Question

Name these hydrates: (a) \(\mathrm{MgNH}_{4} \mathrm{PO}_{4} \cdot 6 \mathrm{H}_{2} \mathrm{O}\) (b) \(\mathrm{FeSO}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O}\) (c) \(\mathrm{SnCl}_{4} \cdot 5 \mathrm{H}_{2} \mathrm{O}\)

Short answer

(a) Magnesium ammonium phosphate hexahydrate. (b) Iron(II) sulfate heptahydrate. (c) Tin(IV) chloride pentahydrate.

Step-by-step solution

Identify the Anhydrous Compound - Part (a)

Determine the name of the anhydrous compound \(\mathrm{MgNH}_{4} \mathrm{PO}_{4}\). It is magnesium ammonium phosphate.

Determine Hydration Number - Part (a)

Identify the number of water molecules attached to the compound. Here, it is \(6\ \mathrm{H}_{2}\mathrm{O}\). This makes it a hexahydrate.

Combine the Names - Part (a)

Combine the name of the anhydrous compound with the hydration number: Magnesium ammonium phosphate hexahydrate.

Identify the Anhydrous Compound - Part (b)

Determine the name of the anhydrous compound \(\mathrm{FeSO}_{4}\). It is iron(II) sulfate.

Determine Hydration Number - Part (b)

Identify the number of water molecules attached to the compound. Here, it is \(7\ \mathrm{H}_{2}\mathrm{O}\). This makes it a heptahydrate.

Combine the Names - Part (b)

Combine the name of the anhydrous compound with the hydration number: Iron(II) sulfate heptahydrate.

Identify the Anhydrous Compound - Part (c)

Determine the name of the anhydrous compound \(\mathrm{SnCl}_{4}\). It is tin(IV) chloride.

Determine Hydration Number - Part (c)

Identify the number of water molecules attached to the compound. Here, it is \(5\ \mathrm{H}_{2}\mathrm{O}\). This makes it a pentahydrate.

Combine the Names - Part (c)

Combine the name of the anhydrous compound with the hydration number: Tin(IV) chloride pentahydrate.

Key concepts

Anhydrous Compounds

Anhydrous compounds are substances that do not contain water molecules within their chemical structure. In chemistry, the term 'anhydrous' means 'without water'.
These compounds are important as they are often used as starting materials to create hydrates – compounds that incorporate water molecules into their structure. Identifying the anhydrous form of a compound helps you understand the basics before addressing more complex structures like hydrates.
In the given exercise, the compounds magnesium ammonium phosphate (\(\text{MgNH}_4 \text{PO}_4\)), iron(II) sulfate (\(\text{FeSO}_4\)), and tin(IV) chloride (\( \text{SnCl}_4 \)) are the anhydrous forms. Once you know these, you add their hydration numbers to name the full hydrate.

Hydration Number

The hydration number refers to the number of water molecules chemically bonded to an anhydrous compound in a hydrate.
These water molecules are locked within the crystal structure of the compound. The hydration number is crucial in naming hydrates as it indicates how many water molecules are present.
For instance:
* Magnesium ammonium phosphate with 6 water molecules becomes a hexahydrate.
* Iron(II) sulfate with 7 water molecules turns into a heptahydrate.
* Tin(IV) chloride with 5 water molecules is called a pentahydrate.
This shows the role of hydration number in specifying the correct name for the hydrate.

Chemical Nomenclature

Chemical nomenclature, or the system of naming chemical compounds, is essential for clear and accurate communication in the scientific community.
Naming hydrates involves a specific set of rules. You must first identify the anhydrous compound name and then add a suffix indicating the number of water molecules.
For examples:
* \(\text{MgNH}_4\text{PO}_4 \) becomes magnesium ammonium phosphate, and coupled with 6 water molecules, it is named magnesium ammonium phosphate hexahydrate.
* \(\text{FeSO}_4\) transforms into iron(II) sulfate and with 7 water molecules, it's iron(II) sulfate heptahydrate.
* \(\text{SnCl}_4\) is tin(IV) chloride and with 5 water molecules, it becomes tin(IV) chloride pentahydrate.
Understanding this nomenclature helps in the clear identification of compounds and in conveying detailed chemical information.

Inorganic Chemistry

Inorganic chemistry deals with compounds that are not primarily based on carbon atoms. This branch of chemistry covers metals and minerals, including the study of anhydrous compounds and hydrates.
Hydrates are critical in many fields, such as pharmaceuticals, agriculture, and construction. They can affect the physical properties, reactivity, and stability of compounds.
To study inorganic chemicals, you need to understand key concepts like anhydrous compounds and hydration numbers, and how they are named through chemical nomenclature. This helps in identifying the compounds' roles in different industries and research areas.
For example, the knowledge of hydrates can help in understanding processes like hydration in cement, where specific water molecules play a role in setting and hardening.