Question

Question 8 If the mass percentage composition of a compound is 72.1% Mn and 27.9% O, its empirical formula is Selected Answer: Correct Answer. D. Mn304 D. Mn304

Answer 1

The empirical formula of a compound with 72.1% Mn and 27.9% O is MnO.

Step-by-step explanation:

The empirical formula of a compound can be determined based on its mass percentage composition of different elements. In this case, the compound is composed of 72.1% Mn (manganese) and 27.9% O (oxygen).

To find the empirical formula, we need to consider the relative number of atoms in the compound. Assuming we have 100g of the compound, we have 72.1g of Mn and 27.9g of O.

Using the molar masses of Mn (54.938 g/mol) and O (15.999 g/mol), we can calculate the number of moles of each element:

1. Moles of Mn = 72.1g / 54.938 g/mol = 1.314 mol
2. Moles of O = 27.9g / 15.999 g/mol = 1.744 mol

Now, we divide the number of moles by the smallest value to get the mole ratio:

1. Mn:O = 1.314 mol / 1.314 mol = 1:1
2. O:Mn = 1.744 mol / 1.314 mol = 1.326:1

Since we want whole-number ratios, we round the ratios to the nearest whole number:

1. Mn:O = 1:1

Therefore, the empirical formula of the compound with 72.1% Mn and 27.9% O is MnO.

Answer 2

The compound is
`Mn_(3)O_(4)`

Step-by-step explanation:

The mass percentage of Mn is 72.1% and the mass percentage of O is 27.9%.

The mass percentage of a compound is given by:

`percentage_(A)=(n*MM_(A))/(MM_(C)) *100`

where:

n is its coefitient in the compund formula

MMa=Molar mass of the element A

MMc=Molar mass of the compound

So, we can figure out which compound is by dividing the percentage by its molar mass

Mn=72.1÷54.938045=1.31239

O=27.9÷15.9994=1.74382

Then, we divide each result by the smaller one (Mn)

Mn=1.31239÷1.31239=1

O=1.74382÷1.31239=1.3287

Each the realation of Mn:O is 1:1.3287

Then we multiply each result by 3:

Mn=1×3=3

O=1.3287×3=3.986≈4

Finally we figure out that the compound has 3 atoms of Mn and 4 atoms O. Result=
`Mn_(3)O_(4)`

Mn3O4 is sometimes used as a starting material in the production of soft ferrites e.g. manganese zinc ferrite, and lithium manganese oxide, used in lithium batteries.