no, hes only pretending to be. Snape became an ally to Dumbledore when lily potter died, because he loved her ever since they were kids :'(
no. in the 6th snape kills dumbledore. in the 7th, voldemort kills snape and harry kills voldemort
Voldemort didn't know Snape had changed sides, Snape was a spy.
No. Lord Voldemort killed Severus Snape's true love.
Yes. Well, actually, technically, Nagini (Voldemort's giant snake) killed Snape. But Voldemort told the snake to do it.
Because voldemort thinks that snape is the master of the elder wand but he isn't.
Yes and No. Right before the fall of the Potters and Voldemort, Snape switched to being in the service of Dumbledore. After Voldemort fell, Snape was used by Dumbledore to keep a lookout in case of Voldemort's return, as well as to keep an eye on the remaining Death Eaters not in jail. Once Voldemort returned, Dumbledore had Snape serve Voldemort, yet he was to rely the info back to Dumbledore. Snape being a servant of Dumbledore is very easy to miss in the books and the movies. In the Half Blood Prince, when Snape kills Dumbledore, it was due to the fact the Dumbledore had arranged for Snape to kill him, if Harry was to kill Voldemort.
Not at all.
Voldemort kills Snape to get the elder wand
Voldemort ordered his snake, Nagini, to kill Severus Snape.
Tobias Snape (Snape's father) or Lilly or I think voldemort
Voldemort killed Snape.
Severus Snape was on Peter Pettigrew's "side" for a short amount of time. As you probably know, Snape was a true Death Eater and worker for Voldemort for a short amount of time. Snape was a Death Eater for Voldemort until he found out that Voldemort was after the Potter family. Snape immediately went back to Dumbeldore and asked for forgiveness. From then on Snape became a double agent, meaning he worked for Dumbeldore and Voldemort, he told Voldemort false news about "Dumbeldore's Side" and true news to Dumbeldore. Because Pettigrew was on Voldemort's side for a while, he was on at the same time as Snape, but only for about a month or so.