الاختبارات المعملية لخصائص الذهب والفضة: دليل مرئي

Let's examine the visual and physical properties of gold and silver.Gold has a distinctive yellow luster, while silver has a bright silvery shine.To measure density, we use a sensitive balance and distilled water.Pure gold has a density of 19.3 grams per cubic centimeter, while silver's density is 10.5 grams per cubic centimeter.Both metals are highly malleable and ductile, meaning they can be easily shaped without breaking.For the nitric acid test, we observe how pure gold and silver react differently.Pure gold remains unchanged in nitric acid, while silver dissolves completely.Next, we use sodium chloride to test for silver ions, which form a white silver chloride precipitate.Finally, we use aqua regia, a mixture of nitric and hydrochloric acids, which can dissolve gold.The aqua regia solution turns yellow-orange as it dissolves the gold, forming gold chloride complexes.The XRF spectral analyzer precisely determines the composition of metal alloys.When the X-ray beam hits the sample, it reveals the exact percentages of each element present.Silver has the highest electrical conductivity of all metals, followed by copper and gold.The melting points of these precious metals are also distinctive. Gold melts at 1064 degrees Celsius, while silver melts at 962 degrees.