1 method is to look at the hardness. The hardness of copper is higher than that of gold, while gold is softer, and teeth marks can be bitten with a gentle bite.

The second method is to observe the color. The color of gold is beautiful, while the color of copper is much darker, although it is all yellow metal.

The third method is to listen to the sound by tapping. Copper has sound and rhyme, gold has sound and no rhyme, no echo and no rhyme.

The fourth method is to look at the jumping ability. When gold or copper is thrown to the ground, copper will have jumping ability, while gold has no jumping ability.

The fifth method is to look at the degree of oxidation. Gold is a rare metal, which has a high degree of oxidation resistance and is not easy to corrode. Put some vinegar on copper and it will rust and turn green the next day.

brief introduction

The simple substance (free form) of gold, commonly known as gold, is a precious metal, which has been used as currency, preservation and jewelry for many centuries. In nature, gold exists in the form of simple substance in gold nuggets or rocks, underground veins and alluvium. Gold is also one of the currency metals. Gold is solid at room temperature, with high density, softness, brightness and corrosion resistance. It is the metal with the best ductility, second only to platinum.

Gold is a transition metal, which can form trivalent and monovalent positive ions after dissolution. Gold does not react chemically with most substances, but can be corroded by chlorine, fluorine, aqua regia and cyanide. Gold can be dissolved by mercury to form gold amalgam (this is not a chemical reaction); Nitric acid that can dissolve silver cannot dissolve gold. The above two properties become the basis of gold refining technology, which are called "separate casting" and "separate casting" respectively.