DIMENSIONAL ANALYSIS CHALLENGE - ANSWERS 1 Measurements and Calculations How Are Measurements and Calculations Important in the Science of Chemistry? DIRECTIONS: Solve the following problems as a group. You should show your work (where appropriate) and cancel all units. We will go over the answers to these problems as a class. It may be helpful to approach each problem with the following strategy: What are we being asked to do? What information are we given? How can we use this information to solve the problem? Does our answer make sense? 1. What units would appear in the answer to a calculation which uses the following sequence of conversion factors? quark passel 2 goober parsec speck 2 parsec speck x x x x goober speck passel quark 3 passel quark 2 2. Use your calculator to solve the following. Express your answer in correct scientific notation. 6.02x10 5.02x10 2.4x10 8.5x10 = 235577219.4 or 2.356x10 5.8x10 4.7x10 9.6x10 23 13 -9 -15 11 7 8 18 3. Using any/all of the following equivalence statements, convert 3 fizzles to frizzles. 4 swizzles = 7 twizzles 2 fizzles = 3 drizzles 4 twizzles = 1 sizzle 10 swizzles = 4 frizzles 2 drizzles = 6 sizzles 3 fizzles x 3 drizzles 6 sizzles 4 twizzles 4 swizzles 4 frizzles x x x x 12.34 frizzles 2 fizzles 2 drizzles 1sizzle 7 twizzles 10 swizzles 4. Using your knowledge of English and metric system units convert 20, 000 leagues to meters 1 league = 3 nautical miles 1 nautical mile = 6080 feet 20,000 leagues x 3 nautical miles 6080 feet 1yard 1meter x x x 111, 192, 392.1 meters 1league 1nautical mile 3 feet 1.0936 yards Or another way… 20, 000 leagues x 3 nautical miles 6080 feet 1mile 1.6093 km 1000 meters x x x x 111, 236, 363.6 meters 1league 1nautical mile 5, 280 feet 1mile 1km 5. How many millimeters would this be? To convert FROM meters TO millimeters…multiply by 1000…that’s a LOT of millimeters! 6. Express the quantity 452.23x105 in correct scientific notation: For this problem it may help to convert the “incorrect” form of scientific notation given in the problem to its “normal” decimal equivalent… 452.23x105 = 45, 223, 000 …then put it in proper scientific notation: 4.5223x107 7. If gasoline costs $3.98 per gallon, how much will it cost to fill up a gas tank that has a volume of 2.30x102 liters? This problem requires two steps…first change the 2.30x102 liters TO gallons: (You could also convert the $3.98 per gallon TO $ per liter) 2.30x10 2 liters x 1gallon 60.76 gallons 3.7854 liters -OR- 1gallon $3.98 $1.05 x gallon 3.7854 liters Liter Then, multiply by the cost of gasoline per gallon: (OR multiply the $/L by the size of the tank) $3.98 $1.05 -OR $241.82 x 2.30x10 2 Liters $241.50 gallon Liter NOTICE that we get (relatively speaking) the same answer either way…my difference is due to rounding numbers… 60.76 gallons x 8. Convert the speed of 65 miles per hour to m/sec…to km/day 65 miles 1.6093 km 1000m 1hour 1min x x x x 29.06 m sec hour 1mile 1km 60 min 60 sec 65 miles 1.6093 km 24 hours x x 2510.5 km day hour 1mile 1day 9. If your car gets 26 miles per gallon, how many meters could your car travel on 10 gallons of fuel? Similar to question 7…there are a few ways to solve this problem. One way would be to convert the 26 miles/gal to meters/gal then multiply by the amount of fuel (10 gallons): 26 miles 1.6093km 1000m x x 41, 841.8 meters gallon gallon 1mile 1km 41, 841.8 meters x 10 gallons 418, 418 meters gallon -ORWe could do the multiplying first to get a distance in miles that could be traveled with those 10 gallons of fuel…then convert miles to meters: 26 miles x 10 gallons 260 miles gallon 260 miles x 1.6093 km 1000 m x 418, 418 m 1mile 1km 10. If you work 40 hours per week and make $7.50 per hour, how many years will you have to work to make $1 million? 40 hours 52 weeks $7.50 $15, 600 …now we can use that answer like a conversion factor to answer x x 1week 1year 1hr year the questions that remains which is…if we make $15,600 per year and we want to make $1million…how many years will we have to work? 1year $ 1, 000, 000 x 64.1 years $15, 600