The General Gas Law Objectives 1 To Measure The Volume Temperature And Pressure Of Gases 2 To Apply Dalton S Law 3 1 (78.71 KiB) Viewed 68 times
The General Gas Law Objectives 1 To Measure The Volume Temperature And Pressure Of Gases 2 To Apply Dalton S Law 3 2 (47.86 KiB) Viewed 68 times
The General Gas Law Objectives 1 To Measure The Volume Temperature And Pressure Of Gases 2 To Apply Dalton S Law 3 3 (9.26 KiB) Viewed 68 times
The General Gas Law Objectives 1 To Measure The Volume Temperature And Pressure Of Gases 2 To Apply Dalton S Law 3 4 (22.05 KiB) Viewed 68 times
THE GENERAL GAS LAW OBJECTIVES 1. To measure the volume, temperature, and pressure of gases. 2. To apply Dalton's law. 3. To test the general gas law. SAFETY Goggles must be worn for the entire lab period. - Tirrill burners have open flames-take care not to catch hair, scarves, and/or sleeves on fire. Equipment can get very hot, so there is the danger of a serious burn. INTRODUCTION The general gas law gives the mathematical relationship between pressure, volume and temperature of a gas as the variables are changed from one set of conditions to another: P,V, P₂V₂ T₂ T₁ In this experiment you will measure the volume, temperature, and pressure of a gas for two sets of conditions: hot and cold. V₂, the volume of the cold gas, can be calculated from the general gas law using the other five measurements. This result can then be compared with the measured V₂ using percent difference, where the denominator is the average of the calculated and measured values: V₂(calculated) - % difference = (V₂ (calculated) + V₂ (measured))/2 x 100 The general gas law applies only to situations in which the number of molecules of gas in unchanged in the two sets of conditions. This experiment starts with a dry gas when hot, but ends up with a gas in contact with water when cool. A gas in contact with water always takes in some water molecules. This additional gas can be accounted for using Dalton's law, which states that the total pressure of a gas mixture equals the sum of all the partial pressures: Ptotal= PA + PB + .... The partial pressure (PA) is the pressure that gas A would exhibit if it were all alone at the temperature and volume of the mixture. For the cool gas in this experiment, the total pressure is the sum of the pressure of the dry gas and the pressure of the water vapor: Ptotal = Pdry gas + Pwater vapor or: Pory gas Ptotal-Pwater vapor The general gas law should apply for changes in temperature, volume, and pressure of the dry gas. The pressure due to the presence of water is called the vapor pressure of the water. It depends only on the temperature of the water in contact with the gas mixture, and it can be found in a table of water vapor pressures (see the last page). Due to the limited number of sinks, you will acquire trial 1 data with another person at your bench. As with all lab reports in this course, you may not work together to answer report questions. Any work you submit for a grade should be completed alone.
DATA Trial 1 Temperature of boiling water T 101.3°C (374-3K) Temperature of cool water 2 IS.7°C Barometric pressure Pi 29.90 in /Hg Vapor pressure of water 13.38 torr Partial pressure of cool air (calc) p P₂ 307k/torr 60.80 mL Volume of water in flask V2 Volume of flask with stopper V 360.70ML Volume of the cool air (calc) - Data partner for Trial 1: _Justin (remember, you may not work together on the report) Record data in the units actually measured (e.g., °C). It would be acceptable to also include the value converted into another unit (e.g., 18.0°C = 291.2 K). Each experimenter is responsible to do the unit conversions correctly even when data are shared. Trial 2 slip # 29.90
Trial 2 Experiment 12 Volume of water in flask: 52.0 mL Volume of flask with stopper: 296.2 mL Assume the barometric pressure and temperature of boiling water are the same as trial 1. Data slip 1 T(cool): 14.0°C
6. Calculate V₂ for trial 2 assuming the vapor pressure of water is zero. Does this make the % difference larger or smaller? 7. Suppose the procedure were changed so that the flask had been held under water without opening the stopcock for five minutes (= constant volume). Determine for trial 2 (use calculations as necessary) to determine the following: Volume of gas in the flask = Temperature of the cool gas = Vapor pressure of water (consider the amount of water in the flask in this case) = Pressure of cool dry gas (calculate) =
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