Cov tshuaj tiv thaiv tshuaj yog hais txog cov txheej txheem uas cov molecules tawg rau hauv atoms thiab cov atoms rov kho dua thiab ua ke los tsim cov molecules tshiab. Cov tshuaj tiv thaiv yog feem ntau nrog luminescence, tshav kub tiam, discoloration, tsim precipitates, thiab lwm yam. Lub hauv paus rau kev txiav txim seb ib tug tshuaj tiv thaiv yog ib tug tshuaj tiv thaiv yog seb cov tshuaj tiv thaiv generates tshiab molecules.
