280 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 Viscosity and Density of Chrom Alum in Aqueous Poly (Ethylene Glycol) Solution at Different Temperature S. H. Merza Department of Chemistry, College of Education, Ibn-Al-Haitham, University of Baghdad Received in :13 September 2011 Accepted in : 16 November 2011 Abstract Density data of alum chrom in water and in aqueous solution of poly (ethylene glycol) (1500) at different temperatures (288.15, 293.15, 298.15) k have been used to estimate the apparent molar volume (Vθ), limiting apparent molar volume (Vθ˚) experimental slope (Sv) and the second derivative of limiting partial molar volume [δ2 θ v° /δ T2] p .The viscosity data have been analyzed by means of Jones –Dole equation to obtain coefficient A, and Jones – Dole coefficient B, Free activation energy of activation per mole of solvent, Δμ10* solute, Δμ20* the activation enthalpy ΔH*,and entropy, ΔS*of activation of viscous flow. These results have been discussed in terms of solute –solvent interaction and making/breaking ability of solute in the given solution. Key word :chrom alum,apparent molar volume ,Solute – solvent interaction Introduction Measurements of some bulk properties like density (ρ) and viscosity (η) provides insight into the intermolecular an arrangement of the components in solution and helps to understand the thermodynamic properties of solution [1]. Ion-water interactions are important throughout biology and chemistry. In chemistry, ions affect the rates of chemical reactions[2- 3],ion-exchange mechanisms, widely used for chemical separations[4]. Ions have long been classified as being either Kosmotropes (structure makers) or chaotropes (structure breakers) according to their relative abilities to induce the structuring of water. The degree of water 281 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 structuring determined the increase or decrease in viscosity in water due to added salt. The viscosity (η) of an aqueous salt solution typically has the following dependence on ion concentration (c)[5]: (1) Where η0 are the viscosity of solvent, A is a constant independent of concentration (c) , which characterize the ionic solute interaction [6] , the constant B, which is called the Jones- Dole[7] B coefficient , is the quantity that defines the degree of water structuring around the ions and has been measured for wide electrolyte in aqueous and non aqueous solution . The viscosity B coefficient is positive for all Kosmotropic ions and negative for chaotrpic ion. Different physical parameters ,such as partial molar volume, Vθ˚, second derivative of infinite dilution of the partial molar volume with temperature [δ2 θ v° /δ T2] p and the viscosity B coefficient were calculated ,the free energy of activation of viscous flow per mole of solvent (Δμ10*) and solute (Δμ20*) are calculated too . All these parameter are used to discuss the solute –solute and solute –solvent interaction in the binary solution of (alum chrom + water) and ternary solution of (alum + aqueous polyethylene glycol) at different concentrations and at different temperatures as well as the structure making /breaking tendency of the solute(Alum) in the given solution. Alum name is given to all the double salts having composition: MIMIII(SO4)2.12H2O. Chrom alum have the composition (KCr (SO4)2.12H2O) which is used in dyeing, for tanning leather and in photography (during fixing) for hardening of the negatives[8]. Experimental Section Material Chrom alum, BDH chemical (England), PEG was provided by Sigma- Aldrich chemicals. Bidistilled water was used, for the preparation of solution. Densities Measurement Densities were measured by using 25 mL pyKnometer, the volume of the pyKnometer were calibrated with deionized and doubly distilled water at (288.15, 293.15, 298.15) K. The densities of alum solution were determined by weights using balance Sartorius BL 210S (Germany) with an accuracy of 10-4gm after reaching thermal equilibrium with a water bath at the studied temperature, divided by the volume of pyKnometer. η /η0 =1 + A √ c +B c 282 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 Viscosities Measurement The viscosity of aqueous solution of chrom alum were determined using an ubbelhode type[9] viscometer. The temperature of the solution was maintained within ± 0.01K .The Viscosity (η) of solvent and aqueous solution of alum chrom were calculated from the relation[10] 2) ( where( ρ)is the density in gm.cm-3,(t) is the flow time in second ,(c cm2 s-2) is the viscometer constant. Results and Discussion The measured densities and viscosities of the binary solution of ( alum chrom + water ) and ternary solution of (alum+aqeous PEG) at different concentrations are represented in Table(1).Table(1)shows an increasing in density and viscosity with the increase alum chrom concentration in the solution over the whole concentration , and these values decrease with the increase of alum at the same concentration. The apparent molar volume Vθ (cm3.mol-1) for (alum + H2O) and (alum + PEG) calculated from density using the following standard expression.[11] Vθ = M2/ ρ0 - 103/c* (ρ/ρ0-1) (3) Where ρ, ρ0 are the density of solution and solvent respectively, c is the molar concentration of alum in (mol.L-1) M2 is its molar mass g.mol-1 . The values of the apparent molar volume of the investigated solute are given in Table (3). Apparent molar volume of electrolyte varies with square root of the molar concentration (over wide concentration rang) in accordance with Masson's Empirical relation[12]. CSVV Vθθ +=  (4) This type of equation is applicable to the ionic solute where Vθ˚ is a partial molar volume at infinite dilution or limiting apparent molar volume is regarded as ameasure of ion– solvent interaction and Sv is a measure of ion- ion interaction. The calculated values of Vθ˚ and Sv, from the intercept and slope of the plotes Vθ versus c are given in Table (4). It is evident from Table (4) the values of limiting apparent molar volume for (alum+H2O) are positive suggesting presence of strong ion– solvent interaction between ions and surrounding water molecule. Large positive Vθ˚ for (alum + PEG) than (alum + H2O), attributed to entrapped the ions in void formed during coiling of polymer in solution and there exists electrostatic attraction between these ions and polymer chain in addition, the interaction between ions and water. The Vθ˚ increase with increasing temperature for (alum + PEG) and η = cρ t 283 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 (alum+H2O) may be attributed to the increase in solvation of the ions. The values of Sv are negative for (alum + PEG) and (alum + H2O) which reflected that ion–ion interaction are very weak at entire temperature except at 288.15 K. The experimental values of Vθ˚ were related to temperature using the quadratic equation[13] Vθ˚ = a+ b T+c T2 (5) The coefficient a, b, c were determined and equ (5) has the following forms for alum chrom in water and aqueous solution PEG Vθ˚ = -13305+ 901.5 T-1.524 T2 for (alum+H2O) (6) Vθ˚ = -52804+ 354.0 T-0.59 T2 for (alum+PEG) (7) Thus, from equations (6and7), it can be observed that the values of [δ2 θ v° /δ T2] p are negative for (alum + PEG) and (alum + H2O) , indicating the structure breaking ability of alum in water and aqueous PEG. The viscosity data were analyzed by means of Jones – Dole equation [14] Where ηrel is the relative viscosity, C is the molar concentration. The viscosity coefficients A and B were obtained from the intercept and slope of the plots (ηrel -1)/ C1/2virsus C1/2 .The values of A and B are listed in Table (5). Perusal of Table(5)shows that the values of A are positive in(alum+H2O)and(alum + EG)at all temperature. Since A is considered to be a measure of ion–ion interaction, the positive values may be indicating the presence of ionic interactions in the solutions concerned. The coefficient B is important for a number of reasons[15]. First, the viscosity B coefficient provides information about solvation of solute and its effects on the structure of the solvent in the near environment of the solute molecule. Furthermore, some active parameter of viscous flow can be obtained using the viscosity B coefficient. The viscosity B coefficient, originally introduced as an empirical term, was found depend on solute – solvent interactions and on the relative size of solute and solvent [16]. It can be seen from Table (5) that the viscosity B coefficient are negative indicating the structure–breaking ability of alum chrom because solvent molecule attached to the ions (ion – solvent interaction) wrenched out of the bulk solvent and this breaking of the solvent causes a decrease in viscosity of solution .This conclusion is an excellent agreement with that drawn from the density measurement. The sign of temperature derivative of B coefficient (dB/ d T) gives the information of structure making / breaking ability of the solute in the solvent media. In general the (dB/ d T) is negative for structure maker and positive for structure breakers [17] . The temperature η rel = η / η0 =1+AC 1/2+BC (8) 284 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 coefficient (dB/ d T) are given in Table (5). From this table it can be seen that alum chrom act as structure breaker in aqueous PEG while it acts as structure maker in water this result is opposite to the result obtained from the density measurement . The viscosity data were also analyzed on the basis of the transition state as suggested by Feakins, et al[18] .according to which the viscosity B- coefficient was computed from the following relation Where V10 = MSOLVENT / d is the partial molar volume of solvent and V10 = θv0 is the partial molar volume of solute.Eyring and coworker[19] used the following relation for calculating Δμ10* , the free energy of activation of viscous flow per mole of pure solvent . This on rearrangement gives Δμ10* =RT ln η0 V10 / hN (11) Eq. (9) can be rearranged to give: Δμ20* = Δμ10*+ (RT/ V10) [1000B - (V10 - V20)] (12) Where Δμ20*contribution per mole of solute to free energy of activation for viscous flow of the solution , R,h and N are gas constant , Planck' s ,Avogadro Constant respectively , T, is the absolute temperature . The Δμ10* and Δμ20* values calculated from above equations are given in Table (6). It is clear from Table (6) that Δμ20* values are negative as compared to those of Δμ10*. This is due to the fact the alum in water and aqueous PEG behaves as structure breaker. This conclusion is in an excellent agreement with the conclusion drawn from density measurement. In fact Feakins et al [20] have shown the electrolyte has Δμ20*> Δμ10*act as structure makers. According to transition state theory every solvent molecule in one mole of solution must pass through the transition and interact more or less strongly with solute molecule. The activation free energy Δμ20*contains contribution from two effects: first, the activation energy of solvent molecule is affected by the interaction between solute and surrounding solvent molecule in the transition state ΔG20 * (1→1').and the second, the solute moves through its own transition state ΔG20 * (2→2'). The ΔG2 *˚(1→1') values obtained by the subtracting Δμ10* from Δμ20* as ΔG2 0* (2→2') is equivalent to Δμ10* [21.22] . It can be also noted that ΔG20 * (1→1') ( thermodynamic activation of transfer for alum from ground state to transition state in aqueous PEG ) and Δμ20* are negative except at 288.15 This can be explained by the fact that transfer of alum from ground state to transition state solvent is favored. The free energy of activation of viscous flow of solution , ΔG0*was calculated by using the equation B = 1/1000*[(V1 0 - V2 0) + V1 0 (Δμ2 0* - Δμ1 0*)/RT (9) η0 = hN/ V1 0 exp (Δμ1 0* /RT) (10) ΔG0*= n1 Δμ1 0*+ n2 Δμ2 0* (13) 285 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 Where n1and n2 are the number of moles of solvent and solute respectively. The enthalpy ΔH0*and entropy, ΔS0*of activation of viscous flow were computed using the equation The values, ΔH0* and, ΔS0* are obtained from the intercept and slop of Δμ0* versus T. The ΔH0* and, ΔS0* are summarized in Table (7) Table (7) shows positive ΔH0*values and increase of with increase concentration of chrom alum in water and aqueous PEG. The values of ΔS0* are positive for alum in water ΔS0* are negative for alum in aqueous PEG and decrease with increase of concentration this may be due to the fact that formation of activated species necessary for viscous flow appears difficult (ions binds strongly to water molecule ).. References 1. Yilmaz, H. ( 2002) Excess properties of Alcohol-water system at 298.15K Turk.J.Phys. 26:243-246 2. Maroncelli, M.; Maclnnins J. and Fleming, (1989) Polar solvent dynamics and electron- tranfer reaction G.R.,Science. 243: 1674-1681. 3. Kropman, X. and Bakker F. (2001) dynamics of water molecule in Aqueou solvation hells H.J.Science291: 2118-2120. 4. Habuchi , s.; Kim H.B.and Kitamura N. (2001) How Ion Affect the structure of water Anal.Chem.73:366-372. 5. Robinson, R. Aand StoKes, R.H.( 1959) Electrolyte Solution, Butterworth Scientific Publications: London 6. FalKenhagen, H. andVernon, E.L. (1932) The vicsoity and fluidity of aqueous Potassium Ferrocyamide solution Phys.Z.33: 140. 7. Harned, H.S. and own, B.B.(1958) The physical Chemistry of Electrolyte Solution, Reinhold, NewYorK, 3rd.edition, P.240 8. Madan, R.D. Modern, Reprint( 2009) Inorganic Chemistry, S.Chand & Company LTD.Ram Nagar, New Delhi 110 055. 9. StoKes, R.H. and Mills, R. (1965) Viscosity of electrolytes and related properties (New YorK: Pergamon) 10. Cannon, M.R.; Manning R.E. and Bell, J.D.(1960) Vicosity meaurment~ the Kinetic energy correction and anew viscometer .Analytical chemistry 32:355-358. 11. Harned, H.S. and Owen, B.B. (1958) The physical chemistry of electrolyte solution, 3rd edn(Reinhold,New YorK) P358 12. Masson, D. O. (1929) solute molecular volume in relation to solvation and ionization philos. Mag. 8: 218. 13. Water Comprehensive Treatise(1978) Vol.ΙV: F.FranKs, Ed., Plenum Press, NewYork. 14. Jones, G. and Dole, M. (1929) Viscosity of aqueous olution of strong electrolytes with special refrence of barium chloride J.Am.Chem.Soc.51: 2950. 15. Bhattacharyya, M.M. and Sengupta, M. (1982) (N.F.) Viscosity B- coefficient and standard partial molar volume of amino acids and their roles in interpreting the protein(enzyme) stabilization) Z.Phys.Chem. 133: 79. 16. Jenkins H.D.B.and Marcus Y. (1995) Viscosity B- coefficient of Ions in solution, Chem.Rev 95: 2695. ΔG0*= ΔH0*-T ΔS0* (14) 286 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 17. Ali, A.; Sabir, S. ;Nain, A.K.; Ahmad, S.; Tariq M. and .Patel, (2007) Interaction of phenyle alanine ,Tyrosine and Hitidine in Aqueous caffeine solutions at different Tempretures J.Chinese.Chem.Soc, 54:659 18. Feakins, D.; Canning, F.M.; Waghorne, W.E. and Lawrence, K.G. (1993) Trans.Interactions of poline in non aqueous Anionic , cationic and nonionic surfactant at different Tempretures J.Chem.Soc.Faraday 89: 3381. 19. Glasstone, S.; Laidler, K.J . and Eyring, H. (1941) The theory of Rate Processes, Mc Graw Hill, New YorK. 20. Feakins, D.; Freemantle, D.J. and Lawrence, K.G. (1974) The properties of mixtures of sodium Dodecylsulfate and Diethyl sulfoxide in water, J.Chem.Soc. Faraday Trans,I70: 795. 21. Yan, Z.;Wang, J. &Lu. J. (2002) Effect of sodium caproate on the volumetric properties of glycine, DL- α – alanine ,and DL- α – amino –n-butyric acid in aqueous solutions Biophys.Chem,99: 199. 22. Feakins, D.; Waghhorn, W.E. and Lawrence, K.G. (1986) Faraday Trans.,Effect of temoerature on viscosity of some α –amino acids in aqueous urea solutions J.Chem.Soc. 182: 563. Table (1): Experimental densities ρ(g.cm-3) and viscosities η (cp) for (alum + H2O) C mol.L-1 (alum + H2O) 288.15K 293.15K 298.15K ρ(g.cm-3) η (cp) ρ(g.cm-3) η (cp) ρ(g.cm-3) η (cp) 0.00 0.99910 1.224397 0.99821 1.002892 0.99704 0.888363 0.010 1.00242 1.250646 1.000561 1.109956 0.99922 1.009914 0.015 1.00361 1.260936 1.00203 1.119151 1.00094 1.017314 0.020 1.00483 1.270005 1.00335 1.129733 1.00287 1.02432 0.025 1.00638 1.282531 1.0047 1.133897 1.00416 1.031425 0.030 1.00757 1.289186 1.00602 1.144267 1.00533 1.038816 0.035 1.00934 1.298112 1.00738 1.153907 1.0069 1.047776 287 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 0.040 1.01053 1.310556 1.00894 1.16308 1.00883 1.053939 Table (2): Experimental densities ρ(g.cm-3) and viscosities η (cp) for (alum + PEG) C mol.L-1 (alum +PEG) 288.15K 293.15K 298.15K ρ(g.cm- 3) η (cp) ρ(g.cm-3) η (cp) ρ(g.cm-3) η (cp) 0.00 1.00194 1.235103 1.00086 1.050903 0.99983 0.936141 0.01 1.00472 1.360592 1.00321 1.194255 1.00122 1.082564 0.015 1.00594 1.366469 1.00405 1.20851 1.00277 1.098063 0.020 1.00753 1.381324 1.00579 1.223742 1.00422 1.112806 0.025 1.00902 1.390026 1.00747 1.230936 1.00542 1.122523 0.030 1.01038 1.402812 1.00899 1.249726 1.00695 1.137233 0.035 1.01152 1.413163 1.01132 1.261996 1.00879 1.141376 0.040 1.01346 1.424722 1.01191 1.275605 1.00998 1.151452 288 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 Table (3): Apparent molar volume of (alum + H2O) and (alum + EG) at different temperature Vθ (Alum + H2O) C /mol.L-1 298.15 K 293.15 K 288.15 K 278.244 268.784 167.560 0.010 237.455 244.516 198.922 0.015 206.529 242.346 213.101 0.020 213.651 239.841 208.397 0.025 222.410 239.173 217.272 0.030 217.204 237.551 207.024 0.035 204.272 231.326 213.852 0.040 Vθ (alum + PEG) C / mol.L-1 298.15 K 293.15 K 288.15 K 357.471 258.203 216.997 0.010 301.460 282.517 229.640 0.015 278.455 249.710 217.496 0.020 274.654 232.424 214.203 0.025 261.118 226.229 216.332 0.030 242.591 198.679 224.127 0.035 244.949 221.482 210.011 0.040 289 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 Table (4): Values of partial molar volume (Vθ˚) in (cm3.mol-1) experimental slop (Sv) in (cm3.mol-2.L) for (Alum + H2O)and (alum + PEG) at different temperature. Table(5): values of parameters, A(L1/2.mol-1/2)and B(L.mol1/2) of Jones–Dole equation in(alum+H2O) and (alum + PEG) and the values of (dB/ d T) T/K 2O Alum + H A(L1/2.mol-1/2) B(L.mol-1) (dB/ d T) 288.15 0.081 1.322 -1.1076 293.15 1.284 -2.625 -0..6276 Alum +H2O T/K Sv Vθ˚ 5.687 180.9 288.15 -4.088 259.0 293.15 -8.804 260.9 298.15 Alum + PEG T/K Sv Vθ˚ -2.175 226.2 288.15 -11.27 281.6 293.15 -13.53 307.5 298.15 290 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 298.15 1.718 -4.165 -0.1476 T/K Alum+PEG A(L1/2.mol-1/2) B(L.mol-1) (dB/ d T) 288.15 1.181 -2.249 0.3907 293.15 1.591 -2.834 0.2807 298.15 1.924 -4.008 0.1707 Table (6): Free energy of activation per mole of solvent, Δμ10*and solute, Δμ20*of alum in water and aqueous PEG at different temperatures T/K Alum + H2O Δμ1 0*(KJ mole-1) Δμ2 0*(KJ mole-1) 288.15 59.25 197.50 293.15 59.80 -322.16 298.15 60.52 -526.87 T/K Alum+PEG Δμ1 0*(KJ mole-1) Δμ2 0*(KJ mole-1) 288.15 69.87 -272.08 293.15 70.69 -348.27 298.15 71.61 -511.93 291 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 Table(7): enthalpies, ΔH*and entropies,ΔS*of activation of viscous flow of(alum + H2O)and(alum+ EG) C / mol.L-1 Alum + H2O ΔH0* (KJ mole-1) ΔS0* (J mole-1K-1) 0.01 1633 5716 0.015 1776 5209 0.02 1818 5053 0.025 1941 4617 0.03 2032 4290 0.035 2176 3784 0.04 2244 3530 C / mol.L-1 Alum+PEG ΔH0* (KJ mole-1) ΔS0* (J mole-1K-1) 0.01 66.73 -238 0.015 100.0 -358 0.02 133.2 -478 0.025 166.5 -598 0.03 199.8 -718 0.035 233.0 -838 0.04 266.3 -958 292 مجلة إبن الهيثم للعلوم الصرفة و التطبيقية 2012 السنة 25 المجلد 2 العدد Ibn Al-Haitham Journal for Pure and Applied Science No. 2 Vol. 25 Year 2012 لزوجة وكثافة شب الكروم في محلول بولي اثلين كاليكول درجات حرارية مختلفةب سندس هادي مرزا ابن الهيثم ،جامعة بغداد -قسم الكيمياء ، كلية التربية 2011ول تشرين األ 16قبل البحث في : 2011أيلول 13استلم البحث في : الخالصة اســتعملت المعلومــات التــي تــم الحصــول عليهــا مــن قيــاس الكثافــة لمحاليــل شــب الكــروم فــي المــاء وفــي المحلــول مطلقــة (299.15,293.15,298.15)وبــدرجات حــرارة مختلفــة 1500المــائي للبــولي اثلــين كاليكــول ذي الــوزن الجزيئــي والمشــتقة الثانيــة للحجــم المـــوالري ،)Sv، والميــل ()˚Vθوالحجــم الظـــاهري المحــدد (، )Vθ( إليجــاد الحجــم المــوالري الظــاهري . اسـتعملت معادلـة جـونز ودول لمعالجـة المعلومـات مـن قياسـات p [δ2 θ v° /δ T2]المحـدد مـع درجـة الحـرارة بثبـوت الضـغط , *Δμ10* Δμ20من المذيب والمذاب ، وطاقة التنشيط الحرة لكل مول Bجونز ودول ومعامل ، Aاللزوجة إليجاد المعامل علـى أسـاس تـأثيرات متبادلـة مـن نـوع للجريان اللزج . نوقشت هذه النتـائج *ΔS0 وانتروبي التنشيط *ΔH0وانثالبي التنشيط مذيب، وعلى قابلية المذاب على الهدم والبناء في المحلول. . –ايون مذيب -لظاهري ، تأثيرات متبادلة مذاب: شب الكروم ، الحجم الموالري ا الكلمات المفتاحية