APPLIED CHEMISTRY, MS. WACK SCIENTIFIC MEASUREMENTS, HOMEWORK PACKET DAY 1 9/14/11 2 3 4 5 6 7 8 9 10 11 12 13 CLASSWORK Define Vocabulary Terms HOMEWORK Study for tomorrow’s vocabulary quiz Vocabulary Quiz (20 Points) Scientific Method/Parts of an Experiment HW1: Worksheet A Scientific Method Begin to Design Experiment: “Bubbles” Bubbles Lab (30 Points) Daily Quiz Uncertainty in Measurements Accuracy/Precision Percent Error Measuring Activity (5 points) Daily Quiz Significant Figures Daily Quiz Scientific Notation Daily Quiz Base & Derived Units Density Temperature Daily Quiz Dimensional Analysis All Homework and Extra Credit Due (50 Points) Finish Daily Quiz (25 Points) Density Pre-Lab Density Lab HW2: Worksheet B Complete the design of your bubbles lab. Finish Bubbles Lab HW3: Worksheet C Density Lab Complete Lab Study for Test Density Lab Due (40 Points) HW4: Worksheet D HW5: Worksheet E HW6: Worksheet F HW7: Worksheet G Finish Density Pre-Lab Work on Lab Review for Test 14 Tent. 10/4 Scientific Measurements Test (100 Points) TOTAL POSSIBLE POINTS FOR CHAPTER 1: 270 + 20 POSSIBLE EXTRA CREDIT POINTS HOMEWORK GRADES A 50/50 B 45/50 C 40/50 D 35/50 F 30/50 NO GRADE 0/50 ALL HW COMPLETE 7/7 HW 6/7 HW COMPLETE 5/7 HW COMPLETE 4/7 HW COMPLETE 3/7 HW COMPLETE LESS THAN 3/7 HW COMPLETE EXTRA CREDIT 6 Points: Ask Ms. Wack for the Article “Chefs as Chemists”. Answer the following questions about the article: 1) What are 2 hypotheses that may have been formed to lead to these chefs discoveries? 2) What is one experiment that may have been performed to lead to the chefs discoveries? -What would be the dependent and the independent variables in this experiment? -What would be the constant in this experiment? -What would be the control in this experiment? 3) What were two conclusions the chefs made? 5 Points: Worksheet I 4 Points: Worksheet J 5 Points: Worksheet K WORKSHEET A CHEMISTRY & THE SCIENTIFIC METHOD A. Classify each step in the following application of the scientific method as an OBSERVATION, HYPOTHESIS, EXPERIMENT, or THEORY. 1. An iron ball falls to Earth when you drop it. ________________________________________________________ 2. Earth is a giant magnet. ________________________________________________________ 3. An iron ball and a piece of wood are dropped at the same time from the same height._____________________________________ 4. The iron ball and wood fall at the same rate. ________________________________________________________ 5. The large mass of Earth causes it to exert the same gravitational attraction on any object, regardless of the object’s composition. ________________________________________________________ B. Propose one hypothesis for each of the following observations. 1. Hummingbirds have long beaks. __________________________________________________________________________________________________ 2. Moisture forms on the outside of a cold glass. __________________________________________________________________________________________________ 3. Ice cubes float. __________________________________________________________________________________________________ 4. There are fewer fish in the creek this year. __________________________________________________________________________________________________ C. For the following experiments identify the independent variable, the dependent variable, the control and the constant(s). 1. You water 3 sunflower plants with salt water. Each plant receives a different concentration of salt solution. A fourth plant receives pure water. After a 2 week period, the height is measured. Independent Variable:____________________________ Dependent Variable:________________________ Control:_______________________________________ Constant(s):_______________________________ 2. Three redwood trees are kept at different humidity levels inside a greenhouse for 12 weeks. One tree is left outside in normal conditions. Height of the tree is measured once a week. Independent Variable:____________________________ Dependent Variable:________________________ Control:_______________________________________ Constant(s):_______________________________ 3. One tank of gold fish is fed the normal amount of food once a day, a second tank is fed twice a day, and a third tank four times a day during a six week study. The fish’s weight is recorded daily. Independent Variable:____________________________ Dependent Variable:________________________ Control:_______________________________________ Constant(s):_______________________________ 4. Different rose bushes are grown in a greenhouse for 2 months. The number of flowers on each bush is counted at the end of the experiment. Independent Variable:____________________________ Dependent Variable:________________________ WORKSHEET B SCIENTIFIC THEORY & EXPERIMENTS MULTIPLE CHOICE Write the letter of the correct answer on the line. _____ 1. A student wants to test the hypothesis that plants need soil to grow. What is the independent variable of the experiment? a. air temperature b. amount of water c. amount of light d. presence of soil _____ 2. What does an experiment test? a. a conclusion b. a hypothesis c. an observation d. a control _____ 3. Which of the following is an example of a scientific question? a. Does a slice of pizza have more fat than a serving of green beans? b. Does pizza taste better than green beans? c. Is pepperoni a better pizza topping than mushrooms? d. Are store brand green beans tastier than bran-name green beans? _____ 4. A student uses a balance to find the mass of a lizard. Which method or process is the student using? a. independent variable b. conclusion c. hypothesis d. gathering data _____ 5. Daniella records how much of a certain chemical dissolves in 100 grams of water at different temperatures. Her data are shown below. 0C/24 g 20C/36 g 40C/48 g 10C/30 g 30C/42 g 50C/54 g What kind of data has Daniella recorded? a. inference b. conclusion c. qualitative d. quantitative _____ 6. Which best describes a scientific law? a. a rule that uses experimental results and observations to describe a pattern in nature b. a scientific explanation of related observations that have been repeatedly tested and shown to be true over time c. a suggested answer to a scientific question d. a written account of the purpose of an investigation, the procedure followed and the results obtained _____ 7. The density of an object is calculated by dividing the mass of the object by its volume. Which tools can be used to find the density of a bar of silver? a. beaker and pipette b. pan balance and graduated beaker c. beaker and metric ruler d. triple-beam balance and metric ruler _____ 8. The graph shows the relationship between the volume of a gas and its temperature when pressure is held constant. Which of the following statements summarizes the data in the graph? a. As the temperature increases, the volume of the gas decreases due to an increase in the motion of gas particles b. As the temperature increases, the volume of the gas increases due to an increase in the motion of gas particles c. The volume of the gas is not affected by an increase in temperature d. The volume is affected by temperature only if the gas is hydrogen WORKSHEET C UNCERTAINTY IN MEASUREMENTS A B C 1. Which of the above dartboards represents precision? __________________________________ 2. Which of the above dartboards represents accuracy? __________________________________ 3. Which of the above dartboards does represents neither precision nor accuracy? ______________________________ 4. To the correct number of significant figures, what is the volume of the liquid in the graduated cylinder to the left? 5. To the correct number of significant figures, what is the length of the paper above the ruler to the left? 6. How many digits are estimated in a measurement? 7. Explain how a series of measurements can be precise without being accurate. 8. A student measures the boiling point of water to be 98C. What is his percent error? WORKSHEET D CALCULATING WITH SIGNIFICANT FIGURES A. Round the following to the number of significant figures indicated in parentheses. 1) 8060 (3) ___________________________ 4) 36.618 (3) __________________________________ 2) 599.99 (3) ___________________________ 5) 0.08654 (2) __________________________________ 3) 2365.6 (4) ___________________________ 6) 0.002345 (3) __________________________________ B. Perform the following operations expressing the answer in the correct number of significant figures and units. 1. 1.35 m x 2.467 m = ________________________________________________________________ 2. 1035 m2 42 m = ________________________________________________________________ 3. 12 cm x 0.031 cm x 7.969 cm = ________________________________________________________________ 4. 55.46 g 28.9 g = ________________________________________________________________ 5. 289 cg x ________________________________________________________________ 1g= 100 cg 6. 1.152 mm x 0.215 mm x 0.032 mm = ________________________________________________________________ 7. 5.23 m2 16.941 m = ________________________________________________________________ 8. 6.419 g x 3.912 g x 7.0518 g x 0.00013 g _______________________________________________________ C. Circle the correct answer. 1. Which of the following shows two significant figures? a. 123000 b. 300 c. 0.001 d. 2.0 x 10-12 e. 8.70 d. 4 e. 5 d. 126.000 e. 201.0 d. 17 e. 6.0 2. How many significant figures are shown in the number 4.03 x 105? a. 1 b. 2 c. 3 3. Which of the following numbers shows 4 significant figures? a. 1800 b. 75.010 c. 0.009 4. Which of the following numbers shows 1 significant figure? a. 60.0 b. 1.0 x 101 c. 700 WORKSHEET E SCIENTIFIC NOTATION A. Express the following measurements in scientific notation. 1. 453.32 ___________________________ 6. 1,000 ___________________________ 2. 0.0000421 ___________________________ 7. 0.00040 ___________________________ 3. 667000 ___________________________ 8. 0.01001 ___________________________ 4. 885326251 ___________________________ 9. 50 ___________________________ 5. 1,000,000. ___________________________ 10. 0.0008 ___________________________ B. Convert the following to standard notation. 1. 3.0 x 106 ___________________________ 4. 4.4 x 10-7 ___________________________ 2. 1.49 x 10-5 ___________________________ 5. 3.75 x 102 ___________________________ 6. 3.35 x 101 ___________________________ 3. 5.000102 x 103 ___________________________ C. Perform the following calculations using scientific notation. Make sure your answer has the correct number of significant figures. 1. (9.39 x 106) x (4.37 x 10-8) = 2. (5.12 x 103) (8.61 x 104) = 3. (3.1 x 102) x (1.2 x 102) = 4. (1.0 x 109) (2.5 x 10-3) = 5. (3.234 x 103) x 1 (5.0234 x 10-23) = WORKSHEET F SI UNITS/DENSITY A. Complete the Following Table Measurement Unit Tool Mass of a Rock Your Body Temperature Volume of a Plastic Block Length of Your Classroom How much water a tablespoon holds How long between blinks of your eye B. The table below gives the density of selected substances. Answer the following questions. Substance Density (g/mL) Water (at 4C) 1.000 Hydrogen 0.00090 Carbon Dioxide ? Gasoline 0.68 Copper 8.89 Silver 10.5 Mercury 13.595 Tungsten 19.3 1. Which of the substances listed in the table has the greatest density?_______________________________________________ 2. Which of the substances listed in the table has the lowest density?________________________________________________ 3. If you were given a milliliter of copper and a milliliter of silver, which would weigh more? Why?______________________________ ____________________________________________________________________________________________________ 4. Corks are used on fishing lines because they float. What can you say about the density of cork?____________________________ ____________________________________________________________________________________________________ 5. To complete the table, calculate the density for carbon dioxide if 250.0 mL of the gas has a mass of 0.4997 g.__________________ 6. Suppose that 10 mL of each of the three liquids in the table—water, gasoline and mercury—were all placed in a test tube. The liquids do not mix with one another. In the three layers that would be produced, which liquid would be on top, which in the middle and which on the bottom?____________________________ C. Complete the following temperature conversions. K = C + 273 C = K -273 a) Convert -200C to Kelvin b) Convert 355 K to Celsius c) Convert 183.66C to Kelvin d) Convert 100.23 Kelvin to Celsius e) Convert 123C to Kelvin f) Convert 355.0 K to Celsius WORKSHEET G DIMENSIONAL ANALYSIS/CONVERSIONS 1. How many L are there in 1000 mL? 2. Convert 83 cm into meters. 3. Convert 459 L into milliliters. 4. Express 1123 pg in nanograms. 5. Express 2.5 mm in micrometers. 6. Convert 1342 cs to seconds. 7. Which is the smaller mass, 285.0 cg or 23.78 dg? (Hint: Convert both to g first to compare.) 8. Calculate the number of kilometers there are in 105 meters. 9. An object has a mass of 89.00 grams. Express this mass in centigrams. 10. A very small object is found to have a length of 0.000344 meters. Express this length in micrometers. WORKSHEET I EXTRA CREDIT 1. The table below gives data on the number of gallons of water used in a condominium building and the amount of the monthly water bill during 2008. Create a line graph for the data (may use computer or do by hand). Water Use (Gallons) Water Bill ($) 17 200 105.32 4100 32.01 1000 18.74 1205 19.67 1100 19.17 400 16.17 9500 63.64 8202 56.75 1400 20.45 5225 40.97 810 17.65 600 17.03 2. Draw a best fit line into the graph. 3. If a water main broke during the month of February due to a deep freeze, and the water usage in the building totaled 11,200 gallons, what would the bill amount to? 4. The water company sends the association a bill for $200, how much water did the building use? Should you argue about the bill? WORKSHEET J—EXTRA CREDIT WRITE THE LETTER OF THE CORRECT ANSWER ON THE LINE. _____ 1. A sample of an element has a mass of 34.261 grams and a volume of 3.8 cubic centimeters. To which number of significant figures should the calculated density of the sample be expressed? (A) 5 (B) 3 (C) 2 (D) 4 _____ 2. Which quantity of heat is equal to 200. joules? (A) 20.0 kJ (B) 0.200 kJ (C) 2.00 kJ (D) 0.0200 kJ _____ 3. A large sample of solid calcium sulfate is crushed into smaller pieces for testing. Which two physical properties are the same for both the large sample and one of the smaller pieces? (A) mass and density (B) mass and volume (C) solubility and density (D) solubility and volume _____ 4. The table below shows mass and volume data for four samples of substances at 298 K and 1 atmosphere. Which two samples could consist of the same substance? Sample Mass (g) Volume (mL) A B C D (A) A and B 30 40 45 90 (B) B and C 60 50 90 120 (C) A and C (D) C and D _____ 5. A student intended to make a salt solution with a concentration of 10.0 grams of solute per liter of solution. When the student’s solution was analyzed, it was found to contain 8.90 grams of solute per liter of solution. What was the percent error in the concentration of the solution? (A) 1.10% (B) 11.0% (C) 8.90% (D) 18.9% _____ 6. A student calculates the density of an unknown solid. The mass is 10.04 grams, and the volume is 8.21 cubic centimeters. How many significant figures should appear in the final answer? (A) 1 (B) 3 (C) 2 (D) 4 _____ 7. Horses kept in stables sometimes chew on wood. This can lead to damage to the mouth and digestive system. The graph above shows the results of a study of a medication that prevents horses from chewing on wood. From the graph, what inference can be made about the effectiveness of the product? (A) Most horses like the medication. (B) The medication is most effective between Days 4 and 5. (C) Most horses will show improvement within 7 days. (D) The effects of the medication are long lasting. _____8. If a design flaw is discovered, what is the next logical step for the researcher? A. Make the design modification to solve the problem B. Scrap the project and start again C. Obtain more money to support continued research D. Create another prototype WORKSHEET K—EXTRA CREDIT 1. Explain the mathematical relationship represented by the graph above. 2. A student wants to test the hypothesis that plants need soil to grow. What is the independent variable of the experiment? Substance Density (g/cm3) Aluminum 2.7 Copper 8.9 Silver 10.5 Lead 11.3 3. You are given a sample of an unknown metal. You determine that the mass of the metal is 1050 g and its volume is 100 cm3. Based on the information provided in the table above, what is the unknown metal? 4. How much is 2.3456% of 1.23456 grams of sodium chloride? 5. The ability of birds to change direction during flight depends on movements of their wingtips. Which technological advance did observation of this phenomenon influence?