Question

calcula la formula molecular de un compuesto sabiedo que tiene los sgt porsentajes P=30% H=20% O=56% su masa de 720 UMA

Answer 1

Mm P = 30.9 g/mol
       H = 1 g/mol
       O = 16 g/mol

calcular moles de cada elemento

P: 31 g /30.9 g/mol  = 1 mol
H: 20 g / 1 g/mol = 20 mol
O: 48 g / 16 g/mol = 3 mol

dividir entre el menor de los resultados

P: 1 mol / 1 mol = 1
H: 20 mol / 1 mol = 20
O: 3 mol / 1 mol = 3

FE = PH₂₀O₃

MASA MOLECULAR DE LA FE
P: 1 x 30.9  = 30.9 g/mol
H: 20 x 1 g = 20 g/mol
O: 3 x 16 g = 48 g/mol
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           Mm = 98.9 g/mol  ≈ 99 g/mol

n = 720 g/mol / 99 g/mol
n = 7

FM = (FE)n

FM = (PH₂₀O₃)₇

FM = P₇H₁₄₀O₂₁