Question

Obtener la fórmula empírica de un compuesto cuya composición centesimal reporta: Cr: 26,53 % , S: 24,52 % y O: 48,96%. Dato: m.A. [Cr= 52 , S= 32]

Answer 1

Answer: The empirical formula of the compound becomes
`Cr_2S_3O_(12)`

Step-by-step explanation:

The empirical formula is the chemical formula of the simplest ratio of the number of atoms of each element present in a compound.

Let the mass of the compound be 100 g

Given values:

% of Cr = 26.53%

% of S = 24.52%

% of O = 48.96%

Mass of Cr = 26.53 g

Mass of S = 24.52 g

Mass of O = 48.96 g

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

`\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}` ......(1)

To formulate the empirical formula, we need to follow some steps:

• Step 1: Converting the given masses into moles.

Molar mass of Cr = 52 g/mol

Molar mass of S = 32 g/mol

Molar mass of O = 16 g/mol

Putting values in equation 1, we get:

`\text{Moles of Cr}=(26.53g)/(52g/mol)=0.510 mol`

`\text{Moles of S}=(24.52g)/(32g/mol)=0.766 mol`

`\text{Moles of O}=(48.96g)/(16g/mol)=3.06 mol`

• Step 2: Calculating the mole ratio of the given elements.

Calculating the mole fraction of each element by dividing the calculated moles by the least calculated number of moles that is 0.510 moles

`\text{Mole fraction of Cr}=(0.510)/(0.510)=1`

`\text{Mole fraction of S}=(0.766)/(0.510)=1.5`

`\text{Mole fraction of O}=(3.06)/(0.510)=6`

Multiplying the mole fraction of all the elements by 2, in order to make it as a whole number

`\text{Mole fraction of Cr}=(2* 1)=2`

`\text{Mole fraction of S}=(2* 1.5)=3`

`\text{Mole fraction of O}=(2* 6)=12`

• Step 3: Taking the mole ratio as their subscripts.

The ratio of Cr : S : O = 2 : 3 : 12

Hence, the empirical formula of the compound becomes
`Cr_2S_3O_(12)`

Answer 2

Respuesta:

Cr₂S₃O₁₂

Explicación:

Primer paso: Dividir el porcentaje en masa de cada elemento por su masa atómica

Cr: 26,53/52 = 0,510

S: 24,52/32 = 0,766

O: 48,96/16 = 3,06

Segundo paso: Dividir todos los números por el más pequeño (0,510)

Cr: 0,510/0,510 = 1

S: 0,766/0,510 = 1,5

O: 3,06/0,510 = 6

Tercer paso: Multiplicar todos los números por algún número que haga que todos sean enteros (2)

Cr: 1 × 2 = 2

S: 1,5 × 2 = 3

O: 6 × 2 = 12

La fórmula empírica es Cr₂S₃O₁₂.