J. Muench CHEM 120 Name:______________________ WORKSHEET #1 Due: _______________________ For all problems requiring calculations, please show work for FULL credit. Remember to round your answer to the correct number of significant digits. 1. Convert the following numbers either to scientific notation. a. 0.000032 b. 130,000 2. Perform the following calculation and report your answer in scientific notation. a. (8.4 x 104) (5.0 x 105) = b. (3.2 x 10-3) (4.0 x 103) = 3. Decide whether each of the following is an exact number or a measured number. a. there are 1000g in 1kg b. a patient’s cholesterol is 184 mg/dL c. a class has 33 students d. a student obtains 50.0 mL of water in a graduated cylinder 4. How many significant figures are in each of the following measured quantities? a. 10.00 mg b. 0.405 L c. 0.000790 m d. 893,000 km e. 12.50 mL f. 0.0023 g 5. Round the following calculations off to the correct number of significant figures. a. 21.49 0.00170 = b. 458 0.0052 = c. 118.535 116.825 = d. (125.05 123.35) 0.1460 = e. 35.05 42.0 0.0485 = f. (87.25 86.55) 1.67 =J. Muench 6. Convert each of the following using conversion factors. Remember to round your answer to the correct number of significant digits. a. 0.0035 m = ? mm b. 42,000 mL = ? L c. 2.5 quarts = ? mL d. 445 ft = ? m e. 5.5 lbs = ? g f. 1.50 yd = ? cm 7. During a workout on a treadmill, you average 5.5 miles per hour. a. What is this speed in meters per second? b. How long will it take for you to complete a 5.0 km "race" at this pace?J. Muench 8. A certain medication has a dosage of 5.00 mg per kilogram of body mass. What dose should a 120 pound female receive? 9. Find the unknown mass, volume, or density in each problem. a. An object has a mass of 28.50 grams and occupies 4.8mL. b. Zinc metal has a density of 7.14 g/mL. What volume of this metal would be present for a mass 35.5g? c. Aluminum metal has a density of 2.70 g/mL. What mass of this metal would be present for a volume of 55mL? Mixed Unit Problems 10. An 1885 Morgan Silver dollar had a mass of 0.942 ounces. If silver metal has a density of 10.5 g/mL, then what is the volume of a Morgan Silver dollar? 11. A Gold bar has dimensions of 12.0in x 4.0in x 3.0in. If the density of Gold is 19.3 g/cm3, then what is the mass of this