Questions & Answers about Este percurso é longo?
Because longo is being treated as a characteristic of the route itself, not a temporary condition.
- ser + adjective is commonly used for more inherent qualities: é longo, é curto, é difícil
- estar is usually for temporary states or conditions
So Este percurso é longo? sounds natural for asking whether the route is long in general.
No. In Portuguese, yes/no questions are usually formed just by intonation and a question mark, not by changing the word order.
So:
The structure stays the same.