Procedure:
1. The mass of the lighter was measured using a triple beam balance before it was used in the experiment.
2. The volume of the jar was determined by filling the jar with water, then pouring the water into a graduated cylinder.
3. A plastic tub was prepared by filling it half full with tap water, and the water's temperature was recorded.
4. The empty jar was completely submerged in water in a plastic tub. All air bubbles were removed with a pipet.
5. The lighter was placed inside the jar while under water, and butane gas was released into the jar, as seen by the bubbles entering the jar.
6. After filling approximately half the jar with butane gas, the lid was secured tightly to the jar, and the jar removed from the water.
7. The temperature of the water was recorded at the conclusion of the experiment, in Celsius.
8.The mass of the lighter was measured again, on a triple beam balance, and recorded in grams.
9. Before discarding the water and gas mixture, the volume of the water and gas was measured, by pouring the liquid into a graduated cylinder, and its volume recorded in milliliters.
10. The contents of the jar were poured down the sink, and all other materials cleaned.
2. The volume of the jar was determined by filling the jar with water, then pouring the water into a graduated cylinder.
3. A plastic tub was prepared by filling it half full with tap water, and the water's temperature was recorded.
4. The empty jar was completely submerged in water in a plastic tub. All air bubbles were removed with a pipet.
5. The lighter was placed inside the jar while under water, and butane gas was released into the jar, as seen by the bubbles entering the jar.
6. After filling approximately half the jar with butane gas, the lid was secured tightly to the jar, and the jar removed from the water.
7. The temperature of the water was recorded at the conclusion of the experiment, in Celsius.
8.The mass of the lighter was measured again, on a triple beam balance, and recorded in grams.
9. Before discarding the water and gas mixture, the volume of the water and gas was measured, by pouring the liquid into a graduated cylinder, and its volume recorded in milliliters.
10. The contents of the jar were poured down the sink, and all other materials cleaned.
Data:
Volume of Jar: 254 mL
Volume of Water/Gas/Jar: 234 mL
Mass of Lighter BEFORE: 17.0 g
Mass of Lighter AFTER: 16.8 g
Temperature of Water BEFORE: 22.3 *C
Temperature of Water AFTER: 22.3*C
Pressure of Atmosphere: 1atm or 760 mmHg
Pressure of Water: 19.8 mmHg (determined based on a chart of temperatures and corresponding pressures, provided)
Volume of Water/Gas/Jar: 234 mL
Mass of Lighter BEFORE: 17.0 g
Mass of Lighter AFTER: 16.8 g
Temperature of Water BEFORE: 22.3 *C
Temperature of Water AFTER: 22.3*C
Pressure of Atmosphere: 1atm or 760 mmHg
Pressure of Water: 19.8 mmHg (determined based on a chart of temperatures and corresponding pressures, provided)
Calculations
Conclusion
Based on the experiment and following calculations, the molar mass of butane was found to be 248.942 grams/mole. This is significantly higher than the actual molar mas, with a percent error of over 400 percent. This large percentage of error is likely due to a variety of sources of error throughout the experiment. These include water getting into the lighter while butane gas was released, falsely increasing the final mass of the lighter. Furthermore, it was assumed that the temperature of the gas was the temperature of the water. This was done because while the two mix, it can be assumed that they reach some sort of equilibrium in temperature, and the temperature of the water will be very close to the temperature of the gas, but not exactly equal.
Analysis
1. Based on the calculations, the molar mas of the gas is 248.942 grams/mole.
2. A possible formula for the gas could be C19H21. This is determined by using the standard molar masses for carbon and hydrogen, and finding a ratio that adds up to the calculated molar mass of butane.
3. The percent error is 429.21%, as calculated by dividing the theoretical molar mass by the molar mas determined in the experiment and multiplied by 100:
58 x100= 429.21
248.942
4. a) If the temperature was in Celsius instead of Kelvin, the calculated molar mass would be lower because a smaller value for temperature would be plugged into the ideal gas law equation, producing a smaller number of moles. This smaller number of moles would result in a lower molar mass, because molar mass is calculated by diving moles by grams.
b) If the pressure was not corrected for the vapor pressure of water, the molar was would be lower than the actual because a higher pressure would be used in the ideal gas law equation, producing a larger number of moles, and dividing the grams by a larger moles would result in a smaller molar mass.
c) If there were air bubbles in the flask before the gas was released into it, the molar mass calculated would be lower than the acutal mass because the air bubbles would increase the volume measured. This higher volume will cause the number of moles calculated to be higher when used in the ideal gas law equation, creating a larger molar mass when divided by the grams.
d) If the lighter was not completely dry when weighed a second time, the molar mass would be lower than the real molar mass. This is because the water remaining in the lighter increases the final mass of the lighter, causing the difference in mass (the mass of the gas to be lower), resulting in a lower molar mass.
5. The other gases in lighter fluid must have a molar mass greater than butane, based on the molar mass of butane calculated from the experiment. This is because the molar mass that was calculated for butane was almost four times as large as the actual molar mass. This large value means that there are other gases in the mixture, and their molar masses are larger than that of butane. If the molar masses are smaller, the molar mass calculated for butane would have been lower than the actual.
6. The substance inside the lighter is a liquid, before a phase change occurs that changes it into a gas. Inside the lighter, the liquid is held at a pressure higher than atmospheric pressure, with the molecules being held together with strong intermolecular forces. When the leaver is pulled down on the lighter, the pressure inside is lowered and the intermolecular forces are greatly weakened. The weakening of the intermolecular forces cause the molecules to spread far apart, forming a gas.
2. A possible formula for the gas could be C19H21. This is determined by using the standard molar masses for carbon and hydrogen, and finding a ratio that adds up to the calculated molar mass of butane.
3. The percent error is 429.21%, as calculated by dividing the theoretical molar mass by the molar mas determined in the experiment and multiplied by 100:
58 x100= 429.21
248.942
4. a) If the temperature was in Celsius instead of Kelvin, the calculated molar mass would be lower because a smaller value for temperature would be plugged into the ideal gas law equation, producing a smaller number of moles. This smaller number of moles would result in a lower molar mass, because molar mass is calculated by diving moles by grams.
b) If the pressure was not corrected for the vapor pressure of water, the molar was would be lower than the actual because a higher pressure would be used in the ideal gas law equation, producing a larger number of moles, and dividing the grams by a larger moles would result in a smaller molar mass.
c) If there were air bubbles in the flask before the gas was released into it, the molar mass calculated would be lower than the acutal mass because the air bubbles would increase the volume measured. This higher volume will cause the number of moles calculated to be higher when used in the ideal gas law equation, creating a larger molar mass when divided by the grams.
d) If the lighter was not completely dry when weighed a second time, the molar mass would be lower than the real molar mass. This is because the water remaining in the lighter increases the final mass of the lighter, causing the difference in mass (the mass of the gas to be lower), resulting in a lower molar mass.
5. The other gases in lighter fluid must have a molar mass greater than butane, based on the molar mass of butane calculated from the experiment. This is because the molar mass that was calculated for butane was almost four times as large as the actual molar mass. This large value means that there are other gases in the mixture, and their molar masses are larger than that of butane. If the molar masses are smaller, the molar mass calculated for butane would have been lower than the actual.
6. The substance inside the lighter is a liquid, before a phase change occurs that changes it into a gas. Inside the lighter, the liquid is held at a pressure higher than atmospheric pressure, with the molecules being held together with strong intermolecular forces. When the leaver is pulled down on the lighter, the pressure inside is lowered and the intermolecular forces are greatly weakened. The weakening of the intermolecular forces cause the molecules to spread far apart, forming a gas.