Why chromium resists the effect of atmosphere
Chromium is chemically active, yet resists air: the oxide that forms on its surface has a larger volume than the metal atoms it came from, so it forms a continuous non-porous layer that blocks further reaction with oxygen.
The idea, in English
Chromium is chemically active, yet resists air: the oxide that forms on its surface has a larger volume than the metal atoms it came from, so it forms a continuous non-porous layer that blocks further reaction with oxygen.
Explain in Egyptian Arabic
الـ chromium عنصر نشيط كيميائيًا، ومع ذلك بيقاوم الهوا: الـ oxide اللي بيتكوّن على سطحه حجمه أكبر من حجم ذرات الـ metal اللي اتكوّن منها، فبيعمل طبقة متصلة non-porous بتمنع إن الـ oxygen يكمّل تفاعل معاه.
المطلوب
إنك تقدر تدّي السبب ده (give reasons)، وتقارنه بطبقة porous (زي الـ rust) بتسيب الـ corrosion يكمّل.
Common misconceptions
- Chromium resists air because it is an unreactive metal.
No. Chromium is a chemically active metal. It resists the air because the oxide formed on its surface has a larger volume than the metal atoms, making a non-porous layer that stops further reaction with oxygen.
Explain in Egyptian Arabic
لأ، الـ chromium metal نشيط فعلًا؛ اللي بيحميه هو طبقة الـ oxide اللي على سطحه.
- Any oxide layer protects a metal.
Not any layer. Chromium's oxide has a larger volume than the metal atoms it came from, so it forms a continuous non-porous layer that stops oxygen from reaching the metal. A porous layer, like rust, lets the reaction continue underneath.
Explain in Egyptian Arabic
مش أي طبقة؛ الطبقة الـ non-porous تحديدًا هي اللي بتحمي.