Learn Portuguese (Portugal): O senhor traria o champanhe ao quarto? - Would you bring the champagne to the room?

It is the conditional tense of trazer (to bring). While most verbs in the conditional just add endings directly to the full infinitive, trazer is irregular. It drops the -ze- and uses the shortened stem trar-. Then we add the ending -ia for the o senhor form, making traria.

Why use o senhor to mean 'you' in this context?

In European Portuguese, o senhor is the standard, polite way to address a man you don't know well. In a formal service setting like a hotel, it is much safer and more polite than using você.

Why does the sentence use ao quarto instead of para o quarto?

Both mean 'to the room', but the preposition a often implies a quick or temporary action, like a waiter dropping off a bottle. Ao is the mandatory contraction of a (to) + o (the). Using para would also be understood, but it generally implies moving somewhere to stay there longer.

Is champanhe a masculine word?

Yes, it is masculine, which is why it takes the article o (o champanhe). Words ending in -e do not have a strict gender rule in Portuguese, so it is always a good idea to memorize them along with their matching article.