What is the molar mass of Mn2Se7 ? A.) 601.34 g/mol

B.) 542.50 g/mol

C.) 662.60 g/mol

C.  662.60

Explanation:

the mass of Mn is about 54 grams/mol, (multiply that by 2 since there are 2 Mn's).

the mass of Se is about 79 grams/mol, so multiply that by 7

if you add them, you get 662.60 (approxamitly)

C) 662.60

Explanation:

~~55*2 + 79*7 = 110 + 553 = 663 (~~662.60)

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.

give me abc and i will get it for u.