试题与答案

这学期,小亮和班级的两名同学主动承担了维护班级花坛的工作。前不久,他们发现有部分

题型:实验题

题目:

这学期,小亮和班级的两名同学主动承担了维护班级花坛的工作。前不久,他们发现有部分花的叶面出现了枯黄的现象,便及时向花坛里施用了足量的化肥,但效果并不明显。他们决定用所学的化学知识来解决这一问题。

(收集资料)

(1)花的叶色枯黄,他们选择施用_____________(填写“氮”、“磷”或“钾”)肥是正确的。

(2)前一段时间他们曾用熟石灰(化学式为_______________)对花坛中的___________性土壤进行过改良。

(3)近一个星期一直无雨,气温较高。

(4)通过查阅资料,小亮和同学们知道:含NH4+的盐受热或与碱混合会放出有刺激性气味的氨气,氨气的水溶液呈碱性。

(提出假设)

(1)太阳的曝晒和气温升高都可使肥效流失。

(2)熟石灰与化肥反应也可使肥效流失。

(设计并进行实验)

(1)小亮取少量这种化肥于试管中加热,并在试管口放一条干燥的pH试纸,pH试纸无变化。

(2)另取少量这种化肥与熟石灰混合,闻到____________气味。

[他的结论)由以上第二个实验中的现象他能得出肥效流失与_____________有关。

(反思与应用)

(1)小亮进行的第一个实验中,pH试纸无变化,这与查阅资料给出的信息不符,其原因是

(2)参与了小亮和同学们的探究活动,想必你也一定受到了启发,你能对小亮保存剩余化肥提出一条合理化建议吗?

答案:

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