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Metrics, Significant Figures, Conversions, and Density Review! YEAH! How Many Significant Figures Do I Have? 3.12050 6 • 0.0101010100 •9 4.05 3 • 300 •1 0.0020 2 • 300. •3 Question Two 457 km = ________ cm Move decimal 5 to the right: 45,700,000 Question Three 14.6 yards = ____ ft 14.6 yds x 3ft/1yd = 43.8 ft Question Four Add, using correct significant figures 3.492 + 0.303 + 30.30 34.10 Question Five 37,854,120 mL = ______ L Move decimal 3 to the left, 37854.12 No zero because of sig figs Question 6 If the mass of an object is 124.589 grams and the 3 density is 2.45 g/cm , what is the volume of the object? 124.589/2.45 = 50.9 3 cm Question 7 30,833 Move mg = ____ kg decimal six to the left 0.030833 kg Question Eight 5 mL = _____ mL Move decimal 3 to the left 0.005 mL Question Nine The density of an object 3 is 1.56 g/cm . What is the mass of this object when the volume is 12 L? Convert 12L mL 1.56 x 12,000 = 19,000 g Question Ten 1.25 s 1.25 days = _______ days x 24 hours x 60 min x 60 sec = 108000 s Question Eleven If I am measuring with a ruler in centimeters, how many digits past the decimal should I record? 2 Question Twelve How do I find the volume of a rectangular solid? L xWxH Question Thirteen I took the mass of a block of wood. The mass was 198 mg. I then measured the block and it was 14 cm wide, 3 cm high, and 17 cm long. What is the density of the wood? Multiply L x W x H to get volume 0.198/714 = 0.0003 g/cm3 Question Fourteen 160 2 km Normally = _____ 2 m you would move three to the right, but since it’s squared you’d do that twice… so 6 to the right 1.6 x 108 m2 Question Fifteen 156 3 cm Normally = _____ 3 m you would move two to the left, but since it’s cubed, you do that three times, so move six to the left 1.56 x 10-4 m3 Question Sixteen One of the largest gold nuggets ever discovered was found in Australia in 1872. The nugget had a mass of 286 kg. Given that 19.32 g/cm3 is the density of gold, calculate the volume of this nugget Convert 286kg 286000 g 286000 / 19.32 = 14800 cm3 Question Seventeen I am measuring the length of a stirring rod and I get: 1.25 cm, 12.8 mm, and 0.129 m. The actual length of the stirring rod is 19.3 cm. Am I accurate? Am I precise? You are not accurate because you did not get the correct number. You are also not precise because all measurements are not close to each other when converted. Question Eighteen I am measuring the mass of sodium chloride for an experiment. I obtain a measurement of 12.236 mL. What is wrong with the way I have reported this value? Mass should be in units of grams, not milliliters Question Nineteen 48°C °F = _____°F = 9/5°C + 32 9/5*48+32 = 120°F Question Twenty 115°F °C = ______ K = 5/9(°F -32) 5/9(115-32) = 46.1°C K = °C + 273 46.1 + 273 = 319 K Question Twenty - One Express 125,000,000,000 in scientific notation 1.25 x 1011 Question Twenty Two Express 0.0000008 in scientific notation 8 x 10-7 Question Twenty Three What is 4.869 x decimal notation? 486,900 5 10 in Question Twenty Four What is 5.21 x in decimal notation? 0.000521 -4 10 Question Twenty Six 298 K = ____°F 298K-273 = 25°C 9/5(25)+32 = 77.0°F Question Twenty seven How many significant figures do I have? 12,000,000 2 Question Twenty Eight How many significant figures do I have? 10.0 3 Question Twenty Nine A sample has a volume of 12.5 L and a mass of 25.8 kg. What is its density in g/L? 25,800/12.5 = 2060 g/L Question Twenty Nine A student finds the density of carbon monoxide to be 1.62 g/cm3. The accepted value is 1.12 g/cm3. What is the percent error? |1.12-1.62| / 1.12 x 100 = 44.6% Question Thirty One inch = 2.54 cm 15.869 15.869 3 cm = ____ 3 in cm x 1/2.54 x 1/2.54 3 x 1/2.54 = 0.96839 in Question Thirty One If I am driving in a car at 65 miles/hour, what is my speed in meters/second 1 mile = 1.6 km 65 miles x 1.6 km/mile x 1000 m/km x 1hr/60min x 1min/60 sec = 29 m/s Question Thirty Two I am measuring the mass of calcium chloride for an experiment. I measure the mass three times, obtaining values of 125.46 g, 0.12455 kg, 124,999 mg. The actual mass is 1.25 x 108 mg. Am I accurate? Am I precise? You are both accurate and precise Question Thirty Three I measure the volume of a liquid to be 124.56 mL. The actual volume is 12.8 cL. What is my percent error? Convert to the same unit first! |12.8 – 12.456| / 12.8 x 100 = 2.69% Question Thirty Four Convert 6.5 x 7 10 nm to cm. Nano to centi is seven to the left 6.5 cm Question Thirty Five 87 2 mm mm = ____ 2 dm to dm is usually two steps to the left. Since it’s squared, you’ll move four spots to the left. 0.0087 Question Thirty Six Add, figs using proper sig 5.0385 28.1 + 8.9 + 14.203 = Question Thirty Seven The density of an object 3 is 5.46 g/cm . Calculate the volume, in liters, of an object that has a mass of 540 mg. 9.9 x 10-5 L Question Thirty Eight The mass of an object is 65 dg. The density of the object is 4.392 g/L. What is the volume of the object in mL? 1500 mL Don’t forget to study your equipment and reading equipment!!