Final answer:
The name of the compound is Chromium(III) Nitrate Tetrahydrate, and its formula is Cr(NO3)3·4H2O. In naming ionic compounds, Roman numerals are used to denote the charge of cations with multiple oxidation states.
Step-by-step explanation:
The name of the chromium compound that includes nitrate and is hydrated with four water molecules is Chromium(III) Nitrate Tetrahydrate. The correct formula for this compound is expressed as Cr(NO3)3·4H2O, where 'Cr' stands for chromium, 'NO3' represents the nitrate ion, the number '3' indicates that there are three nitrate ions per chromium ion, and '·4H2O' signifies that there are four water molecules associated with each formula unit (tetrahydrate).
For other named compounds:
- Iron (III) sulfide: Fe2S3
- Copper (II) selenide: CuSe
- Gallium (III) nitride: GaN
- Magnesium sulfate heptahydrate: MgSO4·7H2O
- Titanium (III) sulfate: Ti2(SO4)3
The listed compounds highlight the process of naming ionic compounds, which involves using Roman numerals to indicate the charge on the metal cation when it can adopt more than one charge.