Copy of Boyle’s and Avogadro’s Law Lab.docx

5. When data collection is complete, a graph of pressure vs . volume will be displayed. To examine the data pairs on the displayed graph, tap any data point. As you tap each data point, the pressure and volume values are displayed to the right of the graph. Record the pressure and volume data values in your data table. 6. Based on the graph of pressure vs . volume, decide what kind of mathematical relationship exists between these two variables, direct or inverse. To see if you made the right choice: a. Choose Curve Fit from the Analyze menu. b. Select Power as the Fit Equation. The curve fit statistics for these two data columns are displayed for the equation in the form y = Ax ^ B where x is volume, y is pressure, A is a proportionality constant, and B is the exponent of x (volume) in this equation. Note : The relationship between pressure and volume can be determined from the value and sign of the exponent, B . c. If you have correctly determined the mathematical relationship, the regression line should very nearly fit the points on the graph (that is, pass through or near the plotted points). d. Select OK. 7. (optional) If directed by your instructor, proceed directly to the Extension that follows Processing the Data. DATA AND CALCULATIONS This table is meant to give you room to record your constants for all levels. Volume (mL) Pressure (kPa) Constant, k (P / V or P • V) 5.8 158.726302528 920 10.8 91.7098722879 990 13.3 70.0193834752 931 15.8 62.3894443403 985 18.3 56.1600369493 1027.728 20.8 49.5479490537 1036.8176 Chemistry with Vernier 3

The constant values were somewhat varied in the first chart, but they had less variation in the second. 4. Using P , V , and k , write an equation representing Boyle’s law. Write a verbal statement that correctly expresses Boyle’s law. Boyle’s law says that as volume increases, pressure decreases when the amount of air stays the same. 5. For the pressure and volume part of this lab, what experimental factors are assumed to be constant during the experiment? The temperature of the air, the pressure of the air in the room. 6. Which of the relationships are true n x P = k or n/P = k? n * P = k 7. Using n, P, and k, write an equation representing the relationship between pressure and moles. n * P = k 8. If you have 10.0 mls of air in the syringe, how many moles of air do you have in the syringe? 10.0 mL / P E XTENSION Q UESTIONS 1. To confirm that an inverse relationship exists between pressure and volume, a graph of pressure vs . reciprocal of volume (1/volume) may also be plotted. To do this, it is necessary to create a new column of data, reciprocal of volume, based on your original volume data: a. Tap the Table tab to display the data table. b. Choose New Calculated Column from the Table menu. c. Enter the Name (1/Volume) and Units (1/mL). Select the equation, A/X. Use Volume as the Column for X, and 1 as the value for A. Select OK. 2. Follow this procedure to calculate regression statistics and to plot a best-fit regression line on your graph of pressure vs . 1/volume: a. Choose Graph Options from the Graph menu. b. Select Autoscale from 0 and select OK. c. Choose Curve Fit from the Analyze menu. 6 Chemistry with Vernier