{"title":"Heat of Formation of Calcium Aluminate Monosulfate at 25 °C.","authors":"H A Berman, E S Newman","doi":"10.6028/jres.067A.001","DOIUrl":null,"url":null,"abstract":"<p><p>The heat of formation of calcium aluminate monosulfate, 3CaO·Al<sub>2</sub>O<sub>3</sub>·CaSO<sub>4</sub>·12H<sub>2</sub>O, at 25 °C, and of less completely hydrated samples of the same compound, was determined by the heat-of-solution method, with 2<i>N</i> HCl as the solvent, and 3CaO·Al<sub>2</sub>O<sub>3</sub>·6H<sub>2</sub>O(c) and CaSO<sub>4</sub>·2H<sub>2</sub>O(c), as the reactants. The results were as follows: Δ<i>H, kj/mole</i>Δ<i>H, kcal/mole</i>3CaO·Al<sub>2</sub>O<sub>3</sub>·CaSO<sub>4</sub>·12H<sub>2</sub>O(c) Heat of formation from elements, <math><mrow><mi>Δ</mi> <msubsup><mi>H</mi> <mi>f</mi> <mo>°</mo></msubsup> </mrow> </math> -2100 from reactants and H<sub>2</sub>O(1)-15.0 Heat of solution in 2<i>N</i> HCl- 495.7- 118.5 Change of heat of solution with H<sub>2</sub>O content at 12H<sub>2</sub>O, per mole H<sub>2</sub>O <math> <mrow> <mfrac><mrow><mi>d</mi> <mrow><mo>(</mo> <mrow><mi>Δ</mi> <mi>H</mi></mrow> <mo>)</mo></mrow> </mrow> <mrow><mi>d</mi> <mi>n</mi></mrow> </mfrac> </mrow> </math> 1.93 The heat of the reaction (Δ<i>H</i>) <dispformula> <math> <mtable> <mtr><mtd><mn>3</mn> <mi>CaO</mi> <mo>⋅</mo> <msub><mi>Al</mi> <mn>2</mn></msub> <msub><mi>O</mi> <mn>3</mn></msub> <mo>⋅</mo> <msub><mi>CaSO</mi> <mn>4</mn></msub> <mo>⋅</mo> <mn>12</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi> <mrow><mo>(</mo> <mi>c</mi> <mo>)</mo></mrow> <mo>+</mo> <mn>2</mn> <mrow><mo>(</mo> <mrow> <msub><mrow><mi>CaSO</mi></mrow> <mn>4</mn></msub> <mo>⋅</mo> <mn>2</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi></mrow> <mo>)</mo></mrow> <mrow><mo>(</mo> <mi>c</mi> <mo>)</mo></mrow> <mo>+</mo> <mn>15</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi> <mrow><mo>(</mo> <mi>l</mi> <mo>)</mo></mrow> <mo>→</mo></mtd> </mtr> <mtr><mtd><mn>3</mn> <mi>CaO</mi> <mo>⋅</mo> <msub><mi>Al</mi> <mn>2</mn></msub> <msub><mi>O</mi> <mn>3</mn></msub> <mo>⋅</mo> <mn>3</mn> <msub><mi>CaSO</mi> <mn>4</mn></msub> <mo>⋅</mo> <mn>31</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi> <mrow><mo>(</mo> <mi>c</mi> <mo>)</mo></mrow> </mtd> </mtr> </mtable> </math> </dispformula> is -134.4 kj/mole or -32.1 kcal/mole. The heat of the reaction (Δ<i>H</i>) <dispformula> <math> <mtable> <mtr><mtd><mn>3</mn> <mi>CaO</mi> <mo>⋅</mo> <msub><mi>Al</mi> <mn>2</mn></msub> <msub><mi>O</mi> <mn>3</mn></msub> <mo>⋅</mo> <msub><mi>CaSO</mi> <mn>4</mn></msub> <mo>⋅</mo> <mn>12</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi> <mrow><mo>(</mo> <mi>c</mi> <mo>)</mo></mrow> <mo>+</mo> <mn>2</mn> <mrow><mo>(</mo> <mrow> <msub><mrow><mi>CaSO</mi></mrow> <mn>4</mn></msub> <mo>⋅</mo> <mn>2</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi></mrow> <mo>)</mo></mrow> <mrow><mo>(</mo> <mi>c</mi> <mo>)</mo></mrow> <mo>+</mo> <mn>16</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi> <mrow><mo>(</mo> <mi>l</mi> <mo>)</mo></mrow> <mo>→</mo></mtd> </mtr> <mtr><mtd><mn>3</mn> <mi>CaO</mi> <mo>⋅</mo> <msub><mi>Al</mi> <mn>2</mn></msub> <msub><mi>O</mi> <mn>3</mn></msub> <mo>⋅</mo> <mn>3</mn> <msub><mi>CaSO</mi> <mn>4</mn></msub> <mo>⋅</mo> <mn>32</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi> <mrow><mo>(</mo> <mi>c</mi> <mo>)</mo></mrow> </mtd> </mtr> </mtable> </math> </dispformula> is -144.9 kj/mole or -34.6 kcal/mole. Values reported earlier for the heat of formation of calcium aluminate trisulfate and of calcium aluminate monocarbonate should be revised by adding -0.9 kcal/mole to each reported Δ<i>H</i> value, with the following resulting values: Δ<i>H</i> from appropriate reactants <math><mrow><mi>Δ</mi> <msubsup><mi>H</mi> <mi>f</mi> <mo>°</mo></msubsup> </mrow> </math> <i>kcal/mole</i> <i>kcal/mole</i>3CaO·Al<sub>2</sub>O<sub>3</sub>·3CaSO<sub>4</sub>·31H<sub>2</sub>O(c) -47.01 -41233CaO·Al<sub>2</sub>O<sub>3</sub>·3CaSO<sub>4</sub>·32H<sub>2</sub>O(c) -49.52 -41943CaO·Al<sub>2</sub>O<sub>3</sub>·CaCO<sub>3</sub>·10·68H<sub>2</sub>O(c) -19.77 -1957 Conditions for the formation of the monosulfate from solution, and its properties on exposure to moisture, are discussed.</p>","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"1963-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5324954/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.6028/jres.067A.001","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"1963/2/1 0:00:00","PubModel":"Epub","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The heat of formation of calcium aluminate monosulfate, 3CaO·Al2O3·CaSO4·12H2O, at 25 °C, and of less completely hydrated samples of the same compound, was determined by the heat-of-solution method, with 2N HCl as the solvent, and 3CaO·Al2O3·6H2O(c) and CaSO4·2H2O(c), as the reactants. The results were as follows: ΔH, kj/moleΔH, kcal/mole3CaO·Al2O3·CaSO4·12H2O(c) Heat of formation from elements, -2100 from reactants and H2O(1)-15.0 Heat of solution in 2N HCl- 495.7- 118.5 Change of heat of solution with H2O content at 12H2O, per mole H2O 1.93 The heat of the reaction (ΔH) is -134.4 kj/mole or -32.1 kcal/mole. The heat of the reaction (ΔH) is -144.9 kj/mole or -34.6 kcal/mole. Values reported earlier for the heat of formation of calcium aluminate trisulfate and of calcium aluminate monocarbonate should be revised by adding -0.9 kcal/mole to each reported ΔH value, with the following resulting values: ΔH from appropriate reactants kcal/molekcal/mole3CaO·Al2O3·3CaSO4·31H2O(c) -47.01 -41233CaO·Al2O3·3CaSO4·32H2O(c) -49.52 -41943CaO·Al2O3·CaCO3·10·68H2O(c) -19.77 -1957 Conditions for the formation of the monosulfate from solution, and its properties on exposure to moisture, are discussed.
以 2N HCl 为溶剂,3CaO-Al2O3-6H2O(c) 和 CaSO4-2H2O(c)为反应物,通过溶解热法测定了单硫酸铝酸钙(3CaO-Al2O3-CaSO4-12H2O)在 25 °C 时的形成热,以及同一化合物的不完全水合样品的形成热。结果如下元素形成热,Δ H f ° -2100 来自反应物和 H2O(1)-15.0 2N HCl- 中的溶液热 495.7- 118.5 12H2O 时溶液热随 H2O 含量的变化,每摩尔 H2O d ( Δ H ) d n 1.93 3 CaO ⋅ Al 2 O 3 ⋅ CaSO 4 ⋅ 12 H 2 O ( c ) + 2 ( CaSO 4 ⋅ 2 H 2 O ) ( c ) + 15 H 2 O ( l ) → 3 CaO ⋅ Al 2 O 3 ⋅ 3 CaSO 4 ⋅ 31 H 2 O ( c ) 的反应热(ΔH)为-134.4 千焦/摩尔或-32.1 千卡/摩尔。反应热 (ΔH) 3 CaO ⋅ Al 2 O 3 ⋅ CaSO 4 ⋅ 12 H 2 O ( c ) + 2 ( CaSO 4 ⋅ 2 H 2 O ) ( c ) + 16 H 2 O ( l ) → 3 CaO ⋅ Al 2 O 3 ⋅ 3 CaSO 4 ⋅ 32 H 2 O ( c ) 为-144.9 千焦/摩尔或-34.6 千卡/摩尔。先前报告的三硫铝酸钙和单碳酸铝酸钙的形成热值应通过在每个报告的 ΔH 值上添加 -0.9 千卡/摩尔来修正,得出以下值: 来自适当反应物的 ΔH ΔH f ° 千卡/摩尔 千卡/摩尔3CaO-Al2O3-3CaSO4-31H2O(c) -47.01 -41233CaO-Al2O3-3CaSO4-32H2O(c) -49.52 -41943CaO-Al2O3-CaCO3-10-68H2O(c) -19.77 -1957 讨论了从溶液中形成单硫酸盐的条件及其受潮后的性质。