Dab tsi yog qhov kub ntawm kev tsim ntawm ib lub caij?
Dab tsi yog qhov kub ntawm kev tsim ntawm ib lub caij?

Video: Dab tsi yog qhov kub ntawm kev tsim ntawm ib lub caij?

Video: Dab tsi yog qhov kub ntawm kev tsim ntawm ib lub caij?
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Kub ntawm kev tsim . Kub ntawm kev tsim , kuj hu ua standard kub ntawm kev tsim , enthalpy offormation , los yog standard enthalpy ntawm kev tsim , tus nqi kub absorbed los yog evolved thaum ib tug mole ntawm ib tug compound yog tsim los ntawm nws cov ntsiab lus, txhua yam khoom nyob rau hauv nws lub cev lub cev (gas, kua, los yog khoom).

Tsis tas li ntawd, qhov kub ntawm kev tsim txhais li cas?

Hauv chemistry, kub ntawm kev tsim yog cov kub tso tawm los yog nqus tau ( enthalpy hloov) thaum lub sijhawm tsim ntawm cov khoom ntshiab los ntawm nws cov ntsiab lus ntawm qhov siab tsis tu ncua (hauv lawv cov qauv txheem). Kub offormation feem ntau yog denoted los ntawm ΔHf. Nws yog feem ntau qhia nyob rau hauv units ntawm kilojoules ib mole (kJ / mol).

Tsis tas li ntawd, dab tsi yog qhov kub ntawm kev tsim cov dej? Hydrogen thiab oxygen sib xyaw ua ke dej . Ib yam li lwm cov tshuaj tiv thaiv, cov no yog nrog los ntawm kev nqus los yog tso tawm ntawm kub . Tus qauv kub ntawm kev tsim yog enthalpy kev hloov pauv cuam tshuam nrog tsim ntawm ib tug mole ntawm ib tug compound los ntawm nws cov ntsiab lus nyob rau hauv lawv standardstats.

Ib tug kuj yuav nug, dab tsi yog qhov kub ntawm kev tsim rau ib lub caij nyob rau hauv nws tus qauv lub xeev?

Cov tus qauv enthalpy ntawm kev tsim rau ib lub caij hauv nws lub xeev tus qauv yog ZERO!!!! Cov ntsiab lus hauv lawv txheem xeev tsis tsim, lawv tsuas yog. Yog li, ΔH°f rau C (s, graphite) yog xoom, tab sis ΔH°f rau C (s, pob zeb diamond) yog 2 kJ / mol. Qhov ntawd yog vim graphite yog qhov txheem xeev rau carbon, notdiamond.

Dab tsi yog lub ntsiab lus ntawm qhov kub ntawm cov tshuaj tiv thaiv?

Txhais ntawm tshav kub ntawm cov tshuaj tiv thaiv .: cov kub evolved los yog absorbed thaum lub sij hawm tshuaj tshuaj tiv thaiv noj placeunder tej yam kev mob ntawm qhov kub thiab txias ntawm ob qho tib si constantvolume los yog ntau zaus tas li siab tshwj xeeb tshaj yog: qhov quantityinvolved thaum gram sib npaug ntawm cov tshuaj nkag mus rau hauv lub tshuaj tiv thaiv.

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