题目

America is a mobile society. Friendships between Americans can be close and real, yet disappear soon. They don ’t feel hurt. If the same two people meet again, even years later, they pick up the friendship .This can be quite difficult for us Chinese to understand .Friendships between us develop more slowly but may become lifelong feelings, extending（延伸）deeply into both families. There is another difficult point for us to understand . Although Americans treat friends warmly in their personal everyday lives, they don’t show their politeness to them if it requires a great deal of ti18．如图是初中化学常见物质之间的转化关系，他们各代表不同的物质（“-”表示相邻的与两种物质可以发生反应，“→”表示箭头的物质可转化为箭头后的物质；部分反应的反应物、生成物和反应条件未标出）．其中A、H是金属氧化物，且H是红色固体粉末，F是由两种元素组成的化合物．请回答下列问题：（1）C的化学式是CO2．（2）写出物质E的一种用途改良酸性土壤．（3）图中有几种物质都能与F发生反应，请你写出其中一种物质与F发生复分解反应的化学方程式：2HCl+Ca（OH）2=CaCl2+2H2O．（4）写出下列反应的化学方程式D与H：3CO+Fe2O3$\frac{\underline{\;高温\;}}{\;}$2Fe+3CO2．E→B：Ca（OH）2+CO2═CaCO3↓+H2O．