皮皮学，免费搜题
登录
搜题
【简答题】
实验室用粗锌与稀硫酸反应制取氢气，利用氢气还原氧化铜来测定铜的相对原子质量。实验装置如下： （1）在发生器中纯锌与稀硫酸反应过于缓慢，可采取的加快速率的措施是①适当增大硫酸的浓度，②_______________________。 （2）用纯度不高的锌(粗锌)制取氢气，反应速率快，但制得的氢气因含H 2 S等还原性杂质而有难闻的气味，CuSO 4 洗气瓶中观察到的现象是_______________，是否可以将CuSO 4 溶液换成浓硫酸_________(答“是”或“否”) ；理由是__________________________。 （3）有同学发现粗锌与稀硫酸反应一段时间后，锌粒表面变黑，于是收集了少量该黑色固体，验证黑色固体含铁元素的简单化学方法_________________________________________。 （4）实验中得到的数据有：皿的质量m g，皿加样品的质量n g，反应后皿加固体的质量w g，已知氧的相对原子质量为16，则铜的相对原子质量是____________(用含m、n、w的代数式表示)。 （5）某次实验中测定结果明显偏大，可能的原因是________(选填编号)。 a．未充分冷却即停止通氢气 b．氧化铜样品中含有氯化铵杂质 c．反应后固体中有少量Cu 2 O d．氢气不干燥有少量水分 （6）由于发生器药品用量较多，利用下列仪器装配一套有发生器功能的简易装置，你选择____________(选填编号) (支撑仪器、橡皮塞、导气管略)。 (a) (b) (c) (d) (e) (f)
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【多选题】In which situations, we can use "be going to" in the sentence?
A.
we intend to do something in the future.
B.
we have already decided to do something.
C.
when know that something will happen because of the situation now.
D.
when we think will happen in the future.
【单选题】I propose that she _______ (praise)
A.
parise
B.
will be praise
C.
(should) be praised
【简答题】Dear Aunty, I work at a supermarket, and another girl and I share tasks we must finish before leaving. But she takes half an hour to do something I can do in ten minutes. She always has a story to tel...
【单选题】In which situations should we use citation?
A.
Summarizing, Paraphrasing, Quoting
B.
Quoting, Summarizing, Proverbs
C.
Paraphrasing, Quoting, Common Knowledge
D.
Common Knowledge, Quoting, Better safe thansorry
【简答题】I propose that she _______ (praise)
【单选题】In which situations should we use citation?
A.
Quoting, Summarizing, Proverbs
B.
Paraphrasing, Quoting, Common Knowledge
C.
Summarizing, Paraphrasing, Quoting
D.
Common Knowledge, Quoting, Better safe than sorry
【多选题】In which situations, we can use "will" in the sentences?
A.
To describe a continuing action that started in the past.
B.
when we decide to do something at the moment of speaking.(The speaker has not decided before)
C.
when we think will happen in the future.
D.
to describe an experience.
【多选题】In which situations computers do not perform. better than the human mind?
A.
performing an operation
B.
docking a big ship
C.
playing backgammon
D.
doing the work of a postal clerk
【简答题】In which situations a jump is considered as a failure?
【单选题】In which situations should we use citation?
A.
Quoting, Summarizing, Proverbs
B.
Paraphrasing, Quoting, Common Knowledge
C.
Common Knowledge, Quoting, Better safe than sorry
D.
Summarizing, Paraphrasing, Quoting
相关题目：