suppose 10 g of sulfur is reacted with 48 g of fluorine gas to make SF6, and after the reaction is complete, the temperature in the flask is 125 C.

Question

Find the partial pressure of SF6 in the flask and the mole fraction of SF6 in the 6L flack after the reaction is complete.

Answer 1

S + 3F2 ==> SF6
moles S = 10/32.066 = ??
moles F2 = 48/38 = ??
S is used completely, 0.312 mole SF6 is formed and moles F2-moles used = moles F2 remaining un-reacted.
Use PV = nRT to solve for partial pressure SF6 and again for partial pressure F2 un-reacted.

moles fraction SF6 = moles SF6/total moles.