题干

某同学对生铁的组成进行研究.称取生铁样品40g,把500g稀硫酸分5次加入样品中,测得实验数据见下表:(生铁中的杂质不溶于水,也不和稀硫酸反应)

(1)第4次剩余固体的质量m=____ g
(2) 该生铁样品中铁的质量分数为____ ;
(3) 计算所用稀硫酸的溶质质量分数____ 。

上一题 下一题 0.0难度 选择题 更新时间:2017-06-16 05:19:52

答案(点此获取答案解析)

1.2g,97%,19.6%

同类题2

阅读理解

    The 2016 Rio Olympic Games have come to an end. Without doubt, many Chinese sports fans sat in front of the TV and cheered our athletes on, hoping that they would get as many gold medals as possible.

    But sometimes our desire for gold medals can result in the sadness of failure. When Liu Xiang, China's track hero, pulled out of the Beijing Olympics due to injury, he greatly disappointed many Chinese sports fans.

    But things are different now. In the 2016 Rio Olympic Games, we saw a healthier and more lenient Chinese attitude toward the sports people, fully in line with the Olympic spirit.

    China didn't win any gold medals on the first day. But, instead of criticizing the athletes who failed to finish on top of the podium(领奖台), the majority of fans were happy with their efforts. “Reacting in the right way when an athlete misses out on gold shows the maturity of a person, and is also a challenge for a country to face up to in the process of development,” commented CRI.

    Swimmer Fu Yuanhui won fans' hearts, even if she only won a bronze medal in the 100m backstroke final. Her fans on her Sina Weibo micro blog have increased 100,000 to over 6 million. Many sports fans appreciated her straightforward character and attitude toward competition.

    “The warm support from Internet users shows that public attitude toward competitive sport and the Olympics have gotten to a higher level,” said an article in the People's Daily.

同类题3

阅读梁启超先生的《敬业与乐业》选段,完成下列各题。
                                                                                                      敬业与乐业(节选)
       ①我这题目,是把《礼记》里头“敬业乐群”和《老子》里头“安其居,乐其业”那两句话,断章取义造出来的。我所说的是否与《礼记》《老子》原意相合,不必深求;但我确信“敬业乐业”四个字,是人类生活的不二法门。
   ②本题主眼,自然是在“敬”字、“乐”字。但必先有业,才有可敬、可乐的主体,理至易明。所以在讲演正文以前,先要说说有业之必要。
   ③孔子说:“饱食终日,无所用心,难矣哉!”又说:“群居终日,言不及义,好行小慧,难矣哉!”孔子是一位教育大家,他心目中没有什么人不可教诲,独独对于这两种人便摇头叹气说道:“难!难!”可见人生一切毛病都有药可医,惟有无业游民,虽大圣人碰着他,也没有办法。
   ④唐朝有一位名僧百丈禅师,他常常用两句格言教训弟子,说道:“一日不做事,一日不吃饭。”他每日除上堂说法之外,还要自己扫地、擦桌子、洗衣服,直到八十岁,日日如此。有一回,他的门生想替他服务,把他本日应做的工悄悄地都做了,这位言行相顾的老禅师,老实不客气,那一天便绝对地不肯吃饭。
   ⑤我征引儒门、佛门这两段话,不外证明人人都要有正当职业,人人都要不断地劳作。倘若有人问我:“百行什么为先?万恶什么为首?”我便一点不迟疑答道:“百行业为先,万恶懒为首。”没有职业的懒人,简直是社会上的蛀米虫,简直是“掠夺别人勤劳结果”的盗贼。我们对于这种人,是要彻底讨伐,万不能容赦的。今日所讲,专为现在有职业及现在正做职业上预备的人——学生——说法,告诉他们对于自己现有的职业应采何种态度。