Worksheet 1 Key - Chem 142, Winter 2012 Name Group Activity...

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Unformatted text preview: Chem 142, Winter 2012 Name Group Activity 1: Significant Figures, Units, and Conversion Factors 1. A. How many significant figures are in each of the following. numbers? 5.40 3 3.97 x 10'5 ’5 30000 ___\___ 250. 3 1.4895 5 1.400 L’l 235.40 _ 5 I ‘8. Complete the foliowing calculations to the appropriate number of sig. figs: 234.52 + 25.2 = A $01,? ' 1420' x 320. = ’4. 5‘! x IO; (6.274X103) x (1.55x10‘2) = 5143172610. 2. 0/7.? ' 529 + 1.30 = L107 430. - 44.67 =_ 58 I; (1.343x102) + (1.5654x102) =2 . 7082/01: 0/0, 8 10f4 Chem 142, Autumn 2011 l l l i "l 2. The average speed (um) of a collection of gaseous molecules is given by the following formula: urms = where Tis the temperature of the sample, Mis the molar mass of the gaseous compound, and R is a constant related to the distribution of the available kinetic energy over the molecules in the sample (R = 8.314J mol’1 K'l). What is um for v nitrogen gas (M = 28.02 g mol'l) at 298.15 K? ' 20f4 ' Chem 142, Autumn 2011 3. Methanol (methyl alcohol or wood alcohol) is a potential automotive fuel, either in pure form or mixed with gasoline. Some fleet vehicles, such as municipal buses, have been modified to burn methanol-containing fuels. These fuels are also used by some fleecm.A ' ' " ' a 1 0 n n no II 15.0% gasoline by mass gets 25.5 mi/gal. The fuel has a density of 0.775 g/mL. How many kilograms of methanol does the automobile consume in a trip of 808 km? lml x 1%“: l760yd‘ R§.$/M.' ,c 3?, . .f’l cl- XW- l L35. '3of4 : l5l.(pcl§0l “cons “Fuel (9 $13 kaNe/H’Imipl Chem 142, Autumn 2011 Potentially helpful information. Conversion factors: Length 1 m = 1.094 yd 1 mi = 5280 ft 1 ft = 12 in * 1km=103m 1mi=1760yd 1A=10'1°m 1 m = 102 cm (centimeters) 1 in = 2.54 cm (exact) 1 m = 103 mm (millimeters) Mass 1 kg = 2205 lb ‘ 1lb = 453.6 g 1 amu = 1.6605 x 10'27 kg ' 1 02 (ounce) = 28.35 g 0 Volume ' 1 L = 1000 mL= 1.06 qt ' 1 ft3 = 28.32 L 1 mL = 1 cm3 = 0.03381 02 1 gal = 3.785412 L = 4 qt Pressure 1 atm = 760. mmHg 1 torr = 1 mmHg 1 atm = 14.6959 lb/ln2 (psi) 1 atm = 101,325 Pa 1 Pa = 1 N/m2 ,. 1 bar = 100 kPa , Energy ' * 1 eV = 1.1602 x 10491 1 cal = 4.184J (exact) Force 1 N = 0.22481 lb Compound Units: Newton'(N): IN '= 1kg.m/s2 JoulcU): U = 1N.m = l<g.m2/s2 Metric prefixes: ki|o(k)=103 ’mega(M)‘=106 giga(G)=109 tera(T)=1012 peta(P)=1015 centi (c) = 10'2 micro (u) = 10'6 nano (n) = 10'9 pico (p) = 10'12 femto (f) = 10'15 Physical Constants: mass of electron 0.000549 amu mass of proton ' 1.00728 amu mass of neutron 1.00867 amu Avogadro’s Number (NA) 6.0221367 x 1023 speed of light 2.99792 x 108 m/s acceleration due to gravity 9.80665 m/s2 4of4 ...
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Worksheet 1 Key - Chem 142, Winter 2012 Name Group Activity...

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