1. How do you handle the calculations and data for the gas law lab (molar mass of butane)? February 27

2. Finishing up the Gas Unit DataCalculations: Trial 1 Calculate pressure of gas sample: P T = P gas + P water 759.0 mmHg = P gas - 23.1 mmHg23.1 mmHg P gas = 735.9 mmHg or 0.9683 atm Calculate mass of butane in gas sample: Mass of butane = Initial mass – Final mass Calculate moles of butane in gas sample: PV = nRT Calculate molar mass for this Trial: Mass of butane / Moles of butane Trial 1 Atmospheric Pressure (P T ) 759.0 mmHg Water Temperature in K 24.5 C or 297.5 K Water vapor pressure at temperature recorded. 23.1 mmHg Initial Mass of Lighter 16.9523 g Final Mass of Lighter. 16.8501g Volume of gas sample in Liters 47.80 mL or 0.04780 L Click on number for water vapor table.

3. Water Vapor Pressure Table Temperature Pressure (°C) (mmHg) Temperature Pressure (°C) (mmHg) Temperature Pressure (°C) (mmHg) 0.0 4.6 5.0 6.5 10.0 9.2 12.5 10.9 15.0 12.8 15.5 13.2 16.0 13.6 16.5 14.1 17.0 14.5 17.5 15.0 18.0 15.5 18.5 16.0 19.9 16.5 19.5 17.0 20.0 17.5 20.5 18.1 21.0 18.6 21.5 19.2 22.0 19.8 22.5 20.4 23.0 21.1 23.5 21.7 24.0 22.4 24.5 23.1 25.0 23.8 26.0 25.2 27.0 26.7 28.0 28.3 29.0 30.0 30.0 31.8 35.0 42.2 40.0 55.3 50.0 92.5 60.0 149.4 70.0 233.7 80.0 355.1 90.0 525.8 95.0 633.9 100.0 760.0 Back to data slide

4. Finishing up the Gas Unit Data Calculations: Trial 1 Calculate pressure of gas sample: P T = P gas + P water Calculate mass of butane in gas sample: Mass of butane = Initial mass – Final mass 16.9523 g – 16.8501 g = 0.1002 g Calculate moles of butane in gas sample: PV = nRT Calculate molar mass for this Trial: Mass of butane / Moles of butane Trial 1 Atmospheric Pressure (P T ) 759.0 mmHg Water Temperature in K 24.5 C or 297.5 K Water vapor pressure at temperature recorded. 23.1 mmHg Initial Mass of Lighter 16.9523 g Final Mass of Lighter. 16.8501g Volume of gas sample in Liters 47.80 mL or 0.04780 L

5. Finishing up the Gas Unit Data Calculations: Trial 1 Calculate pressure of gas sample: P T = P gas + P water 759.0 mmHg = P gas + 23.1 mmHg P gas = 735.9 mmHg or 0.9683 atm Calculate mass of butane in gas sample: Calculate moles of butane in gas sample: PV = nRT 0.9863 atm ( 0.04780 L) = n (.0821 Latm/(molK) 297.5K 0.9863 X 0.04780 / 0.0821/297.5 = 0.001930 moles Calculate molar mass for this Trial: Mass of butane / Moles of butane Trial 1 Atmospheric Pressure (P T ) 759.0 mmHg Water Temperature in K 24.5 C or 297.5 K Water vapor pressure at temperature recorded. 23.1 mmHg Initial Mass of Lighter 16.9523 g Final Mass of Lighter. 16.8501g Volume of gas sample in Liters 47.80 mL or 0.04780 L

6. Finishing up the Gas Unit Data Calculations: Trial 1 Calculate pressure of gas sample: Calculate mass of butane in gas sample: Mass of butane = Initial mass – Final mass 16.9523 g – 16.8501 g = 0.1022 g Calculate moles of butane in gas sample: PV = nRT 0.001930 moles Calculate molar mass for this Trial: Mass of butane / Moles of butane 0.1022 g / 0.001930 = 52.95 g/mol Trial 1 Atmospheric Pressure (P T ) 759.0 mmHg Water Temperature in K 24.5 C or 297.5 K Water vapor pressure at temperature recorded. 23.1 mmHg Initial Mass of Lighter 16.9523 g Final Mass of Lighter. 16.8501g Volume of gas sample in Liters 47.80 mL or 0.04780 L