 100 cm in: ft mi hr 60 60 s ð730:0 kmÞ km 1m 2:54 cm 12 in: 5280 ft 1:86  108 mi hr 10 ns ¼ 8:78  106 ns 1s 8780000 ns is good to only sig figs You would need at least significant digits to detect the difference between 8780000 ns and (8780000 ỵ 60) ns Sometimes experimenters not see differences due to the precision of their measuring techniques - 19 - ... 350 grams and the average value is 310 Skittles There should be 367 Skittles in 325 L of Skittles and the average value is 384 Skittles 59 A graduated cylinder would be the best choice for adding... and a sample of iron pyrite will float 71 The conversion is: hands ! in: ! cm ! m in: 2:54 cm 1m ẳ 1:44 m 14:2 handsị hand in: 100 cm 72 The conversion is: days ! hr ! gal ! qt ! L... substance to the density of a reference substance (usually water at a specific temperature for solids and liquids) Specific gravity has no units 20 The density of water is 1.0 g=mL at approximately
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