實(shí)驗(yàn)室欲配制50g5%的食鹽溶液,實(shí)驗(yàn)步驟如下.
(1)計(jì)算：需要食鹽質(zhì)量為____g,水的質(zhì)量為____g,約____mL.
(2)稱量：托盤天平只能對(duì)準(zhǔn)稱量到____g,檢查時(shí).若發(fā)現(xiàn)指針偏右,應(yīng)將平衡螺母向____調(diào)節(jié)至平衡.稱量時(shí)若把砝碼放在左盤（1g一下用游碼）,則稱得食鹽的實(shí)際質(zhì)量為____g；若量取水的操作正確,所配溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)實(shí)際為____.要把該溶液變成5%的溶液,需再加食鹽____g.
（3）溶解：應(yīng)選擇的量筒規(guī)格是____（填“50mL”或“100mL”）,量取時(shí),若仰視刻度線,則量筒的讀數(shù)偏____,實(shí)際水的體積偏____,所配制溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)偏____.