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Date: 26-12-2018
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Date: 30-3-2019
1262
Date: 4-12-2018
1085
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Aluminum ranks third on the list of the ten most abundant elements in the earth's crust, while its oxide is fourth among the ten most common compounds in the crust. It is the most abundant metal on the planet. Its name is taken from the Latin alumen for alum. Soft, lightweight and silvery, its existence was proposed by Lavoisier in 1787, it was named by Davy in 1807 and finally isolated by Ørsted in 1825. Before this, it was known for being part of alum, which is used as a mordant to help set dye on fabric. At this time it was known as a very expensive metal. In the late 1800s, two scientists, Charles Martin Hall and Paul L. T. Heroult, found that they could produce aluminum from aluminum oxide through electrolysis and a cryolite (molten mineral) solvent. This allowed the price to decrease and for aluminum to become available for commercial use.
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علامات بسيطة في جسدك قد تنذر بمرض "قاتل"
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أول صور ثلاثية الأبعاد للغدة الزعترية البشرية
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مكتبة أمّ البنين النسويّة تصدر العدد 212 من مجلّة رياض الزهراء (عليها السلام)
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