Good Riddles

Question: If 1+1=2, 2+2=8, 3+3=18. What does 4+4=?

Question: What can you smell but not see. And can be deadly, too.

Question: What is red and white at home, but can never be that when it leaves?

Question: I can be seen and heard miles away, only show my position for a couple of seconds, but if touched it can kill you instantly.

Question: Bob is dead in the INSIDE of his apartment. There is a puddle of water, a ball, some glass, and a broken window How did Bob die? What is Bob?