Catalytic activity of transition elements
Transition metals and their compounds are ideal catalysts because their 4s and 3d electrons form bonds between surface atoms and reacting molecules; this raises the reactants' concentration on the surface and weakens their bonds, lowering activation energy and speeding the reaction.
The idea, in English
Transition metals and their compounds are ideal catalysts because their 4s and 3d electrons form bonds between surface atoms and reacting molecules; this raises the reactants' concentration on the surface and weakens their bonds, lowering activation energy and speeding the reaction.
Explain in Egyptian Arabic
الـ transition metals والـ compounds بتاعتها catalysts مثالية، عشان الـ 4s والـ 3d electrons بتاعتها بتكوّن bonds بين ذرات السطح والـ reacting molecules. ده بيزوّد الـ concentration بتاع الـ reactants على السطح وبيضعّف الـ bonds اللي فيهم، فالـ activation energy بتقل والـ reaction بيسرع.
المطلوب
تقول السبب ده وتقرا الـ energy profile (شكل 1-3: الحدبة أوطى مع الـ catalyst، ونفس الـ net energy released).
Common misconceptions
- A catalyst is used up in the reaction.
No. A catalyst is not used up: its mass is the same at the end of the reaction. That is why it is written over the arrow, not among the reactants (like Fe in the Haber-Bosch method).
Explain in Egyptian Arabic
لأ، الـ catalyst مش بيتستهلك في الـ reaction: كتلته في الآخر زي ما هي، وعشان كده بيتكتب فوق السهم مش قبله (زي الـ Fe في طريقة الـ Haber-Bosch).
- A catalyst increases the amount of product or the energy released.
No. A catalyst lowers the activation energy, so the same reaction goes faster. The energy levels of the reactants and the products do not move, so the net energy released stays the same (fig 1-3).
Explain in Egyptian Arabic
لأ، الـ catalyst بيقلل الـ activation energy لوحدها. مستوى الـ reactants والـ products مابيتحركش، فالـ net energy released بتفضل زي ما هي.
- Activation energy is the energy given out by the reaction.
No. Activation energy is the climb from the reactants' level to the top of the hump. The energy the reaction gives out is the net energy released: the drop from the reactants' level to the products' level.
Explain in Egyptian Arabic
لأ، الـ activation energy هي الطلعة من مستوى الـ reactants لحد قمة الحدبة. إنما الـ energy اللي الـ reaction بيطلّعها هي الـ net energy released: النزلة من الـ reactants للـ products.