搜题请搜索小程序“爱下问搜题”
问题 选择题

铁锈的主要成分是Fe2O3，除锈的原理是：Fe2O3 + 3H2SO4 = Fe2(SO4)3 + 3H2O。该原理利用的硫酸性质是

A.氧化性           B.还原性             C吸水性          D.酸性

答案

答案：D

铁锈是碱性氧化物,所以可以与酸反应,所以该原理利用的硫酸性质是酸性

故选D

听力题

第一节单词拼写(10小题；每小题1分,满分10分)

小题1:He was suspected of p_________________(毒害his wife.

小题2:No one can p_________________（预测）what will happen one day.

小题3:Teachers shouldn’t show p_______________(偏爱) to any student.

小题4:The picture by Picasso a_______________(吸引) to all the students here.

小题5:It was t_______________(典型的) of her to help others when they are in trouble.

小题6:He has lost f_______________(信任)in me

小题7:I found it hard to c______________(表达) my feeling in words.

小题8:May I e_______________(交换) seats with you?

小题9:He is gifted and good at writing p______________(诗歌).

小题10:He a_____________ (申请) for the job.

查看答案
单项选择题

分电器触点氧化、烧蚀的主要原因是（）

A.触点间隙过小或分离不彻底

B.电容器失效或电容量太小

C.断电器弹簧力不足
查看答案