Title: Laboratory Techniques Lab #1 Chemistry Fall ‘12 Purposes: To acquaint us with techniques and tools used at the lab bench; to identify sources of error in procedures and improve upon them; and to perform error calculations based upon data recorded and calculated results. Record your observations, data, calculations and conclusions in an organized fashion in your lab book. Each section and task should be clearly identified in your notes. Portions labeled (CP) indicate that students wishing to earn CP credit for the course must complete these questions correctly. Everyone else must try them, too. Part 1: Graduated Measurements and Volume Calculations A) Use a ruler to determine the length, width and thickness of your lab notebook. Be sure to ESTIMATE THE FINAL DIGIT (OPBG). Record TWO measurements for each dimension: one in cm and one in mm. B) Calculate the surface area of the text book (L x W) in both cm2 and mm2. C) Calculate the volume of the text book (L x W x H) in both cm3 and mm3. D) (CP) Convert the volume of the lab book from cm3 to m3. Part 2: Thermometers A) Set up a ring stand with a ring clamp and wire mesh to boil 150 mL of tap water in a 250 mL beaker with a Bunsen burner. Have Mr. Williamson confirm the set up. B) Light and adjust your Bunsen Burner so it has a short (< 10 cm) blue flame with only a little yellow at the top. Have Mr. Williamson confirm your set up. C) Boil the water and record the temperature of boiling water. OPBG D) Calculate your absolute error and your percent error for the boiling point of water. The true boiling point of water is 100.0oC Absolute error = observed value – true value Percent error = absolute error x 100 True value E) What are some errors associated with your set-up? How can they be avoided in the future? F) What are some experimental errors that cannot be avoided? Part 3: Volumetric tools A) Take a 250 mL beaker and using the graduations on the side of the beaker do your best to measure 75 mL of tap water. Transfer the 75 mL of water to the 100 mL graduated cylinder and obtain a more accurate reading. ESTIMATE THE FINAL DIGIT for both measurements. B) Calculate the percent error of the beaker. Use the volume of 75 mL as the true reading and the volume in the graduated cylinder as the observed reading. Comment upon why there might be a difference. C) Mass an empty 100 mL beaker. Use the graduated delivery pipet and green pump to add 10.00mL of distilled water to the beaker. D) Mass the water and beaker. E) Compare the mass of the water to its volume. The density of distilled water at 25oC is 1.00 g/mL. Was your mass close to the volume of 10.00 mL? Discuss any differences. Part 4: Massing A) Zero the triple beam balance and have your teacher approve that it is zeroed. If the pan does not balance properly, spin the small knob at the base of the pan slightly in one direction or the other to adjust the balance. B) Determine the mass of your lab book. Record this mass on the inside front cover as well as in your lab work. Remember to go OPBG. Part 5: Graphing our Density of Aluminum A) Log-on to a desktop computer and click on the Start menu of your computer and open the Program file Vernier Software Graphical Analysis 3.1.1 B) You should see a data table on the left hand side and an x-y coordinate graph on the right side of the screen. Copy the class data into the proper data table. The x axis will be our volume and the y-axis will be the mass. (Giving you a slope of mass/volume which is density.) C) Click on Analyze in the menu, then on Linear Fit and the computer will generate a line of best fit for you with a slope of your line. The red line shows the data points connected in the order you entered them, the black line is the line of best fit. To print a graph – first change the alignment of the page by selecting Page SetUp under the File Menu and choosing “Landscape” rather than “Portrait”. D) Circle your three points on the graph. E) Identify any data that you question. Include a reason why you question them.