铜与硝酸银置换反应的条件及机理探究

Study on Conditions and Mechanism of Copper-Silver Nitrate Displacement Reaction

在铜与硝酸银溶液反应中通常观察到铜表面析出光亮的银，较难观察到银晶体的形状。为了更清晰地观察银晶体析出的形态，采用实验探究法，以琼脂和水为介质，探究不同介质、温度、浓度下银析出的形态及其机理。结果显示，在琼脂中银为树枝状，溶液中为团簇状，并且在溶液中随着温度升高或浓度降低，银单质分枝变多、变细长。结果可以用琼脂的三维网状结构和晶体的位错生长机理来解释。

In copper-silver nitrate replacement reaction,it was usually observed that bright silver separated out on the surface of copper in water medium,but it was difficult to observe the shape of silver crystals.In order to see the morphology of silver crystals more clearly,this paper inquired the morphology and mechanism of silver precipitation under different media,temperature and concentration with agar and water as medium.The results showed that the silver was dendritic in agar and was flaky in solution,and the silver branch became variable and slender with the increase of temperature or the decrease of concentration in solution.The results could be explained by the three-dimensional network structure of agar and the screw dislocation growth mechanism of crystals.