Boyle’s Law Lab Report

2/4/21 Boyle’s Law Lab Report Purpose: Using Boyle’s law, explore the relationship between pressure and the volume of a gas. Question: What is the effect of pressure on the volume of a gas? Hypothesis: If a pressure of a gas is increased, then its volume will decrease because the gas molecules will be pushed closer together. Variables: Because the volume depends on the pressure in this experiment, volume will be the dependent variable and pressure will be the independent variable. The constants will be temperature and the number of moles because throughout this lab those will remain the same. Materials: 60 mL syringe with cap, silicone lubricant, ring stand, ruler, burette clamp, book, balance, and four 1 kg weights. Procedure: ● Step 1: Gather Materials. ● Step 2: Measure the Area of the top of the Syringe. i. Using the ruler, measure the diameter of the top of the syringe. Divide the diameter by 2, then take the answer of that and square it. Then multiply that by π  . ● Step 3: Prepare the Syringe System. i. Take the cap off of the syringe and slide the plunger out from the top. To keep the experiment as accurate as possible, add a few drops of silicone lubricant into the syringe. Put the plunger back and make sure it is lined up with the 50 mL mark. Also put the cap back on. Then, move the syringe to the ring stand and use the burette clamp to secure it. ● Step 4: Measure the Mass of the Book. i. Make sure the balance is cleared, then measure the mass of the book to the nearest gram. Convert grams to kilograms to make it easier to find future values, then record it. ● Sub-Steps for Steps 5-9: i. Place the correct amount of weight on the syringe to apply additional pressure to the gas. ii. After the plunger has slid down, total the mass on the syringe record this value on the correct row of the data table. iii. Calculate the pressure using the formula, P = 1.03 (mass on syringe / area of top of syringe). iv. Measure the volume of the gas in the syringe and measure to the nearest 0.5 mL. v. Find the product of the pressure and the volume. Make sure to record all found values into the data table. ● Step 5: Measure Pressure and Volume with the Weight of the Book. ● Step 6: Measure Pressure and Volume with the Book and 1 kg of Weight. ● Step 7: Measure Pressure and Volume with the Book and 2 kg of Weight. ● Step 8: Measure Pressure and Volume with the Book and 3 kg of Weight. ● Step 9: Measure Pressure and Volume with the Book and 4 kg of Weight. Data: Circular Top of the Syringe Area (cm2 ) Diameter (cm) Radius (cm) 3.60 cm 10.2 cm2 1.80 cm Mass on Syringe (kg) Pressure (kg/cm2) Volume (mL) P•V 0 1.03 50.0 51.5 0.498 1.08 47.5 51.3 Book + 1kg of Weight 1.498 1.18 43.5 51.3 Book + 2kg of Weight 2.498 1.27 40.5 51.4 Book + 3kg of Weight 3.498 1.37 37.5 51.4 No Book or Weight Book Only Book + 4kg of Weight 4.498 1.47 35.0 51.5 Analysis: The collected data in the table shows how the experiment provided evidence that is in favor to Boyle’s law. Boyle’s law states that the product of P•V should be constant, which in the data it shows that the product in fact was constant, because it was all fairly close to 51.5. With the experimental results, the power regression equation for the relationship of volume and pressure is, V=51.4•P-0.999  . The constant, or k, of that equation is 51.4, which is fairly close to the atmospheric constant of 51.5. On a different note, the power of -0.999 is very close the power of -1. The power of -1 is seen again in the equation V=kP-1  , which is the inverse proportion between volume and pressure. This proves that the data collected is quite accurate, because also stated in Boyle’s law; the absolute pressure and the volume of a gas are inversely proportional. The reasoning for the accuracy of this experiment could have had to do with the correct amount of silicone lubricant being used in the syringe. The lab temperature changing or some air leaking out of the syringe could have caused any inaccuracy of this experiment. Conclusion: The hypothesis stated if a pressure of a gas is increased, then its volume will decrease because the gas molecules will be pushed closer together. This was correct because as the weight in the experiment was added to the top of the syringe, the volume of the air that had been trapped inside of it decreased. As more weight was added, the pressure increased, and the volume responded appropriately by decreasing, as it should have.