How many moles is 5.70x10^23 molecules of NH3?

0.95mol

Explanation:

1mole of NH3 contains 6.02x10^23 molecules

Therefore, Xmol of NH3 will contain 5.70x10^23 molecules i.e

Xmol of NH3 = (5.70x10^23) /6.02x10^23 = 0.95mol

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.

the answer would be b i believe