[Borek]

i still dont understand why teh mass of sulfur increaseed

So we are back at the beginning. Because the solution (in which naphthalene is a solvent) contains not atomic sulfur (S₁, molar mass 32) but molecules of sulfur (S₈, molar mass 8*32). You are determining molar mass of the DISSOLVED substance, and this dissolved substance is MOLECULAR sulfur.

[needhelp22]

okay i understand that, only question i have left is why it should be 250/ s8, any specific reason or is that just the way experimenst ahve gone in the past

[Borek]

S₈ is confirmed experimentally on many occasions. Just like O₂ is O₂ and H₂O is H₂O.