Conductometric and volumetric study of copper sulphate in aqueous ethanol solutions at different temperatures

Peer review under responsibility of Taibah University

Figures & data

Table 1 Densities and apparent molar volumes of solutions of copper sulfate in aqueous ethanol at different temperatures.

^a msolute (mol dm^−1)	298.15 K^b		303.15 K		308.15 K		313.15 K
	ρ (g cm^−1)	Vϕ (cm^3 mol^−1)	ρ (g cm^−1)	Vϕ (cm^3 mol^−1)	ρ (g cm^−1)	Vϕ (cm^3 mol^−1)	ρ (g cm^−1)	Vϕ (cm^3 mol^−1)
0% (EtOH–H2O)
0.01	0.9991	29.027  ±  0.140	0.9964	28.504 ± 0.060	0.9939	28.014 ± 0.044	0.9918	27.599 ± 0.110
0.02	1.0011	38.989 ± 0.080	0.9985	33.480 ± 0.054	0.9960	33.017 ± 0.059	0.9939	32.624 ± 0.071
0.03	1.0030	45.582 ± 0.071	1.0005	38.440 ± 0.054	0.9980	38.003 ± 0.058	0.9959	37.632 ± 0.056
0.04	1.0045	58.829 ± 0.070	1.0020	53.440 ± 0.054	1.0000	40.448 ± 0.047	0.9979	40.088 ± 0.031
0.05	1.0063	60.717 ± 0.080	1.0039	54.341 ± 0.073	1.0016	49.947 ± 0.052	0.9998	34.549 ± 0.007
20% (EtOH–H2O)
0.01	0.9841	36.414 ± 0.161	0.9811	35.858 ± 0.086	0.9760	34.894 ± 0.118	0.9750	34.703 ± 0.153
0.02	0.9861	41.504 ± 0.101	0.9831	40.980 ± 0.077	0.9780	40.072 ± 0.122	0.9770	39.892 ± 0.117
0.03	0.9880	46.577 ± 0.082	0.9851	42.625 ± 0.060	0.9800	41.737 ± 0.099	0.9791	38.057 ± 0.091
0.04	0.9893	64.530 ± 0.081	0.9865	58.958 ± 0.076	0.9819	45.142 ± 0.089	0.9810	42.349 ± 0.062
0.05	0.9909	69.050 ± 0.090	0.9879	68.698 ± 0.078	0.9831	61.798 ± 0.072	0.9822	59.564 ± 0.038
40% (EtOH–H2O)
0.01	0.9619	42.967 ± 0.181	0.9600	42.621 ± 0.097	0.9567	42.014 ± 0.125	0.9550	41.697 ± 0.179
0.02	0.9638	48.286 ± 0.110	0.9619	47.963 ± 0.078	0.9587	41.926 ± 0.124	0.9570	41.610 ± 0.141
0.03	0.9657	49.989 ± 0.081	0.9639	46.058 ± 0.062	0.9607	41.939 ± 0.116	0.9590	41.523 ± 0.108
0.04	0.9670	66.980 ± 0.080	0.9651	66.732 ± 0.078	0.9625	47.202 ± 0.092	0.9609	44.171 ± 0.078
0.05	0.9686	70.634 ± 0.111	0.9668	68.234 ± 0.089	0.9635	67.808 ± 0.080	0.9619	65.398 ± 0.044

a Standard uncertainty is 0.001 mol dm⁻¹.

b Uncertainty of temperature = 0.05 K.

Table 2 Limiting apparent molar volumes (Vϕ°) and experimental slopes (B_V) of copper sulfate in water, and aqueous ethanol solutions at different temperatures.

Solvent	Vϕ° (cm^3 mol^−1)	BV × 10^3 (cm^3 mol^−2 kg)
0% (EtOH–H2O)
298.15 K	1.175	2.711
303.15 K	3.108	2.298
308.15 K	10.385	1.640
313.15 K	14.696	1.288
20% (EtOH–H2O)
298.15 K	4.559	2.806
303.15 K	5.386	2.626
308.15 K	13.947	1.836
313.15 K	15.996	1.605
40% (EtOH–H2O)
298.15 K	16.400	2.348
303.15 K	17.292	2.208
308.15 K	19.618	1.702
313.15 K	21.969	1.485

Fig. 1 CuSO₄ partial molar volumes of transfer from H₂O to EtOH–H₂O solutions at different temperatures.

Table 3 Molar volume (V), Van der Waals volume (V_w), electrostriction volume (V_e) in (Cm³ mol⁻¹) and solvated radii (r_o) of copper sulfate in (EtOH–H₂O) mixed solvents at different temperatures.

Solvent	V	VW	Ve	ro (Å)
0% (EtOH–H2O)
298.15 K	248.442	164.220	−84.222	3.873
303.15 K	248.938	164.548	−84.390	3.875
308.15 K	249.410	164.860	−84.550	3.878
313.15 K	249.934	165.207	−84.727	3.880
20% (EtOH–H2O)
298.15 K	252.156	166.675	−85.480	3.892
303.15 K	252.743	167.063	−85.679	3.895
308.15 K	253.435	167.521	−85.914	3.898
313.15 K	253.977	167.878	−86.098	3.901
40% (EtOH–H2O)
298.15 K	257.672	170.321	−87.351	3.920
303.15 K	258.259	170.709	−87.549	3.923
308.15 K	258.982	171.187	−87.795	3.927
313.15 K	259.493	171.524	−87.968	3.929

Fig. 2 Copper sulfate solvated radii in H₂O and EtOH–H₂O at different temperatures.

Table 4 Limiting molar conductance (Λ°_m) for copper sulfate in aqueous ethanol from T = 298.15–313.15 K.

Solvent	Kraus-Bray	Shedlovsky
0% (EtOH–H2O)
298.15 K	121.50 ± 0.12	122.90 ± 0.12
303.15 K	123.01 ± 0.12	124.28 ± 0.12
308.15 K	132.97 ± 0.13	134.75 ± 0.13
313.15 K	140.25 ± 0.14	142.76 ± 0.14
20% (EtOH–H2O)
298.15 K	70.67 ± 0.07	71.59 ± 0.07
303.15 K	72.67 ± 0.07	72.55 ± 0.07
308.15 K	76.56 ± 0.07	77.99 ± 0.07
313.15 K	82.03 ± 0.08	83.22 ± 0.08
40% (EtOH–H2O)
298.15 K	58.68 ± 0.05	60.23 ± 0.06
303.15 K	64.02 ± 0.06	66.04 ± 0.06
308.15 K	65.44 ± 0.06	67.56 ± 0.06
313.15 K	69.73 ± 0.06	71.01 ± 0.07

Table 5 Association constant K_A and changes in Gibb’s energy (ΔG°_A) for used salt in water + EtOH at different temperatures.

Solvent	KA	ΔG°A (kJ mol^−1)
0% (EtOH–H2O)
298.15 K	56.98	−4.596
303.15 K	48.55	−4.489
308.15 K	45.54	−4.488
313.15 K	44.78	−4.541
20% (EtOH–H2O)
298.15 K	59.43	−4.645
303.15 K	50.23	−4.529
308.15 K	49.34	−4.582
313.15 K	47.67	−4.616
40% (EtOH–H2O)
298.15 K	61.23	−4.679
303.15 K	60.12	−4.737
308.15 K	58.88	−4.790
313.15 K	57.44	−4.610

Fig. 3 Plots of Walden product Λ_m°η_o/(S cm² mol⁻¹ kg m⁻¹ s⁻¹) against volume fraction φ_v for copper sulfate in water + ethanol from T = 298.15–313.15 K.

Table 6 Entropy change of association (ΔS°_A) and enthalpy change of association (ΔH°_A) for copper sulfate in used solvents at different temperature.

Solvent	(ΔS°A) (J mol^−1)	(ΔH°A) (kJ mol^−1)
0% (EtOH–H2O)
298.15 K	25.54	−12.213
303.15 K	25.47	−12.213
308.15 K	25.06	−12.213
313.15 K	24.50	−12.213
20% (EtOH–H2O)
298.15 K	20.02	−10.615
303.15 K	20.07	−10.615
308.15 K	19.57	−10.615
313.15 K	19.15	−10.615
40% (EtOH–H2O)
298.15 K	24.91	−12.108
303.15 K	24.31	−12.108
308.15 K	23.74	−12.108
313.15 K	23.94	−12.108

Table 7 Activation energy (E_a) for copper sulfate in EtOH–H₂O solvents.

Solvent	Ea (kJ mol^−1)
0% EtOH–H2O	8.216
20% EtOH–H2O	8.115
40% EtOH–H2O	8.053