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Date: 12-7-2018
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Date: 23-8-2019
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Date: 23-8-2019
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Some common aromatic hydrocarbons consist of fused benzene rings—rings that share a common side. These compounds are called polycyclic aromatic hydrocarbons (PAHs).
The three examples shown here are colorless, crystalline solids generally obtained from coal tar. Naphthalene has a pungent odor and is used in mothballs. Anthracene is used in the manufacture of certain dyes. Steroids, a large group of naturally occurring substances, contain the phenanthrene structure.
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15 نوعا من الأطعمة تساعدك على ترطيب جسمك خلال موجة الحر
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دول عربية تقرر قطع الكهرباء لساعات محددة يوميا بسبب الحرارة
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بالصور: بمناسبة عيد الغدير الاغر.. قراءة خطبة النبي الأكرم (ص وآله) بالمسلمين في يوم (غدير خم)
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