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Standard molar entropy

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412: 201: 789: 141:. These contributions to the entropy are always present, because crystals always grow at a finite rate and at temperature. However, the residual entropy is often quite negligible and can be accounted for when it occurs using 937: 1068: 537: 193: 576: 407:{\displaystyle S^{\circ }=\sum _{k=1}^{N}\Delta S_{k}=\sum _{k=1}^{N}{\frac {dQ_{k}}{T}}\rightarrow \int _{0}^{T_{2}}{\frac {dS}{dT}}dT=\int _{0}^{T_{2}}{\frac {C_{p_{k}}}{T}}dT} 498:. The molar heat capacity is not constant during the experiment because it changes depending on the (increasing) temperature of the substance. Therefore, a table of values for 451: 485: 71: 668: 808: 582:. The total molar entropy is the sum of many small changes in molar entropy, where each small change can be considered a reversible process. 492: 1049: 1020: 591: 40: 1088: 90: 802:, a spontaneous reaction always results in an increase in total entropy of the system and its surroundings: 501: 1083: 1041: 799: 942:
Molar entropy is not the same for all gases. Under identical conditions, it is greater for a heavier gas.
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of pressure and any temperature of interest. These are often (but not necessarily) chosen to be the
420: 130: 456: 966: 618: 142: 49: 8: 795: 659: 488: 137:, and/or incomplete rotational quenching within the solid, as originally pointed out by 97:
is absolute. That is, an element in its standard state has a definite, nonzero value of
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The standard entropy of reaction helps determine whether the reaction will take place
784:{\displaystyle {\Delta S^{\circ }}_{rxn}=S_{products}^{\circ }-S_{reactants}^{\circ }} 1045: 1036:
Chang, Raymond; Cruickshank, Brandon (2005). "Entropy, Free Energy and Equilibrium".
1016: 961: 643: 611: 126: 102: 932:{\displaystyle (\Delta S_{total}=\Delta S_{system}+\Delta S_{surroundings})>0} 122: 578:
represents the ratio of a very small exchange of heat energy to the temperature
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K without melting, its absolute molar entropy would be the sum of a series of
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Standard entropy content of one mole of a substance under a standard state
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The heat capacity of the gas from the boiling point to room temperature.
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Table of Standard Thermodynamic Properties for Selected Substances
169:
stepwise and reversible entropy changes. The limit of this sum as
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The heat capacity of the liquid from the melting point to the
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K, then if the solid is warmed by its surroundings to 298.15
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is required to find the total molar entropy. The quantity
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of a solid substance is a perfectly ordered solid at 0
1000:(3rd ed.). Ithaca, NY: Cornell University Press. 811: 671: 545: 504: 459: 423: 204: 175: 52: 121:. However, this assumes that the material forms a ' 931: 783: 570: 531: 479: 445: 406: 187: 65: 1075: 1035: 1011:Kosanke, K. (2004). "Chemical Thermodynamics". 491:at a constant pressure of the substance in the 662:to find the standard entropy of reaction: 654:make use of the standard molar entropy of 46:The standard molar entropy at pressure = 1015:. Journal of Pyrotechnics. p. 29. 1010: 995: 642:Changes in entropy are associated with 590:The standard molar entropy of a gas at 1076: 532:{\displaystyle {\frac {C_{p_{k}}}{T}}} 188:{\displaystyle N\rightarrow \infty } 571:{\displaystyle {\frac {dQ_{k}}{T}}} 13: 874: 843: 815: 674: 239: 182: 14: 1105: 1062: 148: 41:standard temperature and pressure 91:standard enthalpies of formation 998:The Nature of the Chemical Bond 602:of one mole of the solid from 0 1029: 1004: 989: 920: 812: 298: 179: 1: 982: 594:includes contributions from: 446:{\displaystyle T_{2}=298.15K} 1042:McGraw-Hill Higher Education 800:second law of thermodynamics 585: 73:is usually given the symbol 7: 977:Third law of thermodynamics 945: 633:latent heat of vaporization 119:third law of thermodynamics 10: 1110: 480:{\displaystyle C_{p_{k}}} 131:crystallographic defects 105:. The entropy of a pure 996:Pauling, Linus (1960). 35:of pure substance at a 933: 785: 572: 533: 481: 447: 408: 275: 238: 189: 67: 25:standard molar entropy 1089:Thermodynamic entropy 1013:Pyrotechnic chemistry 967:Helmholtz free energy 934: 786: 619:latent heat of fusion 573: 534: 482: 448: 409: 255: 218: 195:becomes an integral: 190: 143:statistical mechanics 129:. This can be due to 68: 66:{\displaystyle P^{0}} 809: 669: 543: 502: 457: 421: 202: 173: 117:K, according to the 50: 1084:Chemical properties 798:. According to the 780: 738: 489:molar heat capacity 373: 322: 77:, and has units of 929: 781: 742: 703: 652:Chemical equations 648:chemical reactions 612:crystal structures 568: 529: 493:reversible process 477: 443: 404: 352: 301: 185: 109:structure can be 0 89:(J⋅mol⋅K). Unlike 63: 962:Gibbs free energy 644:phase transitions 566: 527: 417:In this example, 396: 341: 296: 113:J⋅mol⋅K only at 0 1101: 1094:Molar quantities 1056: 1055: 1033: 1027: 1026: 1008: 1002: 1001: 993: 938: 936: 935: 930: 919: 918: 870: 869: 839: 838: 790: 788: 787: 782: 779: 774: 737: 732: 699: 698: 687: 686: 685: 605: 581: 577: 575: 574: 569: 567: 562: 561: 560: 547: 538: 536: 535: 530: 528: 523: 522: 521: 520: 506: 497: 486: 484: 483: 478: 476: 475: 474: 473: 452: 450: 449: 444: 433: 432: 413: 411: 410: 405: 397: 392: 391: 390: 389: 375: 372: 371: 370: 360: 342: 340: 332: 324: 321: 320: 319: 309: 297: 292: 291: 290: 277: 274: 269: 251: 250: 237: 232: 214: 213: 194: 192: 191: 186: 168: 164: 160: 127:residual entropy 116: 112: 103:room temperature 100: 96: 76: 72: 70: 69: 64: 62: 61: 1109: 1108: 1104: 1103: 1102: 1100: 1099: 1098: 1074: 1073: 1065: 1060: 1059: 1052: 1044:. p. 765. 1034: 1030: 1023: 1009: 1005: 994: 990: 985: 948: 881: 877: 850: 846: 822: 818: 810: 807: 806: 775: 746: 733: 707: 688: 681: 677: 673: 672: 670: 667: 666: 603: 588: 579: 556: 552: 548: 546: 544: 541: 540: 516: 512: 511: 507: 505: 503: 500: 499: 495: 469: 465: 464: 460: 458: 455: 454: 428: 424: 422: 419: 418: 385: 381: 380: 376: 374: 366: 362: 361: 356: 333: 325: 323: 315: 311: 310: 305: 286: 282: 278: 276: 270: 259: 246: 242: 233: 222: 209: 205: 203: 200: 199: 174: 171: 170: 166: 162: 158: 151: 123:perfect crystal 114: 110: 98: 94: 93:, the value of 74: 57: 53: 51: 48: 47: 31:content of one 17: 12: 11: 5: 1107: 1097: 1096: 1091: 1086: 1072: 1071: 1064: 1063:External links 1061: 1058: 1057: 1050: 1028: 1021: 1003: 987: 986: 984: 981: 980: 979: 974: 972:Standard state 969: 964: 959: 954: 947: 944: 940: 939: 928: 925: 922: 917: 914: 911: 908: 905: 902: 899: 896: 893: 890: 887: 884: 880: 876: 873: 868: 865: 862: 859: 856: 853: 849: 845: 842: 837: 834: 831: 828: 825: 821: 817: 814: 792: 791: 778: 773: 770: 767: 764: 761: 758: 755: 752: 749: 745: 741: 736: 731: 728: 725: 722: 719: 716: 713: 710: 706: 702: 697: 694: 691: 684: 680: 676: 640: 639: 636: 635:of the liquid. 629: 622: 615: 587: 584: 565: 559: 555: 551: 526: 519: 515: 510: 472: 468: 463: 442: 439: 436: 431: 427: 415: 414: 403: 400: 395: 388: 384: 379: 369: 365: 359: 355: 351: 348: 345: 339: 336: 331: 328: 318: 314: 308: 304: 300: 295: 289: 285: 281: 273: 268: 265: 262: 258: 254: 249: 245: 241: 236: 231: 228: 225: 221: 217: 212: 208: 184: 181: 178: 150: 149:Thermodynamics 147: 125:' without any 60: 56: 37:standard state 15: 9: 6: 4: 3: 2: 1106: 1095: 1092: 1090: 1087: 1085: 1082: 1081: 1079: 1070: 1067: 1066: 1053: 1051:0-07-251264-4 1047: 1043: 1039: 1032: 1024: 1022:1-889526-15-0 1018: 1014: 1007: 999: 992: 988: 978: 975: 973: 970: 968: 965: 963: 960: 958: 955: 953: 950: 949: 943: 926: 923: 915: 912: 909: 906: 903: 900: 897: 894: 891: 888: 885: 882: 878: 871: 866: 863: 860: 857: 854: 851: 847: 840: 835: 832: 829: 826: 823: 819: 805: 804: 803: 801: 797: 796:spontaneously 776: 771: 768: 765: 762: 759: 756: 753: 750: 747: 743: 739: 734: 729: 726: 723: 720: 717: 714: 711: 708: 704: 700: 695: 692: 689: 682: 678: 665: 664: 663: 661: 657: 653: 649: 645: 637: 634: 630: 627: 626:boiling point 623: 621:of the solid. 620: 616: 613: 609: 608:melting point 601: 600:heat capacity 597: 596: 595: 593: 583: 563: 557: 553: 549: 524: 517: 513: 508: 494: 490: 470: 466: 461: 440: 437: 434: 429: 425: 401: 398: 393: 386: 382: 377: 367: 363: 357: 353: 349: 346: 343: 337: 334: 329: 326: 316: 312: 306: 302: 293: 287: 283: 279: 271: 266: 263: 260: 256: 252: 247: 243: 234: 229: 226: 223: 219: 215: 210: 206: 198: 197: 196: 176: 156: 146: 144: 140: 139:Linus Pauling 136: 132: 128: 124: 120: 108: 104: 92: 88: 84: 80: 58: 54: 44: 42: 38: 34: 30: 26: 22: 1037: 1031: 1012: 1006: 997: 991: 941: 793: 641: 589: 416: 152: 135:dislocations 45: 24: 18: 107:crystalline 1078:Categories 983:References 1038:Chemistry 875:Δ 844:Δ 816:Δ 777:∘ 740:− 735:∘ 683:∘ 675:Δ 656:reactants 606:K to the 586:Chemistry 354:∫ 303:∫ 299:→ 257:∑ 240:Δ 220:∑ 211:∘ 183:∞ 180:→ 21:chemistry 946:See also 660:products 952:Entropy 487:is the 29:entropy 27:is the 1048:  1019:  604:  438:298.15 163:  159:  115:  111:  87:kelvin 79:joules 23:, the 153:If a 1046:ISBN 1017:ISBN 957:Heat 924:> 658:and 646:and 631:The 617:The 598:The 453:and 155:mole 85:per 83:mole 81:per 33:mole 592:STP 145:. 101:at 19:In 1080:: 1040:. 650:. 614:). 133:, 95:S° 75:S° 43:. 1054:. 1025:. 927:0 921:) 916:s 913:g 910:n 907:i 904:d 901:n 898:u 895:o 892:r 889:r 886:u 883:s 879:S 872:+ 867:m 864:e 861:t 858:s 855:y 852:s 848:S 841:= 836:l 833:a 830:t 827:o 824:t 820:S 813:( 772:s 769:t 766:n 763:a 760:t 757:c 754:a 751:e 748:r 744:S 730:s 727:t 724:c 721:u 718:d 715:o 712:r 709:p 705:S 701:= 696:n 693:x 690:r 679:S 628:. 580:T 564:T 558:k 554:Q 550:d 525:T 518:k 514:p 509:C 496:k 471:k 467:p 462:C 441:K 435:= 430:2 426:T 402:T 399:d 394:T 387:k 383:p 378:C 368:2 364:T 358:0 350:= 347:T 344:d 338:T 335:d 330:S 327:d 317:2 313:T 307:0 294:T 288:k 284:Q 280:d 272:N 267:1 264:= 261:k 253:= 248:k 244:S 235:N 230:1 227:= 224:k 216:= 207:S 177:N 167:N 99:S 59:0 55:P

Index

chemistry
entropy
mole
standard state
standard temperature and pressure
joules
mole
kelvin
standard enthalpies of formation
room temperature
crystalline
third law of thermodynamics
perfect crystal
residual entropy
crystallographic defects
dislocations
Linus Pauling
statistical mechanics
mole
molar heat capacity
reversible process
STP
heat capacity
melting point
crystal structures
latent heat of fusion
boiling point
latent heat of vaporization
phase transitions
chemical reactions

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