Which property is characteristic of alkenes, alkynes, and aromatic hydrocarbons?
a. their vapor pressures decrease as their size increases.
b. their ph values are greater than 7.
c. their densities are lower than the density of water.
d. they are soluble in water.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.