{"title":"298 至 1,200 °K 的氧化镁和氧化铍的热力学性质。","authors":"Andrew C Victor, Thomas B Douglas","doi":"10.6028/jres.067A.034","DOIUrl":null,"url":null,"abstract":"<p><p>As a step in developing new standards of high-temperature heat capacity and in determining accurate thermodynamic data for simple substances, the enthalpy (heat content) relative to 273 °K, of high purity fused magnesium oxide, MgO, and of sintered beryllium oxide, BeO, was measured up to 1,173 °K. A Bunsen ice calorimeter and the drop method were used. The two samples of BeO measured had surface-to-volume ratios differing by a factor of 15 or 20, yet agreed with each other closely enough to preclude appreciable error attributable to the considerable surface area. The enthalpies found for MgO are several percent higher than most previously reported values. The values are represented within their uncertainty (estimated to average ± 0.25%) by the following empirical equations (cal mole<sup>-1</sup> at <i>T</i> °K) <dispformula> <math> <mtable> <mtr><mtd><mtext>MgO</mtext> <mo>:</mo> <msubsup><mi>H</mi> <mi>T</mi> <mo>°</mo></msubsup> <mo>-</mo> <msubsup><mi>H</mi> <mrow><mn>273.15</mn></mrow> <mo>°</mo></msubsup> <mo>=</mo> <mn>10.7409</mn> <mi>T</mi> <mo>+</mo> <mn>1.2177</mn> <mrow><mo>(</mo> <mrow> <msup><mrow><mn>10</mn></mrow> <mrow><mo>-</mo> <mn>3</mn></mrow> </msup> </mrow> <mo>)</mo></mrow> <msup><mi>T</mi> <mn>2</mn></msup> <mo>-</mo> <mn>2.3183</mn> <mrow><mo>(</mo> <mrow> <msup><mrow><mn>10</mn></mrow> <mrow><mo>-</mo> <mn>7</mn></mrow> </msup> </mrow> <mo>)</mo></mrow> <msup><mi>T</mi> <mn>3</mn></msup> <mo>+</mo> <mn>2.26151</mn> <mrow><mo>(</mo> <mrow> <msup><mrow><mn>10</mn></mrow> <mn>5</mn></msup> </mrow> <mo>)</mo></mrow> <msup><mi>T</mi> <mrow><mo>-</mo> <mn>1</mn></mrow> </msup> <mo>-</mo> <mn>3847.94</mn> <mo>.</mo></mtd> </mtr> <mtr><mtd><mtext>BeO</mtext> <mo>:</mo> <msubsup><mi>H</mi> <mi>T</mi> <mo>°</mo></msubsup> <mo>-</mo> <msubsup><mi>H</mi> <mrow><mn>273.15</mn></mrow> <mo>°</mo></msubsup> <mo>=</mo> <mn>11.1084</mn> <mi>T</mi> <mo>+</mo> <mn>7.1245</mn> <mrow><mo>(</mo> <mrow> <msup><mrow><mn>10</mn></mrow> <mrow><mo>-</mo> <mn>4</mn></mrow> </msup> </mrow> <mo>)</mo></mrow> <msup><mi>T</mi> <mn>2</mn></msup> <mo>+</mo> <mn>8.40705</mn> <mrow><mo>(</mo> <mrow> <msup><mrow><mn>10</mn></mrow> <mn>5</mn></msup> </mrow> <mo>)</mo></mrow> <msup><mi>T</mi> <mrow><mo>-</mo> <mn>1</mn></mrow> </msup> <mo>-</mo> <mn>5.31245</mn> <mrow><mo>(</mo> <mrow> <msup><mrow><mn>10</mn></mrow> <mn>7</mn></msup> </mrow> <mo>)</mo></mrow> <msup><mi>T</mi> <mrow><mo>-</mo> <mn>2</mn></mrow> </msup> <mo>-</mo> <mn>5453.21</mn> <mo>.</mo></mtd> </mtr> </mtable> </math> </dispformula> Values of enthalpy, heat capacity, entropy, and Gibbs free-energy function are tabulated from 298.15 to 1,200 °K.</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":"1963-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5317226/pdf/","citationCount":"0","resultStr":"{\"title\":\"Thermodynamic Properties of Magnesium Oxide and Beryllium Oxide from 298 to 1,200 °K.\",\"authors\":\"Andrew C Victor, Thomas B Douglas\",\"doi\":\"10.6028/jres.067A.034\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>As a step in developing new standards of high-temperature heat capacity and in determining accurate thermodynamic data for simple substances, the enthalpy (heat content) relative to 273 °K, of high purity fused magnesium oxide, MgO, and of sintered beryllium oxide, BeO, was measured up to 1,173 °K. A Bunsen ice calorimeter and the drop method were used. The two samples of BeO measured had surface-to-volume ratios differing by a factor of 15 or 20, yet agreed with each other closely enough to preclude appreciable error attributable to the considerable surface area. The enthalpies found for MgO are several percent higher than most previously reported values. The values are represented within their uncertainty (estimated to average ± 0.25%) by the following empirical equations (cal mole<sup>-1</sup> at <i>T</i> °K) <dispformula> <math> <mtable> <mtr><mtd><mtext>MgO</mtext> <mo>:</mo> <msubsup><mi>H</mi> <mi>T</mi> <mo>°</mo></msubsup> <mo>-</mo> <msubsup><mi>H</mi> <mrow><mn>273.15</mn></mrow> <mo>°</mo></msubsup> <mo>=</mo> <mn>10.7409</mn> <mi>T</mi> <mo>+</mo> <mn>1.2177</mn> <mrow><mo>(</mo> <mrow> <msup><mrow><mn>10</mn></mrow> <mrow><mo>-</mo> <mn>3</mn></mrow> </msup> </mrow> <mo>)</mo></mrow> <msup><mi>T</mi> <mn>2</mn></msup> <mo>-</mo> <mn>2.3183</mn> <mrow><mo>(</mo> <mrow> <msup><mrow><mn>10</mn></mrow> <mrow><mo>-</mo> <mn>7</mn></mrow> </msup> </mrow> <mo>)</mo></mrow> <msup><mi>T</mi> <mn>3</mn></msup> <mo>+</mo> <mn>2.26151</mn> <mrow><mo>(</mo> <mrow> <msup><mrow><mn>10</mn></mrow> <mn>5</mn></msup> </mrow> <mo>)</mo></mrow> <msup><mi>T</mi> <mrow><mo>-</mo> <mn>1</mn></mrow> </msup> <mo>-</mo> <mn>3847.94</mn> <mo>.</mo></mtd> </mtr> <mtr><mtd><mtext>BeO</mtext> <mo>:</mo> <msubsup><mi>H</mi> <mi>T</mi> <mo>°</mo></msubsup> <mo>-</mo> <msubsup><mi>H</mi> <mrow><mn>273.15</mn></mrow> <mo>°</mo></msubsup> <mo>=</mo> <mn>11.1084</mn> <mi>T</mi> <mo>+</mo> <mn>7.1245</mn> <mrow><mo>(</mo> <mrow> <msup><mrow><mn>10</mn></mrow> <mrow><mo>-</mo> <mn>4</mn></mrow> </msup> </mrow> <mo>)</mo></mrow> <msup><mi>T</mi> <mn>2</mn></msup> <mo>+</mo> <mn>8.40705</mn> <mrow><mo>(</mo> <mrow> <msup><mrow><mn>10</mn></mrow> <mn>5</mn></msup> </mrow> <mo>)</mo></mrow> <msup><mi>T</mi> <mrow><mo>-</mo> <mn>1</mn></mrow> </msup> <mo>-</mo> <mn>5.31245</mn> <mrow><mo>(</mo> <mrow> <msup><mrow><mn>10</mn></mrow> <mn>7</mn></msup> </mrow> <mo>)</mo></mrow> <msup><mi>T</mi> <mrow><mo>-</mo> <mn>2</mn></mrow> </msup> <mo>-</mo> <mn>5453.21</mn> <mo>.</mo></mtd> </mtr> </mtable> </math> </dispformula> Values of enthalpy, heat capacity, entropy, and Gibbs free-energy function are tabulated from 298.15 to 1,200 °K.</p>\",\"PeriodicalId\":94340,\"journal\":{\"name\":\"Journal of research of the National Bureau of Standards. 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引用次数: 0
摘要
作为制定高温热容量新标准和确定简单物质准确热力学数据的一个步骤,我们测量了高纯度熔融氧化镁(MgO)和烧结氧化铍(BeO)相对于 273 °K 的焓(热含量),最高温度为 1,173 °K。使用的是本生冰量热仪和液滴法。所测量的两个氧化铍样品的表面与体积比相差 15 或 20 倍,但它们之间的结果非常接近,足以排除因表面积较大而产生的明显误差。氧化镁的焓值比之前报告的大多数值都高出几个百分点。这些值在不确定范围内(估计平均 ± 0.25%)用以下经验公式表示(T°K 时的卡摩尔-1) 氧化镁:H T ° - H 273.15 ° = 10.7409 T + 1.2177 ( 10 - 3 ) T 2 - 2.3183 ( 10 - 7 ) T 3 + 2.26151 ( 10 5 ) T - 1 - 3847.94 。 BeO:H T ° - H 273.15 ° = 11.1084 T + 7.1245 ( 10 - 4 ) T 2 + 8.40705 ( 10 5 ) T - 1 - 5.31245 ( 10 7 ) T - 2 - 5453.21 。 焓值、热容量、熵值和吉布斯自由能函数在 298.15 至 1 200 °K 之间以表格形式列出。
Thermodynamic Properties of Magnesium Oxide and Beryllium Oxide from 298 to 1,200 °K.
As a step in developing new standards of high-temperature heat capacity and in determining accurate thermodynamic data for simple substances, the enthalpy (heat content) relative to 273 °K, of high purity fused magnesium oxide, MgO, and of sintered beryllium oxide, BeO, was measured up to 1,173 °K. A Bunsen ice calorimeter and the drop method were used. The two samples of BeO measured had surface-to-volume ratios differing by a factor of 15 or 20, yet agreed with each other closely enough to preclude appreciable error attributable to the considerable surface area. The enthalpies found for MgO are several percent higher than most previously reported values. The values are represented within their uncertainty (estimated to average ± 0.25%) by the following empirical equations (cal mole-1 at T °K) Values of enthalpy, heat capacity, entropy, and Gibbs free-energy function are tabulated from 298.15 to 1,200 °K.