Electronegativity is determined by factors like the nuclear charge
Answer:
-2546 kJ
Explanation:
It is possible to obtain the enthalpy of a reaction from the sum of different intermediate reactions.
For the reaction:
4B(s) + 3O₂(g) → 2B₂O₃(s)
The intermediate reactions are:
A- B₂O₃(s) + 3H₂O(g) → 3O₂(g) + B₂H₆(g), ΔH°A= +2035 kJ
B- 2B(s) + 3H₂(g) → B₂H₆(g), ΔH°B= +36 kJ
C- H₂(g) + 1/2O₂(g) → H₂O(l), ΔH°C= -285 kJ
D- H₂O(l) → H₂O(g), ΔH°D= +44 kJ
2B = 4B(s) + 6H₂(g) → 2B₂H₆(g) ΔH°2B= +78 kJ
-2A = 6O₂(g) + 2B₂H₆(g) → 2B₂O₃(s) + 6H₂O(g) ΔH°-2A= -4070 kJ
-6C = 6H₂O(l) → 6H₂(g) + 3O₂(g) ΔH°-6C= +1710 kJ
-6D = 6H₂O(g) → 6H₂O(l) ΔH°-6D = -264 kJ
The sum of 2B - 2A - 6C - 6D produce:
4B(s) + 3O₂(g) → 2B₂O₃(s)
And the enthalpy is: ΔH°2B + ΔH°-2A + ΔH°-6C + ΔH°-6D = <em>-2546 kJ</em>
I hope it helps!
The sulphate solutions came from a recycling LIBs waste cathode materials, which were done by previous research; their content is shown in Table 1 [18]. Sodium carbonate (Na2CO3) was purchased from Nihon Shiyaku Reagent, Tokyo, Japan (NaCO3, 99.8%), for the chemical precipitation. CO2 was purchased from Air Product and Chemical, Taipei, Taiwan (CO2 ≥ 99%), to carry out the hydrogenation–decomposition method. Dowex G26 was obtained from Sigma-Aldrich (St. Louis, MO, USA) and was used as a strong acidic cation exchange resin, to remove impurities. Multi-elements ICP standard solutions were acquired from AccuStandard, New Haven, Connecticut State, USA. The nitric acid (HNO3) and sulfuric acid (H2SO4) were acquired from Sigma-Aldrich (St. Louis, MO, USA) (HNO3 ≥ 65%) (H2SO4 ≥ 98%) The materials were analyzed by energy-dispersive X-ray spectroscopy (EDS; XFlash6110, Bruker, Billerica, MA, USA), X-ray diffraction (XRD; DX-2700, Dangdong City, Liaoning, China), scanning electron microscopy (SEM; S-3000N, Hitachi, Tokyo, Japan), and inductively coupled plasma optical emission spectrometry (ICP-OES; Varian, Vista-MPX, PerkinElmer, Waltham, MA, USA). In order to
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control the hydrogenation temperature and heating rate, a thermostatic bath (XMtd-204;
