علل سبب كتابة الهمزة مدا في كلمة آمال

The reason for writing the hamza letter “مدا” in the word “آمال” is because the hamza is followed by an open hamza for the purposes of grammatical declension on a verb pattern. Two hamzas cannot be written together in Arabic writing, so they were merged and written as “مدًا” instead.