Metrics, Significant Figures, Conversions, and Density

Metrics, Significant Figures, Conversions, and Density Review! YEAH!

How Many Significant Figures Do I Have? • 0.0101010100 • 9 • 300 • 1 • 300. • 3 • 3.12050 • 6 • 4.05 • 3 • 0.0020 • 2

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 density is 2.45 g/cm3, what is the volume of the object? • 124.589/2.45 = 50.9 cm3

Question 7 • 30,833 mg = ____ kg • Move 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 is 1.56 g/cm3. 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 days = _______ s • 1.25 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 x W x H

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 km2 = _____ m2 • Normally 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 cm3 = _____ m3 • Normally 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 = ______ K • °C = 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 105 in decimal notation? • 486,900

Question Twenty Four • What is 5.21 x 10-4 in decimal notation? • 0.000521

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 cm3 = ____ in3 • 15.869 cm x 1/2.54 x 1/2.54 x 1/2.54 = 0.96839 in3

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 108mg. 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 107 nm to cm. • Nano to centi is seven to the left • 6.5 cm

Question Thirty Five • 87 mm2 = ____ dm2 • mm 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, using proper sig figs • 5.0385 + 8.9 + 14.203 = • 28.1

Question Thirty Seven • The density of an object is 5.46 g/cm3. 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!!

Metrics, Significant Figures, Conversions, and Density