Safety Precautions Isopropyl alcohol is a moderate fire risk and slightly toxic by ingestion or inhalation. Wear chemical splash goggles. Rinse hands with water before leaving the laboratory. PROCEDURE Station 1: Measuring Length 1) Using a metric ruler, measure the length, width, and height of a textbook. 2) Record the measurements (in millimeters) in the data table in your notebook. Textbook Measurement Dimension Millimeters (mm) Centimeters (cm) Meters (m) Volume (cm3) Length Width Height Station 2: Measuring Volume Label your 2 small beakers: W (Water) and I (Isopropyl alcohol). Only labeled beakers will be given chemicals from the teacher. Part A – Direct Method 1) 2) 3) 4) Gather water from the sink into your W (water) beaker about ¾ of the way (not all the way full). Fill a test tube (carefully) with water from your W (water) beaker to the top. Pour the water into a 100-mL graduated cylinder. Record the volume of the water to the nearest milliliter in the Part A. Direct Method table. (Remember get to eye level – look at the bottom of the curve - the meniscus). Part A. Direct Method Milliliters (mL) Microliters (µL) Liters (L) Water Part B – Displacement Method 1) Fill the 100-mL graduated cylinder with water to the 50-mL mark. (Get water from the sink in your W (water) beaker if necessary.) 2) Record the initial volume of water (in milliliters) in the Part B. Displacement Method table. 3) Obtain a screw and carefully add the screw to the graduated cylinder. NOTE: To avoid cracking the graduated cylinder, tilt slightly sideways then add the screw. 4) Record the final volume of water (in milliliters) in the Part B. Displacement Method table. 5) Subtract the initial volume of the water from the final volume of water and record the amount of water displaced (the volume of the screw in milliliters) in the Part B. Displacement Method table. Part B. Displacement Method Initial Water Volume (mL) Final Water Volume (mL) Water Displaced (volume of screw) (mL) Station 3: Measuring Mass 1) Place Styrofoam cup on the balance. 2) Record the mass of the Styrofoam cup (in grams) in the Measuring Mass table. 3) At your lab table, measure 100 mL of water using a graduated cylinder (get more water from the sink if necessary with your W (water) beaker.) 4) Carefully pour all of the water from the graduated cylinder into the Styrofoam cup. 5) Record the mass of the water and cup in the Measuring Mass table. 6) Subtract the mass of the cup from the total mass and record the difference (mass of the water in grams) in the Measuring Mass table. Measuring Mass Mass of Cup (g) Mass of Cup and 100 mL of water (g) Mass of 100 mL of water (g) Station 4: Determining Density 1) Record the mass of the Styrofoam cup (in grams) in the Density Measurement table. 2) At your lab table, measure 20 mL of water using a 100-mL graduated cylinder (get more water from the sink if necessary with your W (water) beaker.) 3) Carefully pour the 20 mL of water into the Styrofoam cup. 4) Record the mass of the water and cup in the Density Measurement table. 5) Subtract the mass of the cup from the total mass and record the difference (mass of water in grams) in the Density Measurement table. 6) Discard the water (in the sink) and dry out cup (at lab table). 7) Take the W (water) beaker and request 20 mL of the sodium chloride (salt water) solution from your teacher. 8) Repeat steps 3 through 6 using 20 mL of salt water. 9) Take the I (Isopropyl alcohol) beaker and request 20 mL of the isopropyl alcohol solution from your teacher. 10) Repeat steps 3 through 5 using 20 mL of isopropyl alcohol. DO NOT POUR THE ISOPROPYL ALCOHOL DOWN THE SINK! 11) Record all measurements in the Density Measurement table. Density Measurement Substance Mass of Cup (g) Mass of Cup and Substance (g) Mass of Substance (g) Water Salt Water Isopropyl Alcohol Disposal: Consult your teacher for appropriate disposal procedures. Volume of Substance (mL) Density of Substance (g/mL) Analysis Post Lab Questions: Answer questions 1-3 in the Textbook Measurements table. Show your work and answer the remaining questions in your notebook. 1) Convert the data from Station 1 from millimeters (mm) to centimeters (cm) and meters (m). [ Use the following conversion factors: 10 mm = 1 cm & 1000 mm = 1 m ]. Record answers in the Station 1 Textbook Measurements table. 2) Convert the data from Station 2 from milliliters (mL) to microliters (µL) and liters (L). [ Use the following conversion factors: 1000 µL = 1 mL & 1000 mL = 1 L ]. Record answers in the Station 2 Part A. Direct Method table. 3) Convert the length measurements of the textbook in Station 1 to volume by multiplying length, width, and height. Record the answer in cubic centimeters (cm3). 4) Calculate the density of each liquid in Station 4 by dividing the mass (grams) by volume (mL). Record the values in the Station 4 Determining Density table. 5) At Station 3 the mass of 100-mL of water was determined. Using the data calculate the density of water. NOTE: Give your answer in g/mL. 6) How does the density of water calculated in Question 5 compare to the density value obtained at Station 4? 7) Which liquid at Station 4 has a greater density than water? Which liquid has a density less than water? Conclusion: In 3 paragraphs (approximately 5 sentences per paragraph) address the following prompts: 1) Summarize the lab procedures in your own words for the four Stations. 2) Discuss the results and address analysis from the post lab questions (focused on density – Questions 5,6,7) 3) Write about the skills and information that you learned from this experiment. Give details about any struggles or successes you exhibited. TEACHER Example: This is ONLY an idea to help you see the process. Please go into more detail regarding your team results. CONCLUSION MUST BE INDIVIDUAL! DO NOT copy the given example or a lab partner. Plagiarism is not worth it! In the Measurement in the Laboratory experiment there were four stations in which length, volume, mass, and density were determined. The different measurements were taken and calculated using tools such as a ruler, graduated cylinder, beaker, and balance (scale). The substances measured and compared were water from the sink, a salt water solution, and an isopropyl alcohol solution. Throughout the process of measuring and collecting data in the data tables, all safety rules and directions were followed. The density results from the experiment were exactly what I had expected. I noticed that the density of water calculated in Station 3 (1.00 g/mL) was very close in value to that of the density of water calculated in Station 4 (0.97 g/mL). Regardless of the volume or method used to obtain the density of a substance, the density of that substance should be the same. Density is a physical property of a substance so no matter how much you have of it the density is the same. My data showed that isopropyl alcohol had the smallest density (0.91 g/mL), water from the sink was in the middle (0.97 g/mL) and the salt water was the densest (0.98 g/mL). In this lab, I practiced how to be safe in the lab, learned how to read a graduated cylinder, and used data I collected to determine the density of various substances: sink water, a salt water solution, and isopropyl alcohol. I struggled with understanding all the directions at first, but as I concentrated on reading directions and asking my lab teammates questions I improved. I felt I was successful working with my team, converting the units like we have learned in class before, and following all the safety rules.