Calculate the molecular formula of a compound with the empirical formula c5h11 and a molar mass of 142.32 grams/mole

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer