精英家教网 > 高中地理 > 题目详情

【题目】根据你的生活经验和下表所提供的信息,分析并回答下列问题。

物理性质

物质性质比较

导电性(以银的导电性为100作标准)

100

99

74

61

27

17

7.9

密度/(g·cm3)

19.3

11.3

10.5

8.92

7.86

7.14

2.70

熔点/

3410

1535

1083

1064

962

660

232

硬度(以金刚石的硬度为10作标准)

9

4~5

2.5~4

2.5~3

2.5~3

2~2.9

1.5

(1)为什么菜刀、锤子等通常用铁制而不能用铅制?___________________。

(2)银的导电性比铜好,为什么导线一般用铜制而不用银制?_____________。

(3)为什么灯泡里的灯丝用钨制而不用锡制?_________________。

【答案】(1)因为铁的硬度比铅大,且铅有毒,故常用铁而不用铅制菜刀、锤子(2分)

(2)银和铜的导电性相近,但银比铜的价格贵得多,且电线用量大,所以用铜不用银(2分)

(3)因为钨的熔点(3 410 )高,而锡的熔点(232 )太低,通电时锡很快就熔化了,所以用钨丝而不用锡丝作灯泡的灯丝(2分)

【解析】在确定金属的用途时,要考虑其硬度、熔点、导电性等多种性质;有时还要考虑价格、资源、是否便利、是否有毒、是否利于回收等因素。正确解答本题还要会读题,要充分利用题中所给信息。

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