Partial pressure units

The quantity consumed or produced is conveniently expressed in partial pressure units if the substance is a gas. Concentration units are convenient if the reactant or product is in solution. The time measurement is also expressed in whatever units fit the reaction microseconds for the explosion of household gas and oxygen, seconds or minutes for the burning of a candle, days for the rusting of iron, months for the rotting of wood. 

Solution The experimental conditions are consistent with Equation (11.26) so that kiAi was measured. The experimental result was reported as KgAi because the overall mass transfer coefficient was based on the equivalent gas-phase driving force expressed in partial pressure units rather than concentration units. Because a pure gas was sparged, kg oo and Kj = k . Equation (11.3) relates Kg and Ki through Henry s law constant. 

In vapour phase reactions, partial pressure units are often used in place of concentration in the rate equation, for example... 

Total pressure, required for detailed interpretation of the mass spectra, is determined with an ionization gauge (S). The gas inlet system (A, B, C) is used for calibration purposes. The relation between measured total pressure and the ion current of an injected specific gas permits calibration of the mass spectrometer in absolute partial pressure units or amps/torr. 

Fig. 3 Vertical distribution of dissolved oxygen (in noncalibrated partial pressure units) measured with open oxygen sensor Kisa downcast (O2 down) and upcast (02 up) FSI sensor measured pH (in noncalibrated pH units) and photometrically measured H2S (in xM) at St. 1770...

In almost every system, the Mettler Thermoanalyzer I was coupled to a quadrupole mass spectrometer, such as is illustrated in Figure 8.14 (37. 69i. The sample may be studied under vacuum 10"6 Tom or under higher pressures to 1 atm. The reaction chamber, R. is surrounded by the furnace and separated from the balance by a diffusion baffle. The evolved gases pass directly to the mass analyzer. F. which is connected to a recorder, J. through the mass spectrometer control panel. Total pressure is determined by an ionization gauge, S, which also permits the recording of the EGD curve (in this case, due to the pressure change in the system). The relation between measured total pressure and the ion current of the calibration gas permits calibration of the mass spectrometer in absolute partial pressure units or A/Torr. 

Gas-side mass transfer coefficient in partial pressure units, mol/ m s atm. 

During the isobaric periods (feed at pjj and purge at Pl) the solute moves at a velocity Ug. For a gas that can be assumed to be ideal and an isotherm in partial pressure units, the solute velocity is given by Eq. fl8-15dl. Normally, j = 1.0 and all of the adsorption sites are accessible to the small gas molecules. 

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