Which pair shares the same empirical formula? C2H4 and C6H6 C6H6 and C3H3 CH2 and C6H6 CH and C2H4

Harvey kept a balloon with a volume of 348 milliliters at 25.0˚c inside a freezer for a night.  when he took it out, its new volume was 322 milliliters, but its pressure was the same.  if the final temperature of the balloon is the same as the freezer’s, what is the temperature of the freezer? the temperature of the freezer is  kelvins.

For the following, determine the type of reaction and then give products.

What is the enthalpy of combustion (per mole) of c4h10 (g)? –2,657.5 kj/mol –5315.0 kj/mol –509.7 kj/mol –254.8 kj/mol