Małgorzata Krzeczkowska

Solubility of 1-Pentene Ice in Liquid Nitrogen and Argon at the Standard Boiling Points of the Solvents

The solubilities of 1-pentene ice in liquid nitrogen at a temperature of 77.4 K and in liquid argon at 87.3 K have been measured by the filtration method. The 1-pentene content in solution was determined using gas chromatography. The experimental value of the mole fraction solubility of 1-pentene ice in liquid nitrogen at 77.4 K is: (1.28±0.25)×10−7 and (4.11±0.44)×10−7 in liquid argon at 87.3 K. The Preston–Prausnitz method was used for calculation of the solubilities of 1-pentene ice in liquid nitrogen in the temperature range 64.0–90.0 K and in liquid argon in the temperature range 84.0–90.0 K. The parameters l12 were also calculated. At 90.0 K liquid argon is the better solvent for 1-pentene ice than is liquid nitrogen.

Preliminary Studies About Knowledge and Applications of Science Mnemonics by Polish Pupils

Abstract Mnemonic devices are specific ways, which during coding new information apply known elements for improving subsequent access to that information in the memory. Consequently, not much is known about techniques for optimizing recall performance with mnemonic devices or the suitability of using mnemonic devices in educational applications. Moreover, in literature there are a lot of examples in chemistry, biology, physics and mathematics mnemonics approaches, however in the related literature, there is a lack of current and reliable studies for this subject. In this original work we describe mnemonic methods from this point of view in the learning and teachings of science subjects. A large trumps of this article is the demonstration of the old well-known method of the learning/teaching in the new scene. This is the first article in literature that present actual data about this topic according to learning and studying the science subjects by mnemonic studies.

Solubility of Solid Hexane and Cyclohexane in Liquid Argon at 87.3 K

The solubilities of solid hexane and cyclohexane in liquid argon at 87.3 K have been measured by the filtration method. The hexane and cyclohexane content in solution was determined using gas chromatography. The solubilities of the C6 hydrocarbons in liquid argon at 87.3 K are (0.56 ± 0.11) × 10-7 mole fraction for hexane and (1.04 ± 0.30) × 10-7 mole fraction for cyclohexane. The Preston–Prausnitz method was used for calculation of the solubilities of solid hexane and cyclohexane in liquid argon in the temperature range 84–110 K. The values of the solvent–solute interaction constant l12 were also calculated.

Solubility of solid pentane, 2-methylbutane, and cyclopentane in liquid argon at 87.3 K

The solubilities of solid pentane, 2-methylbutane (isopentane), and cyclopentane in liquid argon at 87.3 K have been measured by the filtration method. The C5 hydrocarbon content in solution was determined using gas chromatography. The solubilities of the C5 hydrocarbons in liquid argon at 87.3K vary from 0.61 × 10−7 mole fraction for cyclopentane, to 1.37 × 10−7 mole fraction for pentane, and 8.83 × 10−6 mole fraction for 2-methylbutane. The Preston–Prausnitz method was used for calculation of the solubilities of solid C5 hydrocarbons in liquid argon in the temperature range 84–110 K and in liquid nitrogen in the range 64–90K. The values of the solvent–solute interaction constant l12 were also calculated.

Solubility of pentane, 2-methylbutane, and cyclopentane in liquid nitrogen at 77. 4 K

The solubilities of pentane, 2-methylbutane (isopentane) and cyclopentane were measured in liquid nitrogen at 77.4 K by the filtration method. The solubilities of the C5 hydrocarbons in liquid nitrogen at 77.4 K vary from 1.8×10−8 mole fraction for cyclopentane, to 3.0×10−8 mole fraction for pentane and 3.2×10−7 mole fraction for 2-metylbutane. Correlations between the solubilities of alkanes, alkenes and cyclic hydrocarbons in liquid nitrogen, and some properties of solutes [normal boiling point Tb, enthalpy of vaporization at normal boiling point ΔHb and the mean of the enthalpy of vaporization and the enthalpy of melting [(ΔHb+ΔHm)/2] are presented.