【单选题】将0.2mol/L的醋酸(Ka=1.8×10-5)与O.2mol/L醋酸钠溶液混合,为使溶液的pH值维持在4.05,则酸和盐的比例应为( )。
【单选题】For Melissa, what is the best part of her job?
B.
There a lot of free time.
C.
The job is exhausting.
D.
The job is fun and people are surprised.
【简答题】”补天“的典故是指_______________________________________________________________________________________________________________________________________________________________________________________________...
【单选题】下列事实能说明醋酸是弱酸的是 ①下当温度低于16.6℃时醋酸可凝结成冰一样晶体 ②0.1 mol/L的醋酸钠溶液的pH约为9 ③等体积等物质的量浓度的硫酸比醋酸消耗氢氧化钠多 ④0.1mol/L的醋酸的pH值约为4.8 ⑤pH等于4且等体积的醋酸和盐酸,与等浓度NaOH溶液充分反应时,醋酸液消耗碱液多
【简答题】下面的文字优美深刻,富含哲理,读一读,完成 3 ~ 5 题。 珍惜阅读,便是珍惜历史,珍惜至今残留的石鼓文陶埙 (x ū n ,古代吹奏乐器 ) 石罄 发出的音响以及青铜瓦当上的装饰画。 珍惜阅读,便是珍惜传统,珍惜乐山大佛永乐大钟以及太极八卦少当飒飒英姿 猎猎雄风。 珍惜阅读,便是珍惜文学,珍惜楚韵唐诗宋词,乃至 ① 的西游 , ② 的三国 , ③ 的红楼。 珍惜阅读,便是 3 、将下列...
【单选题】能说明醋酸是弱酸的是:
B.
1 m o 1/L的醋酸钠溶液的PH值约为9
D.
1 m o 1/L的醋酸水溶液能使紫色石蕊试液变红
【简答题】A.She has a part-time job. B.She received a scholarship. C.Her parents pay for it. D.She is working as a tourist guide.
【简答题】A.The woman is likely to do a part-time job to get some money. B.The man is going to offer some money to the woman. C.The woman has no choice but to ask for money from her parents. D.The man will find...