You're welcome!!! (De res!!) Well, the "s" in the end of a word is always pronunced (or almost, I can't think of any where it doesn't). For example: sents, véns, pis, Neus.
The "c" sounds always "k" in the end of a word, but there's also the "ç", that sounds "s" at the end of a word. The rules for the "c" pronunciations are: before -e or -i it sounds "s", and before -a, -o and -u it sounds "k", but you can also got it to sound like an "s" putting a "ç" instead of a "c". For example: dic or visc, like -k, but Vicenç or braç, like -"s". cinema or Cèlia -like an "s", but coure or Carme, like a "k" ·the change c/ç: in the verb "començar" -to begin- you put on letter or the other in diferent tenses and persons: "comences" or "començaves".
The "c" after an "n" in the end of a word sounds just like when it happens when in English there's an "n" followed by a "g": For exapmple: cinc -five- or banc -bank- sound just like in beiNG.
About the "g", it sounds like a "j" (juice) before -e and -i, but like "g" (get) before -a, o- or -u, and you can also got this sound putting a "u" (which is silent if there aren't thumbs -that's "¨", right?- on it) between the "g" and the -e or the -i. gel, or ginesta, like "j" gas or guants, like "g" Guimerà and guerra, like "g" and the "u" is silent Paraigua, pingüí, aigüera, the "g" like in get and the the "u" also sounds.
The same happens with the "q": it is always followed by a "u", but it doesn't sound before -e and -i, at least there are thumbs on it. Queralt or Quim, the "q" is like "k" but the "u" is silent aquàtic, aqüífer, the "u" is pronunced.