Respuesta :

Answer:

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)

Answer:

C) 662.60

Explanation:

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

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