0.0542mol x(NaCl ) =0.10 0.0542mol+0.491mol 0.491mol x(H,O)= =0.90 或 0.0542mol+0.491mol x(H,0)=1-0.10=0.90 注意：解题的步骤要书写清楚；数学运算要准确 19 止页下页 节首节尾19 0 10 0 0542 0 491 0 0542 . . . . ( ) =  = mol mol mol x NaCl 注意:解题的步骤要书写清楚;数学运算要准确. 1 0 10 0 90 0 90 0 0542 0 491 0 491 2 2 ( ) . . . . . . ( ) = - = =  = x H O mol mol mol x H O 或