Question

Calculate the molecular weights for nh3 and sf6

Answer 1

no.of moles of SF6 = 0.35/molar mass of SF6 = 0.35/146.06 = 2.396 X 10^-3  

so you need 2.396 X 10^-3 moles of NH3 molecules 

molar mass of NH3 = 17.031 g/mole 

that means 1 mole of NH3 = 17.031 g 

so 2.396 X 10^-3 moles of NH3 = 17.031 X 2.396 X 10^-3 = 0.041 g

Answer 2

Answer:

a) $NH_{3}$ = 17 g/mol

b) $SF_{6}$ = 146 g/mol

Explanation:

The molecular weight of a compound is equal to the sum of the atomic weights of the constituent elements.

a) $NH_{3}$

Atomic weight of N = 14 g/mol

Atomic weight of H = 1 g/mol

Molecular weight = $14\ g/mol + 3(1\ g/mol) = 14 + 3 = 17\ g/mol$

b) $SF_{6}$

Atomic weight of S = 32 g/mol

Atomic weight of F = 19 g/mol

Molecular weight = $32\ g/mol + 6(19\ g/mol) = 32 + 114 = 146\ g/mol$