塔里木盆地的年降水量在
A:800毫米以上
B:400毫米至800毫米
C:50毫米以下
D:200毫米以下
— I haven't heard ______ Peter yet.
— Don't worry. No news is good news. His letter will arrive soon.
He won the match because he took the advantage of his height.
下列各组微粒能大量共存,当加入相应试剂后会发生化学变化,且发生反应的离子方程式书写正确的是( )
选项
微粒组
所加试剂
离子方程式
A
NH4+、Mg2+、SO42﹣
少量Ba(OH)2溶液
NH4++SO42﹣+Ba2++OH﹣=BaSO4↓+NH3•H2O
B
Mg2+、HCO3﹣、Cl﹣
过量NaOH溶液
Mg2++2HCO3﹣+2OH﹣=MgCO3﹣↓+CO32﹣+2H2O
C
H+、Na+、NO3﹣
Fe粉
Fe+2H+=Fe2++H2↑
D
Ca2+、NH3•H2O、Cl﹣
通入过量CO2
NH3•H2O+CO2=NH4++HCO3﹣
用实验证明Mg、Fe、Cu三种金属的活动性顺序,可选择