598:, be coalesced into a single new final isolated thermodynamic system. If the initial systems differ in chemical constitution, then the eventual thermodynamic equilibrium of the final system can be the result of chemical reaction. Alternatively, an isolated thermodynamic system, in the absence of some catalyst, can be in a metastable equilibrium; introduction of a catalyst, or some other thermodynamic operation, such as release of a spark, can trigger a chemical reaction. The chemical reaction will, in general, transform some
606:. If the joint system is kept isolated, then its internal energy remains unchanged. Such thermal energy manifests itself, however, in changes in the non-chemical state variables (such as temperature, pressure, volume) of the joint systems, as well as the changes in the mole numbers of the chemical constituents that describe the chemical reaction.
1920:
492:
609:
Internal energy is defined with respect to some standard state. Subject to suitable thermodynamic operations, the chemical constituents of the final system can be brought to their respective standard states, along with transfer of energy as heat or through thermodynamic work, which can be measured or
1675:
By convention, the enthalpy of each element in its standard state is assigned a value of zero. If pure preparations of compounds or ions are not possible, then special further conventions are defined. Regardless, if each reactant and product can be prepared in its respective standard state, then the
996:
At constant pressure on the other hand, the system is either kept open to the atmosphere or confined within a container on which a constant external pressure is exerted and under these conditions the volume of the system changes. The thermal change at a constant pressure not only involves the change
789:
The magnitudes of the heat effects in these two conditions are different. In the first case the volume of the system is kept constant during the course of the measurement by carrying out the reaction in a closed and rigid container, and as there is no change in the volume no work is involved. From
2190:
for a solution of ideal gases is exactly zero; the same is true for a reaction where the reactants and products are pure, unmixed components. Contributions to reaction enthalpies due to concentration variations for solutes in solution generally must be experimentally determined on a case by case
2180:
217:
539:
For ions in aqueous solution, the standard state is often chosen such that the aqueous H ion at a concentration of exactly 1 mole/liter has a standard enthalpy of formation equal to zero, which makes possible the tabulation of standard enthalpies for cations and anions at the same standard
1709:
1516:
1312:
303:
2578:, which states that the enthalpy change is the same for a chemical reaction which occurs as a single reaction or in several steps. If the enthalpies for each step can be measured, then their sum gives the enthalpy of the overall single reaction.
618:
The standard enthalpy of a reaction is defined so as to depend simply upon the standard conditions that are specified for it, not simply on the conditions under which the reactions actually occur. There are two general conditions under which
535:
Standard states can be defined at any temperature and pressure, so both the standard temperature and pressure must always be specified. Most values of standard thermochemical data are tabulated at either (25°C, 1 bar) or (25°C, 1 atm).
2482:
610:
calculated from measurements of non-chemical state variables. Accordingly, the calculation of standard enthalpy of reaction is the most established way of quantifying the conversion of chemical potential energy into thermal energy.
2585:
for the bonds which are broken and formed in the reaction of interest. This method is only approximate, however, because a reported bond energy is only an average value for different molecules with bonds between the same elements.
2043:
2056:
94:
2573:
It is also possible to evaluate the enthalpy of one reaction from the enthalpies of a number of other reactions whose sum is the reaction of interest, and these not need be formation reactions. This method is based on
532:, which has been determined for a vast number of substances, is the change of enthalpy during the formation of 1 mole of the substance from its constituent elements, with all substances in their standard states.
2256:
is the enthalpy change when one mole of any compound is formed from its constituent elements in their standard states. The enthalpy of formation of one mole of ethane gas refers to the reaction 2 C (graphite) +
1670:
988:
1676:
contribution of each species is equal to its molar enthalpy of formation multiplied by its stoichiometric coefficient in the reaction, and the enthalpy of reaction at constant (standard) pressure
255:
67:
887:
The thermal change that occurs in a chemical reaction is only due to the difference between the sum of internal energy of the products and the sum of the internal energy of reactants. We have
2568:
1915:{\displaystyle Q_{P^{\ominus }}=\Delta _{\text{rxn}}H^{\ominus }=\sum _{products,~p}\nu _{p}\Delta _{\text{f}}H_{p}^{\ominus }-\sum _{reactants,~r}\nu _{r}\Delta _{\text{f}}H_{r}^{\ominus }}
2186:
Pressure variation effects and corrections due to mixing are generally minimal unless a reaction involves non-ideal gases and/or solutes, or is carried out at extremely high pressures. The
295:
2343:
There are several methods of determining the values of reaction enthalpies, involving either measurements on the reaction of interest or calculations from data for related reactions.
1320:
1112:
1953:
2531:
1123:
487:{\displaystyle \Delta H_{\text{reaction}}^{\ominus }=\sum _{products,~p}\nu _{p}\Delta _{\text{f}}H_{p}^{\ominus }-\sum _{reactants,~r}\nu _{r}\Delta _{\text{f}}H_{r}^{\ominus }}
859:
744:
661:
1701:
1033:
823:
882:
522:
580:
1554:
779:
2396:
2374:, in which the heat released by combustion at high temperature is lost to the surroundings as the system returns to its initial temperature. Since enthalpy is a
1057:
701:
681:
993:
This also signifies that the amount of heat absorbed at constant volume could be identified with the change in the thermodynamic quantity internal energy.
1977:
997:
in the internal energy of the system but also the work performed either in expansion or contraction of the system. In general the first law requires that
2175:{\displaystyle \Delta H^{\circ }\!\left(T\right)=\Delta H^{\circ }\!\left(T^{\circ }\right)+\int _{T^{\circ }}^{T}\Delta C_{P}^{\circ }\,\mathrm {d} T}
212:{\displaystyle \nu _{\text{A}}{\text{A}}+\nu _{\,{\text{B}}}{\text{B}}~+~...\rightarrow \nu _{\,{\text{X}}}{\text{X}}+\nu _{\text{Y}}{\text{Y}}~+~...}
548:. However, there are other common choices in certain fields, including a standard concentration for H of exactly 1 mole/(kg solvent) (widely used in
586:). For this reason it is important to note which standard concentration value is being used when consulting tables of enthalpies of formation.
2049:
Integration of this equation permits the evaluation of the heat of reaction at one temperature from measurements at another temperature.
1562:
2310:
is the change in enthalpy that occurs when an acid and base undergo a neutralization reaction to form one mole of water. For example in
893:
525:
2195:
since no change in the solution's average intermolecular forces as a function of concentration is possible in an ideal solution.
594:
Two initial thermodynamic systems, each isolated in their separate states of internal thermodynamic equilibrium, can, by a
225:
37:
17:
1964:
2307:
2277:
2536:
2771:
2746:
2697:
2669:
2637:
2612:
2346:
For reactions which go rapidly to completion, it is often possible to measure the heat of reaction directly using a
263:
1511:{\displaystyle Q_{P}=\sum \left(U_{products}+PV_{products}\right)-\sum \left(U_{reactants}+PV_{reactants}\right)}
529:
258:
1069:
1307:{\displaystyle Q_{P}=\sum U_{products}-\sum U_{reactants}+P\left(\sum V_{products}-\sum V_{reactants}\right)}
1967:, which states that the temperature derivative of ΔH for a chemical reaction is given by the difference in
1928:
2495:
861:; this implies that the heat of reaction at constant volume is equal to the change in the internal energy
541:
2280:
compound reacts with an excess of hydrogen to become fully saturated. The hydrogenation of one mole of
1925:
As shown above, at constant pressure the heat of the reaction is exactly equal to the enthalpy change,
825:, where W is the work done by the system. When only expansion work is possible for a process we have
828:
713:
630:
2840:
2378:, its value is the same for any path between given initial and final states, so that the measured Δ
1679:
1003:
793:
2845:
2390:
595:
2389:
can be determined as a function of temperature. The enthalpy of reaction is then found from the
2226:) to form carbon dioxide and liquid water. For example, the standard enthalpy of combustion of
864:
500:
2477:{\displaystyle \Delta _{\text{rxn}}H^{\ominus }={RT^{2}}{\frac {d}{dT}}\ln K_{\mathrm {eq} }}
555:
1524:
749:
2386:
2371:
1060:
549:
1117:
Assuming that the change in state variables is due solely to a chemical reaction, we have
8:
2319:
2215:
2187:
1042:
686:
666:
2835:
2767:
2742:
2693:
2665:
2633:
2608:
2315:
2253:
2038:{\displaystyle \left({\frac {\partial \Delta H}{\partial T}}\right)_{p}=\Delta C_{p}}
70:
613:
2712:
2355:
2311:
545:
81:. The value can be approximately interpreted in terms of the total of the chemical
2218:
is the enthalpy change when one mole of an organic compound reacts with molecular
704:
620:
599:
2727:
and de Paula J., "Atkins' Physical
Chemistry" (8th edn, W.H. Freeman 2006), p.56
2375:
2363:
2208:
2192:
603:
78:
2829:
2575:
2350:. One large class of reactions for which such measurements are common is the
2273:
1968:
2724:
2489:
2485:
583:
2582:
2382:
is the same as if the temperature stayed constant during the combustion.
2347:
82:
27:
Enthalpy difference due to chemical reaction, reduced to standard states
2351:
1963:
The variation of the enthalpy of reaction with temperature is given by
2737:
Petrucci, Ralph H.; Harwood, William S.; Herring, F. Geoffrey (2002).
2690:
Physical
Chemistry: Principles and Applications in Biological Sciences
2662:
Physical
Chemistry: Principles and Applications in Biological Sciences
2630:
Physical
Chemistry: Principles and Applications in Biological Sciences
2603:
Petrucci, Ralph H.; Harwood, William S.; Herring, F. Geoffrey (2002).
2281:
2715:
and Meiser J.H., "Physical
Chemistry" (Benjamin/Cummings 1982), p.62
1665:{\displaystyle Q_{P}=\sum H_{products}-\sum H_{reactants}=\Delta H}
782:
74:
2484:. A closely related technique is the use of an electroanalytical
614:
Enthalpy of reaction for standard conditions defined and measured
540:
concentration. This convention is consistent with the use of the
73:
is the difference between total product and total reactant molar
297:
values of the reactants and products by the following equation:
2276:
is defined as the enthalpy change observed when one mole of an
2227:
2219:
2492:
for certain reactions as a function of temperature, yielding
2284:
yields ethane as a product and is described by the equation C
1703:
and constant temperature (usually 298 K) may be written as
983:{\displaystyle \Delta U=\sum U_{products}-\sum U_{reactants}}
2688:
Tinoco, Ignacio Jr.; Sauer, Kenneth; Wang, James C. (1995).
2660:
Tinoco, Ignacio Jr.; Sauer, Kenneth; Wang, James C. (1995).
2628:
Tinoco, Ignacio Jr.; Sauer, Kenneth; Wang, James C. (1995).
2370:
O). The heat of combustion can be measured with a so-called
1958:
1971:(at constant pressure) between products and reactants:
2736:
2602:
2581:
Finally the reaction enthalpy may be estimated using
2539:
2498:
2399:
2207:
implies that all reactants and products are in their
2059:
1980:
1931:
1712:
1682:
1565:
1527:
1323:
1126:
1072:
1045:
1006:
896:
867:
831:
796:
752:
716:
689:
669:
633:
558:
503:
306:
266:
250:{\displaystyle \Delta H_{\text{reaction}}^{\ominus }}
228:
97:
62:{\displaystyle \Delta H_{\text{reaction}}^{\ominus }}
40:
2338:
2562:
2525:
2476:
2174:
2037:
1947:
1914:
1695:
1664:
1548:
1510:
1306:
1106:
1051:
1027:
982:
876:
853:
817:
773:
738:
695:
675:
655:
574:
516:
486:
289:
249:
211:
61:
2741:(8th ed.). Prentice Hall. pp. 227–229.
2101:
2073:
2827:
2795:
2563:{\displaystyle \Delta _{\text{rxn}}H^{\ominus }}
2687:
2659:
2627:
290:{\displaystyle \Delta _{\text{f}}H^{\ominus }}
2800:. University Science Books. pp. 356–360.
2796:Chang, Raymond; Thoman, Jr., John W. (2014).
2766:. Pearson Benjamin Cummings. pp. 72–73.
2314:, the standard enthalpy of neutralization of
2819:Petrucci, Harwood and Herring, pages 422–423
2810:Petrucci, Harwood and Herring, pages 241–243
2798:Physical Chemistry for the Chemical Sciences
2632:(3rd ed.). Prentice-Hall. p. 125.
2607:(8th ed.). Prentice Hall. p. 247.
2322:refers to the reaction HCl (aq) + 1/2 Mg(OH)
710:(b) Constant pressure and temperature: heat
2692:(3rd ed.). Prentice-Hall. p. 48.
2664:(3rd ed.). Prentice-Hall. p. 44.
2683:
2681:
2655:
2653:
2651:
2649:
1521:As enthalpy or heat content is defined by
627:(a) Constant volume and temperature: heat
2761:
2163:
160:
121:
2385:For reactions which are incomplete, the
1107:{\displaystyle Q_{P}=\Delta U+P\Delta V}
2678:
2646:
14:
2828:
1959:Variation with temperature or pressure
2191:basis, but would be exactly zero for
1948:{\displaystyle \Delta _{\text{rxn}}H}
77:, calculated for substances in their
2762:Engel, Thomas; Reid, Philip (2006).
2526:{\displaystyle K_{\mathrm {eq} }(T)}
2358:by reaction with molecular oxygen (O
2488:, which can be used to measure the
2308:Standard enthalpy of neutralization
85:for bonds broken and bonds formed.
24:
2541:
2508:
2505:
2468:
2465:
2401:
2165:
2145:
2088:
2060:
2022:
2000:
1992:
1989:
1965:Kirchhoff's Law of Thermochemistry
1933:
1888:
1807:
1734:
1656:
1098:
1086:
1013:
897:
868:
832:
797:
730:
647:
528:of each product and reactant. The
460:
379:
307:
268:
229:
222:the standard enthalpy of reaction
41:
25:
2857:
2339:Evaluation of reaction enthalpies
790:the first law of thermodynamics,
2198:
623:measurements are actually made.
88:For a generic chemical reaction
2813:
2804:
2789:
2216:Standard enthalpy of combustion
589:
2780:
2755:
2730:
2718:
2706:
2621:
2596:
2520:
2514:
2254:Standard enthalpy of formation
854:{\displaystyle \Delta U=Q_{V}}
739:{\displaystyle Q_{P}=\Delta H}
656:{\displaystyle Q_{V}=\Delta U}
530:standard enthalpy of formation
259:standard enthalpy of formation
152:
13:
1:
2589:
1063:, then at constant pressure
582:mole/L (used in the field of
32:standard enthalpy of reaction
2230:gas refers to the reaction C
1696:{\displaystyle P^{\ominus }}
1028:{\displaystyle Q=\Delta U+W}
818:{\displaystyle \Delta U=Q-W}
7:
542:standard hydrogen electrode
526:stoichiometric coefficients
10:
2862:
1955:, of the reacting system.
600:chemical potential energy
884:of the reacting system.
877:{\displaystyle \Delta U}
517:{\displaystyle \nu _{i}}
596:thermodynamic operation
575:{\displaystyle 10^{-7}}
2564:
2527:
2478:
2203:In each case the word
2176:
2039:
1949:
1916:
1697:
1666:
1550:
1549:{\displaystyle H=U+PV}
1512:
1308:
1108:
1053:
1029:
984:
878:
855:
819:
775:
774:{\displaystyle H=U+PV}
740:
697:
683:(sometimes written as
677:
657:
576:
518:
488:
291:
251:
213:
63:
2565:
2528:
2479:
2272:Standard enthalpy of
2177:
2040:
1950:
1917:
1698:
1667:
1551:
1513:
1309:
1109:
1054:
1030:
985:
879:
856:
820:
776:
741:
698:
678:
658:
577:
519:
489:
292:
252:
214:
64:
2537:
2496:
2397:
2391:van 't Hoff equation
2387:equilibrium constant
2057:
1978:
1929:
1710:
1680:
1563:
1525:
1321:
1124:
1070:
1061:pressure–volume work
1043:
1004:
894:
865:
829:
794:
750:
714:
687:
667:
631:
556:
550:chemical engineering
501:
304:
264:
226:
95:
38:
18:Enthalpy of reaction
2786:Engel and Reid p.65
2320:magnesium hydroxide
2162:
2144:
1911:
1830:
483:
402:
324:
246:
58:
2764:Physical Chemistry
2560:
2523:
2474:
2188:enthalpy of mixing
2172:
2148:
2123:
2035:
1945:
1912:
1897:
1876:
1816:
1795:
1693:
1662:
1546:
1508:
1304:
1104:
1049:
1025:
980:
874:
851:
815:
771:
736:
693:
673:
653:
572:
514:
497:In this equation,
484:
469:
448:
388:
367:
310:
287:
257:is related to the
247:
232:
209:
59:
44:
2739:General Chemistry
2605:General Chemistry
2547:
2451:
2407:
2356:organic compounds
2316:hydrochloric acid
2007:
1939:
1894:
1871:
1834:
1813:
1790:
1756:
1740:
1052:{\displaystyle W}
696:{\displaystyle E}
676:{\displaystyle U}
466:
443:
406:
385:
362:
328:
317:
274:
239:
199:
193:
189:
183:
171:
164:
142:
136:
132:
125:
111:
105:
71:chemical reaction
51:
16:(Redirected from
2853:
2820:
2817:
2811:
2808:
2802:
2801:
2793:
2787:
2784:
2778:
2777:
2759:
2753:
2752:
2734:
2728:
2722:
2716:
2710:
2704:
2703:
2685:
2676:
2675:
2657:
2644:
2643:
2625:
2619:
2618:
2600:
2569:
2567:
2566:
2561:
2559:
2558:
2549:
2548:
2545:
2532:
2530:
2529:
2524:
2513:
2512:
2511:
2483:
2481:
2480:
2475:
2473:
2472:
2471:
2452:
2450:
2439:
2437:
2436:
2435:
2419:
2418:
2409:
2408:
2405:
2372:bomb calorimeter
2312:aqueous solution
2181:
2179:
2178:
2173:
2168:
2161:
2156:
2143:
2138:
2137:
2136:
2119:
2115:
2114:
2100:
2099:
2084:
2072:
2071:
2044:
2042:
2041:
2036:
2034:
2033:
2018:
2017:
2012:
2008:
2006:
1998:
1987:
1954:
1952:
1951:
1946:
1941:
1940:
1937:
1921:
1919:
1918:
1913:
1910:
1905:
1896:
1895:
1892:
1886:
1885:
1875:
1869:
1829:
1824:
1815:
1814:
1811:
1805:
1804:
1794:
1788:
1752:
1751:
1742:
1741:
1738:
1729:
1728:
1727:
1726:
1702:
1700:
1699:
1694:
1692:
1691:
1671:
1669:
1668:
1663:
1652:
1651:
1612:
1611:
1575:
1574:
1555:
1553:
1552:
1547:
1517:
1515:
1514:
1509:
1507:
1503:
1502:
1501:
1462:
1461:
1417:
1413:
1412:
1411:
1375:
1374:
1333:
1332:
1313:
1311:
1310:
1305:
1303:
1299:
1298:
1297:
1258:
1257:
1213:
1212:
1173:
1172:
1136:
1135:
1113:
1111:
1110:
1105:
1082:
1081:
1058:
1056:
1055:
1050:
1034:
1032:
1031:
1026:
989:
987:
986:
981:
979:
978:
939:
938:
883:
881:
880:
875:
860:
858:
857:
852:
850:
849:
824:
822:
821:
816:
780:
778:
777:
772:
745:
743:
742:
737:
726:
725:
702:
700:
699:
694:
682:
680:
679:
674:
662:
660:
659:
654:
643:
642:
581:
579:
578:
573:
571:
570:
546:electrochemistry
544:in the field of
523:
521:
520:
515:
513:
512:
493:
491:
490:
485:
482:
477:
468:
467:
464:
458:
457:
447:
441:
401:
396:
387:
386:
383:
377:
376:
366:
360:
323:
318:
315:
296:
294:
293:
288:
286:
285:
276:
275:
272:
256:
254:
253:
248:
245:
240:
237:
218:
216:
215:
210:
197:
191:
190:
187:
185:
184:
181:
172:
169:
167:
166:
165:
162:
140:
134:
133:
130:
128:
127:
126:
123:
112:
109:
107:
106:
103:
68:
66:
65:
60:
57:
52:
49:
21:
2861:
2860:
2856:
2855:
2854:
2852:
2851:
2850:
2841:Thermochemistry
2826:
2825:
2824:
2823:
2818:
2814:
2809:
2805:
2794:
2790:
2785:
2781:
2774:
2760:
2756:
2749:
2735:
2731:
2723:
2719:
2711:
2707:
2700:
2686:
2679:
2672:
2658:
2647:
2640:
2626:
2622:
2615:
2601:
2597:
2592:
2554:
2550:
2544:
2540:
2538:
2535:
2534:
2504:
2503:
2499:
2497:
2494:
2493:
2464:
2463:
2459:
2443:
2438:
2431:
2427:
2423:
2414:
2410:
2404:
2400:
2398:
2395:
2394:
2369:
2361:
2341:
2333:
2329:
2325:
2303:
2299:
2295:
2291:
2287:
2268:
2264:
2260:
2249:
2245:
2241:
2237:
2233:
2225:
2209:standard states
2201:
2193:ideal solutions
2164:
2157:
2152:
2139:
2132:
2128:
2127:
2110:
2106:
2102:
2095:
2091:
2074:
2067:
2063:
2058:
2055:
2054:
2029:
2025:
2013:
1999:
1988:
1986:
1982:
1981:
1979:
1976:
1975:
1961:
1936:
1932:
1930:
1927:
1926:
1906:
1901:
1891:
1887:
1881:
1877:
1838:
1825:
1820:
1810:
1806:
1800:
1796:
1760:
1747:
1743:
1737:
1733:
1722:
1718:
1717:
1713:
1711:
1708:
1707:
1687:
1683:
1681:
1678:
1677:
1623:
1619:
1586:
1582:
1570:
1566:
1564:
1561:
1560:
1526:
1523:
1522:
1473:
1469:
1433:
1429:
1428:
1424:
1386:
1382:
1349:
1345:
1344:
1340:
1328:
1324:
1322:
1319:
1318:
1269:
1265:
1232:
1228:
1224:
1220:
1184:
1180:
1147:
1143:
1131:
1127:
1125:
1122:
1121:
1077:
1073:
1071:
1068:
1067:
1044:
1041:
1040:
1005:
1002:
1001:
950:
946:
913:
909:
895:
892:
891:
866:
863:
862:
845:
841:
830:
827:
826:
795:
792:
791:
751:
748:
747:
721:
717:
715:
712:
711:
705:internal energy
688:
685:
684:
668:
665:
664:
638:
634:
632:
629:
628:
616:
592:
563:
559:
557:
554:
553:
508:
504:
502:
499:
498:
478:
473:
463:
459:
453:
449:
410:
397:
392:
382:
378:
372:
368:
332:
319:
314:
305:
302:
301:
281:
277:
271:
267:
265:
262:
261:
241:
236:
227:
224:
223:
186:
180:
176:
168:
161:
159:
155:
129:
122:
120:
116:
108:
102:
98:
96:
93:
92:
79:standard states
53:
48:
39:
36:
35:
28:
23:
22:
15:
12:
11:
5:
2859:
2849:
2848:
2846:Thermodynamics
2843:
2838:
2822:
2821:
2812:
2803:
2788:
2779:
2772:
2754:
2747:
2729:
2717:
2705:
2698:
2677:
2670:
2645:
2638:
2620:
2613:
2594:
2593:
2591:
2588:
2557:
2553:
2543:
2522:
2519:
2516:
2510:
2507:
2502:
2470:
2467:
2462:
2458:
2455:
2449:
2446:
2442:
2434:
2430:
2426:
2422:
2417:
2413:
2403:
2376:state function
2367:
2364:carbon dioxide
2359:
2340:
2337:
2336:
2335:
2331:
2327:
2323:
2305:
2301:
2297:
2293:
2289:
2285:
2270:
2266:
2262:
2258:
2251:
2247:
2243:
2239:
2235:
2231:
2223:
2200:
2197:
2184:
2183:
2171:
2167:
2160:
2155:
2151:
2147:
2142:
2135:
2131:
2126:
2122:
2118:
2113:
2109:
2105:
2098:
2094:
2090:
2087:
2083:
2080:
2077:
2070:
2066:
2062:
2047:
2046:
2032:
2028:
2024:
2021:
2016:
2011:
2005:
2002:
1997:
1994:
1991:
1985:
1960:
1957:
1944:
1935:
1923:
1922:
1909:
1904:
1900:
1890:
1884:
1880:
1874:
1868:
1865:
1862:
1859:
1856:
1853:
1850:
1847:
1844:
1841:
1837:
1833:
1828:
1823:
1819:
1809:
1803:
1799:
1793:
1787:
1784:
1781:
1778:
1775:
1772:
1769:
1766:
1763:
1759:
1755:
1750:
1746:
1736:
1732:
1725:
1721:
1716:
1690:
1686:
1673:
1672:
1661:
1658:
1655:
1650:
1647:
1644:
1641:
1638:
1635:
1632:
1629:
1626:
1622:
1618:
1615:
1610:
1607:
1604:
1601:
1598:
1595:
1592:
1589:
1585:
1581:
1578:
1573:
1569:
1545:
1542:
1539:
1536:
1533:
1530:
1519:
1518:
1506:
1500:
1497:
1494:
1491:
1488:
1485:
1482:
1479:
1476:
1472:
1468:
1465:
1460:
1457:
1454:
1451:
1448:
1445:
1442:
1439:
1436:
1432:
1427:
1423:
1420:
1416:
1410:
1407:
1404:
1401:
1398:
1395:
1392:
1389:
1385:
1381:
1378:
1373:
1370:
1367:
1364:
1361:
1358:
1355:
1352:
1348:
1343:
1339:
1336:
1331:
1327:
1315:
1314:
1302:
1296:
1293:
1290:
1287:
1284:
1281:
1278:
1275:
1272:
1268:
1264:
1261:
1256:
1253:
1250:
1247:
1244:
1241:
1238:
1235:
1231:
1227:
1223:
1219:
1216:
1211:
1208:
1205:
1202:
1199:
1196:
1193:
1190:
1187:
1183:
1179:
1176:
1171:
1168:
1165:
1162:
1159:
1156:
1153:
1150:
1146:
1142:
1139:
1134:
1130:
1115:
1114:
1103:
1100:
1097:
1094:
1091:
1088:
1085:
1080:
1076:
1048:
1037:
1036:
1024:
1021:
1018:
1015:
1012:
1009:
991:
990:
977:
974:
971:
968:
965:
962:
959:
956:
953:
949:
945:
942:
937:
934:
931:
928:
925:
922:
919:
916:
912:
908:
905:
902:
899:
873:
870:
848:
844:
840:
837:
834:
814:
811:
808:
805:
802:
799:
787:
786:
770:
767:
764:
761:
758:
755:
735:
732:
729:
724:
720:
708:
692:
672:
652:
649:
646:
641:
637:
621:thermochemical
615:
612:
604:thermal energy
591:
588:
569:
566:
562:
511:
507:
495:
494:
481:
476:
472:
462:
456:
452:
446:
440:
437:
434:
431:
428:
425:
422:
419:
416:
413:
409:
405:
400:
395:
391:
381:
375:
371:
365:
359:
356:
353:
350:
347:
344:
341:
338:
335:
331:
327:
322:
313:
309:
284:
280:
270:
244:
235:
231:
220:
219:
208:
205:
202:
196:
179:
175:
158:
154:
151:
148:
145:
139:
119:
115:
101:
56:
47:
43:
26:
9:
6:
4:
3:
2:
2858:
2847:
2844:
2842:
2839:
2837:
2834:
2833:
2831:
2816:
2807:
2799:
2792:
2783:
2775:
2773:0-8053-3842-X
2769:
2765:
2758:
2750:
2748:0-13-014329-4
2744:
2740:
2733:
2726:
2721:
2714:
2709:
2701:
2699:0-13-186545-5
2695:
2691:
2684:
2682:
2673:
2671:0-13-186545-5
2667:
2663:
2656:
2654:
2652:
2650:
2641:
2639:0-13-186545-5
2635:
2631:
2624:
2616:
2614:0-13-014329-4
2610:
2606:
2599:
2595:
2587:
2584:
2583:bond energies
2579:
2577:
2571:
2555:
2551:
2517:
2500:
2491:
2487:
2460:
2456:
2453:
2447:
2444:
2440:
2432:
2428:
2424:
2420:
2415:
2411:
2392:
2388:
2383:
2381:
2377:
2373:
2365:
2357:
2353:
2349:
2344:
2321:
2318:and the base
2317:
2313:
2309:
2306:
2283:
2279:
2275:
2274:hydrogenation
2271:
2255:
2252:
2238:(g) + (7/2) O
2229:
2221:
2217:
2214:
2213:
2212:
2210:
2206:
2199:Subcategories
2196:
2194:
2189:
2182:
2169:
2158:
2153:
2149:
2140:
2133:
2129:
2124:
2120:
2116:
2111:
2107:
2103:
2096:
2092:
2085:
2081:
2078:
2075:
2068:
2064:
2052:
2051:
2050:
2030:
2026:
2019:
2014:
2009:
2003:
1995:
1983:
1974:
1973:
1972:
1970:
1969:heat capacity
1966:
1956:
1942:
1907:
1902:
1898:
1882:
1878:
1872:
1866:
1863:
1860:
1857:
1854:
1851:
1848:
1845:
1842:
1839:
1835:
1831:
1826:
1821:
1817:
1801:
1797:
1791:
1785:
1782:
1779:
1776:
1773:
1770:
1767:
1764:
1761:
1757:
1753:
1748:
1744:
1730:
1723:
1719:
1714:
1706:
1705:
1704:
1688:
1684:
1659:
1653:
1648:
1645:
1642:
1639:
1636:
1633:
1630:
1627:
1624:
1620:
1616:
1613:
1608:
1605:
1602:
1599:
1596:
1593:
1590:
1587:
1583:
1579:
1576:
1571:
1567:
1559:
1558:
1557:
1543:
1540:
1537:
1534:
1531:
1528:
1504:
1498:
1495:
1492:
1489:
1486:
1483:
1480:
1477:
1474:
1470:
1466:
1463:
1458:
1455:
1452:
1449:
1446:
1443:
1440:
1437:
1434:
1430:
1425:
1421:
1418:
1414:
1408:
1405:
1402:
1399:
1396:
1393:
1390:
1387:
1383:
1379:
1376:
1371:
1368:
1365:
1362:
1359:
1356:
1353:
1350:
1346:
1341:
1337:
1334:
1329:
1325:
1317:
1316:
1300:
1294:
1291:
1288:
1285:
1282:
1279:
1276:
1273:
1270:
1266:
1262:
1259:
1254:
1251:
1248:
1245:
1242:
1239:
1236:
1233:
1229:
1225:
1221:
1217:
1214:
1209:
1206:
1203:
1200:
1197:
1194:
1191:
1188:
1185:
1181:
1177:
1174:
1169:
1166:
1163:
1160:
1157:
1154:
1151:
1148:
1144:
1140:
1137:
1132:
1128:
1120:
1119:
1118:
1101:
1095:
1092:
1089:
1083:
1078:
1074:
1066:
1065:
1064:
1062:
1046:
1022:
1019:
1016:
1010:
1007:
1000:
999:
998:
994:
975:
972:
969:
966:
963:
960:
957:
954:
951:
947:
943:
940:
935:
932:
929:
926:
923:
920:
917:
914:
910:
906:
903:
900:
890:
889:
888:
885:
871:
846:
842:
838:
835:
812:
809:
806:
803:
800:
785:of the system
784:
768:
765:
762:
759:
756:
753:
733:
727:
722:
718:
709:
707:of the system
706:
690:
670:
650:
644:
639:
635:
626:
625:
624:
622:
611:
607:
605:
601:
597:
587:
585:
567:
564:
560:
551:
547:
543:
537:
533:
531:
527:
509:
505:
479:
474:
470:
454:
450:
444:
438:
435:
432:
429:
426:
423:
420:
417:
414:
411:
407:
403:
398:
393:
389:
373:
369:
363:
357:
354:
351:
348:
345:
342:
339:
336:
333:
329:
325:
320:
311:
300:
299:
298:
282:
278:
260:
242:
233:
206:
203:
200:
194:
177:
173:
156:
149:
146:
143:
137:
117:
113:
99:
91:
90:
89:
86:
84:
83:bond energies
80:
76:
72:
54:
45:
33:
19:
2815:
2806:
2797:
2791:
2782:
2763:
2757:
2738:
2732:
2720:
2713:Laidler K.J.
2708:
2689:
2661:
2629:
2623:
2604:
2598:
2580:
2572:
2533:and thereby
2490:Gibbs energy
2486:voltaic cell
2384:
2379:
2366:and water (H
2345:
2342:
2204:
2202:
2185:
2053:
2048:
1962:
1924:
1674:
1520:
1116:
1038:
995:
992:
886:
788:
617:
608:
593:
590:Introduction
584:biochemistry
538:
534:
496:
221:
87:
31:
29:
2348:calorimeter
2278:unsaturated
2830:Categories
2590:References
2576:Hess's law
2362:) to form
2352:combustion
2326:→ 1/2 MgCl
2242:(g) → 2 CO
1556:, we have
75:enthalpies
2725:Atkins P.
2556:⊖
2542:Δ
2457:
2416:⊖
2402:Δ
2292:(g) + 2 H
2282:acetylene
2246:(g) + 3 H
2159:∘
2146:Δ
2134:∘
2125:∫
2112:∘
2097:∘
2089:Δ
2069:∘
2061:Δ
2023:Δ
2001:∂
1993:Δ
1990:∂
1934:Δ
1908:⊖
1889:Δ
1879:ν
1836:∑
1832:−
1827:⊖
1808:Δ
1798:ν
1758:∑
1749:⊖
1735:Δ
1724:⊖
1689:⊖
1657:Δ
1617:∑
1614:−
1580:∑
1422:∑
1419:−
1338:∑
1263:∑
1260:−
1226:∑
1178:∑
1175:−
1141:∑
1099:Δ
1087:Δ
1014:Δ
944:∑
941:−
907:∑
898:Δ
869:Δ
833:Δ
810:−
798:Δ
731:Δ
703:) is the
648:Δ
565:−
506:ν
480:⊖
461:Δ
451:ν
408:∑
404:−
399:⊖
380:Δ
370:ν
330:∑
321:⊖
308:Δ
283:⊖
269:Δ
243:⊖
230:Δ
178:ν
157:ν
153:→
118:ν
100:ν
55:⊖
42:Δ
34:(denoted
2836:Enthalpy
2330:(aq) + H
2205:standard
1059:is only
783:enthalpy
746:, where
663:, where
524:are the
316:reaction
238:reaction
69:) for a
50:reaction
2296:(g) → C
2261:(g) → C
781:is the
2770:
2745:
2696:
2668:
2636:
2611:
2250:O (l).
2228:ethane
2220:oxygen
1870:
1789:
1035:(work)
552:) and
442:
361:
198:
192:
141:
135:
2334:O(l).
602:into
2768:ISBN
2743:ISBN
2694:ISBN
2666:ISBN
2634:ISBN
2609:ISBN
2304:(g).
2269:(g).
30:The
2546:rxn
2406:rxn
2393:as
2354:of
2257:3 H
1938:rxn
1739:rxn
1039:If
2832::
2680:^
2648:^
2570:.
2454:ln
2222:(O
2211:.
561:10
2776:.
2751:.
2702:.
2674:.
2642:.
2617:.
2552:H
2521:)
2518:T
2515:(
2509:q
2506:e
2501:K
2469:q
2466:e
2461:K
2448:T
2445:d
2441:d
2433:2
2429:T
2425:R
2421:=
2412:H
2380:H
2368:2
2360:2
2332:2
2328:2
2324:2
2302:6
2300:H
2298:2
2294:2
2290:2
2288:H
2286:2
2267:6
2265:H
2263:2
2259:2
2248:2
2244:2
2240:2
2236:6
2234:H
2232:2
2224:2
2170:T
2166:d
2154:P
2150:C
2141:T
2130:T
2121:+
2117:)
2108:T
2104:(
2093:H
2086:=
2082:)
2079:T
2076:(
2065:H
2045:.
2031:p
2027:C
2020:=
2015:p
2010:)
2004:T
1996:H
1984:(
1943:H
1903:r
1899:H
1893:f
1883:r
1873:r
1867:,
1864:s
1861:t
1858:n
1855:a
1852:t
1849:c
1846:a
1843:e
1840:r
1822:p
1818:H
1812:f
1802:p
1792:p
1786:,
1783:s
1780:t
1777:c
1774:u
1771:d
1768:o
1765:r
1762:p
1754:=
1745:H
1731:=
1720:P
1715:Q
1685:P
1660:H
1654:=
1649:s
1646:t
1643:n
1640:a
1637:t
1634:c
1631:a
1628:e
1625:r
1621:H
1609:s
1606:t
1603:c
1600:u
1597:d
1594:o
1591:r
1588:p
1584:H
1577:=
1572:P
1568:Q
1544:V
1541:P
1538:+
1535:U
1532:=
1529:H
1505:)
1499:s
1496:t
1493:n
1490:a
1487:t
1484:c
1481:a
1478:e
1475:r
1471:V
1467:P
1464:+
1459:s
1456:t
1453:n
1450:a
1447:t
1444:c
1441:a
1438:e
1435:r
1431:U
1426:(
1415:)
1409:s
1406:t
1403:c
1400:u
1397:d
1394:o
1391:r
1388:p
1384:V
1380:P
1377:+
1372:s
1369:t
1366:c
1363:u
1360:d
1357:o
1354:r
1351:p
1347:U
1342:(
1335:=
1330:P
1326:Q
1301:)
1295:s
1292:t
1289:n
1286:a
1283:t
1280:c
1277:a
1274:e
1271:r
1267:V
1255:s
1252:t
1249:c
1246:u
1243:d
1240:o
1237:r
1234:p
1230:V
1222:(
1218:P
1215:+
1210:s
1207:t
1204:n
1201:a
1198:t
1195:c
1192:a
1189:e
1186:r
1182:U
1170:s
1167:t
1164:c
1161:u
1158:d
1155:o
1152:r
1149:p
1145:U
1138:=
1133:P
1129:Q
1102:V
1096:P
1093:+
1090:U
1084:=
1079:P
1075:Q
1047:W
1023:W
1020:+
1017:U
1011:=
1008:Q
976:s
973:t
970:n
967:a
964:t
961:c
958:a
955:e
952:r
948:U
936:s
933:t
930:c
927:u
924:d
921:o
918:r
915:p
911:U
904:=
901:U
872:U
847:V
843:Q
839:=
836:U
813:W
807:Q
804:=
801:U
769:V
766:P
763:+
760:U
757:=
754:H
734:H
728:=
723:P
719:Q
691:E
671:U
651:U
645:=
640:V
636:Q
568:7
510:i
475:r
471:H
465:f
455:r
445:r
439:,
436:s
433:t
430:n
427:a
424:t
421:c
418:a
415:e
412:r
394:p
390:H
384:f
374:p
364:p
358:,
355:s
352:t
349:c
346:u
343:d
340:o
337:r
334:p
326:=
312:H
279:H
273:f
234:H
207:.
204:.
201:.
195:+
188:Y
182:Y
174:+
170:X
163:X
150:.
147:.
144:.
138:+
131:B
124:B
114:+
110:A
104:A
46:H
20:)
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