現(xiàn)有t1℃時(shí)某溶液l00g,溶質(zhì)質(zhì)量分?jǐn)?shù)為20%,溶液密度為1.5g/mL,降溫至t2℃時(shí)有5g晶體(不含結(jié)晶水)析出,則t2℃時(shí)溶液的溶質(zhì)質(zhì)量分?jǐn)?shù)為( )
A. 25.4%
B. 20.3%
C. 15.8%
D. 5.9%
由t1℃時(shí)某溶液l00g,溶質(zhì)質(zhì)量分?jǐn)?shù)為20%,
則溶質(zhì)的質(zhì)量為100g×20%=20g,
溶劑的質(zhì)量為100g-20g=80g,
再由降溫至t2℃時(shí)有5g晶體析出,且晶體中不含結(jié)晶水,
則t2℃時(shí)溶液中的溶質(zhì)質(zhì)量為20g-5g=15g,
則t2℃時(shí)溶液的溶質(zhì)質(zhì)量分?jǐn)?shù)為
×100%=15.8%,
故選C.