La composicion centesimal encontrada para una sustancia es c = 40% h = 6, 4% y o = 53, 6% si la masa molecular debla sustancia es 90 gramoab¿cualbesvsu formula molecular , ?

1. calcular moles

C : 40 g / 12 g / mol = 3.

33 mol

H : 6.

4 g / 1 g / mol = 6.

4 mol

O : 53.

6 g / 16 g / mol = 3.

35 mol

2.

Dividir entre el menor de los resultados

C : 3.

33 mol / 3.

33 mol = 1

H : 6.

4 mol / 3.

33 mol = 2

O : 3.

35 mol / 3.

33 mol = 1

3.

F Empírica : CH2O

4.

Calcular Mm de la FE

C : 1 x 12 = 12 g / mol

H : 2 x 1 = 2 g / mol

O : 1 x 16 = 16 g / mol

`````````````````````````````` Mm = 30 g / mol

5.

Calcular n

n = Mm del compuesto ``````````````````````````` Mm de la FE

n = 90 g / mol / 30 g / mol

n = 3

6.

FM = (CH2O)n = (CH2O)₆ = C₆H₁₂O₆.