Chemistry Lab Mr. Zamojski Q1 Mass & Volume PRE-LAB ASSIGNMENT

Transcription

1 Name: Date: Chemistry Lab Mr. Zamojski Q1 Mass & Volume PRE-LAB ASSIGNMENT Required Safety Data Sheets (SDS): 1) Copper 2) Tin These 2 safety data sheets (SDS) are attached at the end of this pre-lab assignment. You can also refer to the Flinn Scientific SDS database ( Required Pre-Lab Video: ZamJ713 channel on YouTube: Quarter 1 Chemistry Lab Mass & Volume QUESTIONS: Refer to the information from the pre-lab video and the SDS to answer the questions below. Defining Mass & Volume 1) Mass is how much is in matter. Volume is how much that matter takes up. Doing the Lab Refer to the SDS for Copper. 2) Refer to section 2. Are there any hazards associated with this substance? 3) Refer to section 8. What should you do after handling this substance? Refer to the SDS for Tin. 4) Refer to section 2. Are there any hazards associated with this substance? 5) Refer to section 8. What should you do after handling this substance? 6) What safety equipment is essential for this lab? Measurements for Copper 7) In the graduated cylinder where should you read the water line to determine the volume of water? 8) What equation should you use to calculate the volume of copper? Volume of Cu = - 1

2 Measurements for Tin 9) What is one way you can retrieve the metal bars from the graduated cylinder? 10) What equation should you use to calculate the volume of tin? Volume of Sn = - After Completing All Copper & Tin Measurements 11) How should you label the horizontal axis (x-axis)? 12) How should you label the vertical axis (y-axis)? 13) Since you are plotting your Cu and Sn data on the same graph, how can you make sure you can tell which data points belong to each metal? 2

3 Name: Date: Partner(s): Chemistry Lab Mr. Zamojski Q1 Mass & Volume LAB PROCEDURE Purpose: We have practiced using the appropriate tools to measure mass (amount of stuff) and volume (amount of space). Now we will perform measurements to determine if there is a relationship between an object s mass and its volume. Mass Measurement Volume Units Used Tool Used to Make Measurement Drawing of That Tool We will perform 5 mass and volume measurements of each of two metals, copper (Cu) and tin (Sn), and compile the results to determine if there is relationship between the mass and volume of copper and between the mass and volume of tin. At the conclusion of this lab you will be able to explain the relationship between the mass and volume of matter. LAB GRADE Your grade for this lab will be based on the following criteria: Using the proper safety equipment (goggles) Following procedures and staying on task at your lab station Following safe practices and properly handling accidents Cleaning up your lab station Completing the lab report 3

4 Materials: 1) goggles 2) copper bars 3) tin bars 4) digital scale 5) graduated cylinder 6) water Measuring Mass & Volume Procedure: 1) Put on your goggles. 2) Measure the mass of any amount of copper. 3) Measure the volume of that amount of copper using volume displacement. Volume displacement is a procedure used to determine the volume of solid objects that cannot be easily measured with a ruler. Refer to the procedure below to determine volume by displacement. 4) Fill your graduated cylinder with enough water so that the object you are measuring will be completely submerged. a. Do not fill the graduated cylinder above the calibrations or you will not be able to take the second volume reading needed. 5) Before putting your object in the graduated cylinder, record the initial volume in the graduated cylinder by reading the meniscus at eye level. 6) Carefully put the object into the graduated cylinder. b. If the object is not fully submerged, take the object out and repeat steps 3 & 4. 7) The water level in the graduated cylinder will rise. Record the final volume in the graduated cylinder by reading the meniscus at eye level. 8) The volume of the object is the difference between the final volume and the initial volume. Volume of Object = Final Volume Initial Volume 9) Repeat steps 1-7 for a total of 5 trials for copper. 10) Repeat steps 1-8 for tin. Clean Up: A) Pour water from your graduated cylinder into the sink. Stick your graduated cylinder on the drying rack near the sink. B) Dry off any metal bars that are wet and return them to your instructor. C) Turn off your electronic scale, put its lid on, and give the scale to your instructor. D) Return your goggles to the goggles cabinet. 4

5 Mass (g) Mass (g) ANALYSIS Materials: 1) graph paper 2) ruler Make a scatterplot of your mass and volume data for both copper and tin. Make sure to include the following: 1) A Title Mass & Volume Data for My Name Mass & Volume Data for 2) Graph your volume data on the x-axis (horizontal axis) and your mass data on the y-axis (vertical axis) 3) Use an appropriate scale for your mass and volume data 4) Label your horizontal axis Volume (ml) 5) Label your vertical axis Mass (g) 0 0 Volume (ml) 6) Use different marks to distinguish between your tin data and your copper data. For example, tin data could be represented by filled in circles ( ) and copper data could be represented by open circles (o). Make a key on your graph paper to explicitly state how you labeled your data points. 7) Using a ruler draw a best-fit line for your tin data and for your copper data. A best-fit line should try to include or be as close as possible to all of your data points. For these sets of data have your best-fit line intersect with the origin (0,0) Mass & Volume Data for Volume (ml) 5

6 8) Calculate the slope for both of your best-fit lines. Show your work in the space below, and be sure to include UNITS! slope = y x = (mass of metal) (volume of metal) = y 2 y 1 x 2 x 1 Sample Calculation: slope = y x = y 2 y 1 45 g 23 g 22 g = = = 7.3 g/ml x 2 x ml 3.0 ml 3.0 ml Slope calculation for Cu best-fit line. Slope calculation for Sn best-fit line. 6

7 Name: Date: Chemistry Lab Mr. Zamojski Q1 Mass & Volume DATA TABLE 1 Mass of Cu (g) Initial Volume (ml) Final Volume (ml) Volume of Cu (ml) Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Mass of Sn (g) Initial Volume (ml) Final Volume (ml) Volume of Sn (ml) Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 7

8 Chemistry Laboratory Write-up Checklist Experiment: Volume and Mass Safety, 1. Used goggles Procedures, & Cleanup (2 points) Purpose and Design (2 points) Data & Evaluation (6 points) Your lab write-up is due by FRIDAY, NOVEMBER 3, Name 2. Followed procedures and stayed on task 3. Followed safe practices 4. Cleaned up lab station prior to leaving 1. What were you trying to learn in this lab? 2. Briefly describe the procedure you used. Include the following 1. Completed Data Tables for Cu & Sn 2. Scatterplot of your data on graph paper 3. Best-fit lines for each data set 4. Calculations of slopes of best-fit lines. Conclusion (7 points) Applications (8 points) 1. What is the relationship between mass and volume for each data set? 2. What is the meaning of the slope? 3. Why are there two separate lines? 4. State the term used for the relationship between mass and volume of an object and explain in your own words what that term means in one sentence. 5. Percent error calculation of copper density. 6. Percent error calculation of tin desnity. 7. Discussion of accuracy of results. 1. Complete questions from Unit 1, Worksheet 3 Mass, Volume, and Density Maximum Score = 25 points Your score 8

9 Name: Lab: Mass & Volume PURPOSE: In this lab we performed measurements to determine the relationship between _. EXPERIMENTAL DESIGN: In this experiment we took measurements on two different metals, and. To measure the mass we used a. To measure the volume we used a and used a technique called. We completed trials for each metal. DATA & EVALUATION: *** Attach DATA TABLE 1 & your scatterplot on graph paper CONCLUSIONS: 1) Relationship between mass and volume for each metal a. The relationship between mass and volume for copper is g/ml. b. The relationship between mass and volume for tin is g/ml. 2) The significance of these slopes is 3) The reason there are two separate lines (one for tin and one for copper) 9

10 4) The term used for the relationship between mass and volume is. In my own words this term means: 5) Percent Error is a calculation used to determine how accurate the results of your experiment are by comparing the measurements or values you obtained to the accepted measurement or value. The following equation is used. Percent Error = Measured Value Accepted Value Accepted Value 100% When using the percent error equation, do not be concerned if you get a negative number. This is acceptable. If your percent error is positive, this means that your measured value is greater than the accepted value. If your percent error is negative, this means that your measured value is less than the accepted value. a. Refer to your SDS for Copper. In Section 9 Physical and Chemical Properties, the specific gravity, which is another word for density, is stated. What is the specific gravity of copper? g/ml Using the equation above calculate the percent error for the density of copper. * Your measured density is the value of the slope of your best-fit line for your copper data. * The answer you just wrote for 5a is the accepted value for the density of copper. Show Your Work Here: Percent Error for Density of Copper = b. Refer to your SDS for Tin. In Section 9 Physical and Chemical Properties, the specific gravity, which is another word for density, is stated. What is the specific gravity of tin? g/ml 10

11 Using the equation above calculate the percent error for the density of tin. * Your measured density is the value of the slope of your best-fit line for your tin data. * The answer you just wrote for 5b is the accepted value for the density of tin. Show Your Work Here: Percent Error for Density of Tin = If a percent error is within 10% ( 10% < percent error < 10%), the results are considered reasonably accurate. o This is acceptable accuracy for a high school chemistry lab. If your percent error is greater than 10% or less than 10%, then the results are not considered accurate. At this point you need to determine what your sources of error and whether the errors are personal (lack of care and precision in completing measurements) or systematic (the measuring tools are not precise enough or there is something wrong with the procedure used). c. Based on the calculations you have completed are your measured densities of copper and tin reasonably accurate? d. If they are reasonably accurate explain what you did during the experiment ensure good results. If they are not reasonably accurate, propose sources of error, either personal or systematic, that you think contributed to the less accurate results. 11

12 Name Date Chemistry Unit 1 Worksheet 3 Mass, Volume, and Density 1. Study the matter shown in Figure 1. Each dot represents a particle of matter. [Assume the particles are uniformly distributed throughout each object, and particles of the same size have the same mass.] a. In the table below, show how the masses, volumes, and densities of A and B compare by adding the symbol <, >, or = to the statement in the second column. b. Explain your reasoning for each answer in the last column. Figure 1 FIGURE 1 A Property Relationship Reasoning A B B Mass A B Volume A B Density A B 2. Study the matter in Figure 2. [Assume the particles are uniformly distributed throughout each object, and particles of the same size have the same mass.] a. In the table below show how the masses, volumes, and densities compare by adding the symbol <, >, or = to the statement in the second column. b. Explain your reasoning for each..answer in the last column. Property Relationship Reasoning Mass A B Volume Density A C A B A C A B A C FIGURE 2 A C B 12

13 3. Is object E or object F more dense? [Assume the particles are uniformly distributed throughout each object, and particles with a larger size have a larger mass.] Explain your reasoning. FIGURE 3 E F 4. In Figure 4 below, a graph shows the relationship between mass and volume for two substances, A and B. Use the graph to answer questions about these two substances. a) Find the slope of the line for both A and B using correct units. State the physical meaning of the slope for each substance. b) You put 50.0 ml of A on a scale to measure its mass. What mass would the scale read? Explain your reasoning. c) You put 50.0 ml of B on a scale to measure its mass. What mass would the scale read? Explain your reasoning. d) Water has a density of 1.00 g/ml. Sketch the line representing water on the graph in Figure 4. e) Determine whether substance A and B will sink or float when placed in a bucket of water. A: sink float B: sink float (circle correct response) Defend your answer using the m-v graph, and your outstanding understanding of density. 13

14 5. Alicia s cheapskate boyfriend gave her a ring he claims is 24 carat gold. Alicia is skeptical. After chem class the next day she measures the mass of the ring, finds the volume of the ring by water displacement, and then calculates the density of the ring. Should she treasure the ring as his first truly generous gift to her, or throw it at him the next time he walks by? Defend your answer. DATA: Density of Gold: Mass: Final volume: Initial volume: Volume of ring: Density of ring: g/ml g 43.7 ml 42.2 ml 6. A student filled a graduated cylinder with water and read the meniscus at 25.8 ml. The student then dropped a solid material into the graduated cylinder and the water level rose to 35.9 ml. If the solid material had a density of 2.99 g/ml, determine the mass of the solid object. 14