Cov kuab tshuaj yog cov kua (gas lossis khoom) uas tuaj yeem yaj cov khoom, kua, lossis cov kua roj gaseous, yog li tsim cov tshuaj. Dej yog qhov hnyav tshaj plaws hauv lub neej txhua hnub. Organic kuab tshuaj yog cov organic compounds uas muaj carbon atoms. Cov kuab tshuaj feem ntau muaj cov ntsiab lus boiling tsawg thiab yooj yim volatile. Lawv tuaj yeem raug tshem tawm los ntawm distillation, tawm hauv cov khoom yaj. Yog li ntawd, cov kuab tshuaj tsis tuaj yeem ua rau tshuaj lom nrog cov kuab tshuaj; lawv yuav tsum yog inert. Cov kuab tshuaj tuaj yeem tshem tawm cov sib xyaw ua ke ntawm cov khoom sib tov; piv txwv tshaj yog brewing kas fes los yog tshuaj yej nrog dej kub. Cov kuab tshuaj feem ntau yog pob tshab, tsis muaj xim, thiab feem ntau muaj cov ntxhiab tsw txawv.
Qhov concentration ntawm cov tshuaj yog nyob ntawm tus nqi ntawm cov tshuaj yaj nyob rau hauv cov kuab tshuaj. Solubility yog qhov siab tshaj plaws ntawm cov khoom uas ib qho hnyav tuaj yeem yaj ntawm qhov kub thiab txias. Organic kuab tshuaj yog siv nyob rau hauv qhuav tu (xws li, tetrachloroethylene), raws li cov xim thinners (xws li, toluene, turpentine), raws li ntsia thawv polish remover los yog kua nplaum remover (xws li, acetone, methyl acetate, ethyl acetate), raws li xeb Remover (xws li, hexane), raws li ib tug detergent (thesis perfumes) nyob rau hauv cov tshuaj chemical.
