Circle your lab section

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1 Homework 1 Circle your lab section Name TTh 8:00 MW 11:15 MW 2:30 Directions: Work out all problems on separate sheet(s) of paper and attach this page. To receive full credit you must show all work and box your answers. For problems containing tables, you can fill in the tables on this sheet. Please use the periodic table provided on our course website for any problems requiring the use of a periodic table. 1. Below are fragments of two different rulers (units are centimeters) used to measure distance. A student reported the length of a cylinder of gold to be cm. Which ruler was used by the student? Ruler 1 Ruler 2 2. Answer the following questions using the diagram below. Units are in centimeters. a. Determine the length of arrow A. Assume arrow begins at the zero point of ruler. b. Determine the length of arrow B. Assume arrow begins at the zero point of ruler. B A Answer the following questions using the diagram below. Units are in centimeters a. Determine the length of arrow C. Assume arrow begins at the zero point of ruler. b. Determine the length of arrow D. Assume arrow begins at the zero point of ruler. D C 10 20

2 4. Using information gathered from the previous two problems, calculate the combine length of objects A, B, C, and D. 5. Below is a ruler containing only tick marks every ten centimeters. Write the correct measurement in the appropriate box Convert the following temperatures from Celsius into Fahrenheit. a. 1.3 F b. 5.7 F c. 9.6 F d F 7. The temperature of an object is determined to be F. a. What is the temperature of this object in Celsius? b. What is the temperature of this object in Kelvin? 8. The temperature of an object is determined to be C. a. What is the temperature of this object in Fahrenheit? b. What is the temperature of this object in Kelvin? 9. An object s length was determined to be inches. What is the length of the object in centimeters? 10. Below is a diagram of a box with dimensions provided. a. Report the volume of the box using cubic centimeters. b. Report the volume of the box in milliliters. c. Report the volume of the box using cubic inches cm 4.00 cm cm 11. A cyclist is travelling miles/hour. What is the cyclist s speed in feet/second?

3 12. How many significant figures are in each of the following numbers? Write your answer on the line provided. a b c d e x Round the following numbers to 2 significant figures. You may need to use scientific notation. Write your answer on the line provided. a b c d e A student was asked to determine the density of an unknown piece of metal. The student decided to use water displacement as a strategy. These are the steps the student took. First: Determined the mass of the empty graduated cylinder, g Second: Placed 42.0 ml (density = 1.00 g/ml) of water into the cylinder. Third: Placed the metal into graduated cylinder. Fourth: Determined the final volume of water + metal, 69.2 ml. Fifth: Determined the mass of cylinder with all its contents, g What is the density of the metal? 15. The accepted value for the density of a US penny produced in 1992 is g/ml. Two students were asked to determine the density of 10 pennies from The results are shown below. Which student was the most precise? Which student was most accurate? Student 1 Student 2 Density (g/ml) Density (g/ml) Density (g/ml) Density (g/ml)

4 16. In 1982 US mints changed the composition of the penny to be 97.5% zinc and 2.5% copper. Prior to 1982 a penny was 95% copper and 5% zinc. The density of a penny from 1970 is 8.8 g/ml. Using information from the previous problem determine which metal, zinc or copper has a higher density. 17. California has been experiencing a serious drought for many years. Many households are trying to save water using a variety of techniques. In many homes, flushing the toilet is responsible for the largest amount of water usage. According to the World Toilet Organization (I m not making this up, the average person flushes the toilet 7 times a day. Placing a brick into the reservoir tank of a toilet reduces the amount of water required to fill the tank. A typical brick has a volume of 1430 cm 3. a. How many gallons of water can be saved each day in a household consisting of 4 average people by placing a brick in the reservoir tank? (1 gallon = L) b. What other techniques can be used around the house to save water? List three well thought out examples. 18. Solve for x in the following equations. Report your answer with the proper number of significant figures. a. x = 23.4 m s +! m $ # 2 " s % &! $ # " s & % b. c. d. e. f. x = 2.45 in in in in in x = x = (103.5)(0.0001) x = x = (65.56 cm)(1801 cm) + (9323 cm cm 2 ) cm 2 g. x = cm cm cm x 100% 19. Calculate the volume (in ml) of grams of an object with a density of 1.73 g/ml.

5 20. On the course website is a periodic table with elements to become familiar with. To get started, complete the following table. Elemental Symbol Elemental Name C Calcium Cl Sodium Zn Silver Au Copper 21. Below is a graph produced in lab by a student trying to determine the rate of evaporation of water from an Erlenmeyer flask. The mass measurements represent the mass of the flask with water. The equation of the line is y = x Answer the following questions about this experiment. a. How long (in minutes) will it take for 15.0 gams of water to evaporate? b. What is the rate of evaporation in kilograms/hour? Mass (g) Determining the Rate of Evaporation of Water from an Erlenmeyer Flask Time (min)