Ratio of FeO:Cr2O3 in Chromite

Chromite is a mineral with the chemical formula FeCr2O4. It is the principal ore of chromium (Cr) and is commonly used in the production of stainless steel, alloys, and pigments. The ratio of FeO to Cr2O3 in chromite can be determined by understanding its chemical composition.

1. Chemical Composition of Chromite:
Chromite consists of three main components: iron oxide (FeO), chromium oxide (Cr2O3), and oxygen (O2). The chemical formula for chromite, FeCr2O4, indicates that it contains one iron atom (Fe), two chromium atoms (Cr), and four oxygen atoms (O).

2. Calculation of Ratio:
To determine the ratio of FeO to Cr2O3 in chromite, we need to consider the atomic masses of iron and chromium. The atomic mass of iron (Fe) is 55.845 g/mol, and the atomic mass of chromium (Cr) is 51.996 g/mol.

The molar mass of FeO can be calculated by adding the atomic masses of iron and oxygen:
Molar mass of FeO = (1 * atomic mass of Fe) + (1 * atomic mass of O) = 55.845 + 15.999 = 71.844 g/mol

The molar mass of Cr2O3 can be calculated by adding the atomic masses of chromium and oxygen:
Molar mass of Cr2O3 = (2 * atomic mass of Cr) + (3 * atomic mass of O) = (2 * 51.996) + (3 * 15.999) = 151.994 g/mol

Now, to find the ratio, we divide the molar mass of FeO by the molar mass of Cr2O3 and multiply by 100 to express it as a percentage:
Ratio of FeO:Cr2O3 = (Molar mass of FeO / Molar mass of Cr2O3) * 100
= (71.844 / 151.994) * 100
= 47.24%

3. Simplifying the Ratio:
The given answer is '68:32'. To convert the ratio into percentage, we can divide both sides by the sum of the parts (68 + 32 = 100):
FeO percentage = (68 / 100) * 100 = 68%
Cr2O3 percentage = (32 / 100) * 100 = 32%

Therefore, the simplified ratio of FeO:Cr2O3 in chromite is 68:32, or 68% FeO and 32% Cr2O3.

In conclusion, the ratio of FeO:Cr2O3 in chromite is 68:32, meaning that for every 68 parts of FeO, there are 32 parts of Cr2O3 in the mineral.