DrBob222P

Probably close to that of water. 4.184 J/g*K or 1 cal/g/*K

Look up that equation, nEF = -lnK (I'm not at home and can't confirm that equation so check it out) but that is the one you want to use.

moles Ni = 5.2 x 10^15/6.022 x 10^23 = ?? moles Ni = g/atomic mass. You have moles Ni from above and you can look up the atomic mass NI from the periodic table. That leaves just one unknown, grams.

Convert 26.4 g F2 to moles. moles = gfams/mola mass. Then use PV = nRT. Don't forget to use T in Kelvin. Standard P is 1 atm and standard T is 273 K. Solve for V ( in liters).

It depends to a large extent upon what devices you use to measure (crude wooden meter stick or something with a vernier scale) versus the kind of balance used to measure the loss in weight).