下列解释实验现象的反应方程式正确的是( )
A:在CH3COONa溶液中,滴加酚酞变红:CH3COO﹣+H2O═CH3COOH+OH﹣
B:在H2O2溶液中,滴加FeCl3溶液产生气泡:2H2O2+2Cl﹣═2H2O+O2↑+Cl2↑
C:将相互接触的铜片和锌片置于稀硫酸中,铜片表面有气泡产生:Cu+2H+═Cu2++H2↑
D:向Cu(OH)2悬浊液中滴加Na2S溶液,蓝色沉淀变黑色:Cu(OH)2(s)+S2﹣ (aq)⇌CuS(s)+2OH﹣ (aq)
下列方程是一元一次方程的是( ).
读植物嫁接的过程示意图,回答下列问题
根据句子意思或音标写出单词的适当形式。My cousin Jack is in Class 2, G____ 7 in our school.The family like eating in the r____ instead of (代替) at home on Sunday.T____ is the fifth day of a week.We do morning e____ every day.There are 6 h____ students in my school.
The sports shoes are those____ (child).Daniel ,____ (not talk) in class.This pair of blue jeans ____ (be) beautiful.Millie gets a lot of ____ 'preznts at Christmas.Where are my ____ 'trauz?z ?
我国去南极进行科学考察的最佳时间是每年的( )
在含有FeSO4的溶液中投入一小块金属钠,反应完全后,滤出沉淀并洗涤之,然后在空气中灼烧沉淀得到的固体物质是( )