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Homework 2 Due: Monday, August 22nd, 2011
Conversions and Scientific Method
Instructions: FIRST: Read (Analyzing Data) Chapter 2 Sections: 1 and 2... It may not be the same Chapter in your book, but look for the Analyzing Data Chapter. SECOND: Carefully analyze the conversions below, follow each step to make sure it has been done correctly. If you find an error make corrections (Circle the error. Then do the problem again showing all of your work, steps followed and units, with the correction and the right answer). THIRD: Do the conversions showing all of your work: steps followed, units, formulas and conversions! FOURTH: Define Avogadro’s number and what it’s used for. ***All you have to turn in are the corrections and the THIRD and FOURTH instructions. ***Showing your work is part of your grade and you will get credit for it!!!! ***There is a conversion chart attached at the end of the document for you to use. Problems: 1. 12 feet to centimeters 1 meter = 39.307 inches 1 foot = 12 inches 12 feet x 12 inches x 1 meter 100 cm = 366.35 centimeters 1 foot 39.307 inches 1 meter 2. 1Gm to mm 1 Gigameter = 109 meters 1 meter = 1000 millimeters 1 Gm x 109 meters x 1 meter 1000000 millimeters 1 Gm 1000 millimeters 3. 450 Celsius to Kelvin oC = K -‐ 273 à first solve for K
I) K = oC + 273 II) K = 450 + 273 III) K = 723 K
4. 278 K to F OC = K + 273
Homework 2 Due: Monday, August 22nd, 2011 F = 1.8C + 32 There are two ways to solve this problem.
I) C = 278 + 273 = 551O C II) F = 1.8 (551) + 32 III) F = 1023.8 OF
OR – using substitution
I) F = 1.8 (K + 273) +32 II) F = 1.8 (278 + 273) + 31 III) F = 1023.8 OF
5. What is the volume of a substance that has a mass of 34.5 grams and a density of 3.45 g/m3 in in3 D = mass/volume
I) Solve for volume: v = m/D II) V = (34.5 g) / (3.45 g/ m3) III) V = 10 m3 IV) Now convert from m3 to in3
1 meter = 39.307 inches 10 m3 x 39.307 in = 393.07 in3 1 m 6. What is the mass, in slugs, of an object that applies a pressure of 600 Pa on a table that is 2 decimeters by 2 decimeters? P = mass x acceleration/ area
I) First write down the information you have: i. P = 600 Pa ii. Acceleration: 9.8m/s2 iii. Are = length x length = 2 decimeters x 2 decimeters = 4 dm2
1. You have to convert from decimeters to meters because Pascals use meters NOT decimeters. Meters is the SI unit deci is the PREFIX. ( 1 meter = 10 decimeters)
4dm2 x 12meter = 0.04 m2 102decimeters
iv. Mass = ?
II) Then solve for mass using the formula for Pressure: i. Mass = P x area / acceleration
Homework 2 Due: Monday, August 22nd, 2011
ii. Mass = 600 Pa x 0.04m2/ 9.8m/s2 iii. Mass = 2.449 kilograms
III) Now convert from kilograms to slugs 1 kilogram = 0.0.685 slugs 2.449 kg x 0.0685 slugs = 0.1676 slugs 1 kg 7. Convert to scientific notation: 0.3050 Ans: 3.05 x 101 8. Convert to scientific notation: 234500000000 Ans: 2.345 x 1011 9. How many moles of Carbon are in 4.34x1023 atoms of Carbon? 1 mole = 6.023x1023 atoms (This is called Avogadro’s number: the number of molecules of atoms in a mole of matter) 4.34x1023 atoms of C x 1 mole = 0.723 moles of C 6.023x1023 atoms 11. How many atoms of Helium are in 2 moles of Helium? 1 mole = 6.023x1023 atoms (Avogadro’s number) 2 mol He x 6.023x1023 atoms He = 12.023x1023 atoms He 1 mol He Conversions: Please do the following conversions (Show all of your work: steps followed, units, conversions, formulas!)
1. What volume is occupied by 16.4 g of mercury in cm3? (The density of mercury is 13.6 g/mL).
2. What is the mass, in slugs, of an object that is applying a pressure, to another object, of 9.45x104 Pa? (Use gravitational acceleration = 9.8m/s2)
3. 55mL to in3 4. 90 g/cm3 to km3 5. Convert these two numbers to scientific notation:
a. 0.0000000056 b. 45682980.0