The condensed vapor (ie, the remaining liquid) has the same mass as the vapor which exactly filled the flask be sure the foil cap is not wet from boiling water or condensed water vapor dry the neck of the flask, if necessary, keeping the foil cover on. This preview has intentionally blurred sectionssign up to view the full version view full document. The molecular weight of a condensable vapor can be determined by adding an excess of the corresponding liquid to a weighed flask, heating the flask to evaporate all of the liquid and to force out the excess vapor, cooling the vapor remaining in the flask so that it condenses, and then weighing the flask and condensed liquid the mass of the. Observations • during step 9, as the water was being heated, the unknown liquid began boiling at 72°c and a vapor began rising from the flask at about 85°c • • • the water in the 1 liter beaker began boiling violently at 100°c.
Ap chemistry post-lab report student name and block jordan holmes 4 th block lab title molecular weight of a condensable vapor claims 1) to volatize a liquid means to cause it to become a vapor. 1 the molar mass of a condensable vapor reading assignment: chang, chemistry, 10th edition, pp 85-87 185-187 goals to determine the molar mass of a condensable vapor through use of the ideal gas law. Introduction: determination of the molecular weight of a volatile liquid by the dumas method the dumas method is one of the simplest ways to measure the molecular weight of a substance it uses the ideal gas law. Gas density, molecular weight and density iso-pentane 7215 propane c 3h water vapor h 2o 18016 0804 0048 water gas (bituminous) 0054 methyl alcohol 3204 methyl.
When a steam phase separates from boiling water, co 2 is the dominant (over 90 % by weight) non-condensable gas (ncg) other species, such as hydrogen sulphide, sulphur dioxide, methane, hydrogen or ammonia, may also be present in low or very low concentrations. The molecular weight of a substance, also called the molar mass, m, is the mass of 1 mole of that substance, given in m gram in the si system the unit of m is [kg/kmol] and in the english system the unit is [lb/lbmol], while in the cgs system the unit of m is [g/mol.
A sample of vapor weighing 0745 g filled a 250 ml flask when placed in a water bath at 98 degrees celsius the barometric pressure that day was 753 torr calculate the volume of the vapor at stp, and the weight of one mol of the volitile liquid. Mw i is the molecular weight of the condensable species mw j is the molecular weight of the non-condensable species in the ratio of the partial and vapor. Chem 121l general chemistry laboratory revision 12 determination of the molecular weight of a volatile liquid learn about the gas laws learn about the dumas method of molecular weight determinations. Determinacion del peso molecular de un vapor condensable mediante el metodo de dumas molecular weight determination of a condensable vapor by the method of dumas.
Non-condensable gases seriously reduce the free convection film condensation heat transfer on surfaces with greater reductions when the gas molecular weight is smaller than that of the vapor (m ng m v. The molecular weight of ethyl acetate was determined in this experiment using a formula derived from the ideal gas law and experimental measurements of mass, volume, temperature and pressure of the sample. Set the term vapor is often used to describe the gaseous form of a substance which exists as a liquid or a solid under ordinary circumstances standard temperature is defined as 273 k standard pressure is defined as 1 atmosphere, or 760 torr.
A: first, it has to be able to vaporize below the boiling point of water, second, in it's vapor form, it has to be heavier than air as to not escape conclusions from this lab it is determined that the molecular mass of methanol is 254g/mole. The molecular weight of a condensable vapor can be determined by adding an excess of the corresponding fluid to a weighed flask, heating the assembly to volatilize all the liquid and to expel the excess vapor, cooling, and then weighing the flask with the condensed liquid. Molecular weight of a condensable vapor lab report let's experimentally determine the molecular weight of a condensable vapor you need this equipment : 6-cm-square thin aluminum foil, barometer, 200-ml graduated cylinder, 125-ml flask, rubber band, bunsen burner, iron ring, wire gauze, ring stand, pin, analytical balance, 600-ml beaker, iron. From your data, calculate the moles of vapor and the molecular weight of the vapor 2 what does the flask contain (a) before adding the volatile liquid (b) at the point when the volatile liquid has completely vaporized (c) at the end of the experiment, at the final weighing 3.
The molecular weight was smaller than expected this happened because the density was smaller due to the mass being smaller and this meant too much vapor escaped the flask conclusion: in this experiment, the molecular weight of a condensed vapor was found through a procedure using an unknown liquid. As far as molecular weight is concerned, generally lower mw molecules will have a higher vapor pressure, lower boiling point, etc but it also depends on the intermolecular attractions (in my water v ether example, ether has a much higher mw than water, but also has a much higher vapor pressure. Molecular weight determination by the victor meyer method objective: to determine the molecular weight of an unknown liquid using the victor meyer apparatus introduction: the victor meyer method consists of vaporiizing a known weight of liquid in a chamber maintained at an appropriate and constant high temperature.