Problem 69 - Chemistry The Central Science In Si Units

Question

Write the formulas for the following compounds, and indicate the oxidation state of the group 14 element or of boron in each: (a) silane, (b) germanium dichloride, (c) tin(II) sulfide, \((\mathbf{d})\) sodium borohydride, \((\mathbf{e})\) lead(IV) nitrate, \((\mathbf{f})\) tin dioxide.

Step-by-Step Solution

Answer

(a) SiH4 (+4), (b) GeCl2 (+2), (c) SnS (+2), (d) NaBH4 (-3 for B), (e) Pb(NO3)4 (+4), (f) SnO2 (+4).

Step 1: Formula for Silane

Silane is a compound of silicon and hydrogen. The chemical formula for silane is \( \text{SiH}_4 \). Silicon in silane is in the oxidation state of +4.

Step 2: Formula for Germanium Dichloride

Germanium dichloride is composed of germanium and chlorine. The chemical formula is \( \text{GeCl}_2 \). In germanium dichloride, germanium has an oxidation state of +2.

Step 3: Formula for Tin(II) Sulfide

Tin(II) sulfide consists of tin and sulfur. The formula is \( \text{SnS} \). Tin in this compound is in the oxidation state +2.

Step 4: Formula for Sodium Borohydride

Sodium borohydride consists of sodium, boron, and hydrogen. The chemical formula is \( \text{NaBH}_4 \). Boron in sodium borohydride has an oxidation state of -3.

Step 5: Formula for Lead(IV) Nitrate

Lead(IV) nitrate is composed of lead and nitrate ions. The chemical formula is \( \text{Pb(NO}_3)_4 \). Lead in this compound is in the oxidation state +4.

Step 6: Formula for Tin Dioxide

Tin dioxide is a compound of tin and oxygen. Its formula is \( \text{SnO}_2 \). Tin in tin dioxide has an oxidation state of +4.

Key Concepts

Oxidation States

Understanding oxidation states is crucial for determining how atoms combine to form compounds. An oxidation state, or oxidation number, reflects the loss or gain of electrons by an atom in a compound. It represents the charge an atom would have if all bonds were ionic in nature.

• A positive oxidation state indicates that an atom has lost electrons.
• A negative oxidation state signifies a gain of electrons.

For example, in silane \(\text{SiH}_4\), silicon has an oxidation state of +4, meaning it has lost four electrons or is effectively contributing four electrons to the hydrogen atoms. Mastering oxidation states helps in understanding the bonding and the chemical behavior of elements in compounds.

Group 14 Elements

Group 14 elements, often referred to as the carbon group, include carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead (Pb). These elements have unique properties and oxidation states that influence their chemical behavior.

• Carbon is well-known for forming complex organic compounds.
• Silicon is used widely in electronics and forms compounds like silane \(\text{SiH}_4\).
• Germanium, found in \(\text{GeCl}_2\), is useful in semiconductors.
• Tin forms several useful compounds such as tin(II) sulfide \(\text{SnS}\) and tin dioxide \(\text{SnO}_2\).
• Lead is recognized for forming compounds like lead(IV) nitrate \(\text{Pb(NO}_3)_4\).

The oxidation states of these elements can vary, allowing them to form a variety of compounds and play a significant role in both organic and inorganic chemistry.

Inorganic Compounds

Inorganic compounds typically consist of a combination of metals and nonmetals, forming ionic or covalent bonds. They are not generally derived from living organisms, unlike organic compounds which mainly consist of carbon. Examples of inorganic compounds from the exercises include:

• Silane \(\text{SiH}_4\), which is covalent and used in hydrogenation processes.
• Germanium dichloride \(\text{GeCl}_2\), useful in materials science.
• Sodium borohydride \(\text{NaBH}_4\), a reducing agent in chemistry.
• Tin dioxide \(\text{SnO}_2\), employed in ceramics and electronics.

Understanding inorganic compounds is fundamental in fields such as materials science, catalysis, and environmental chemistry.

Chemical Nomenclature

Chemical nomenclature is the system of naming chemical compounds using established rules. It ensures clarity and uniformity across the scientific community. There are some fundamental rules to keep in mind:

• Binary compounds of hydrogen are usually named with "hydrogen" appearing first, as seen with silane \(\text{SiH}_4\).
• The name of a metallic element precedes nonmetals in compounds, like in germanium dichloride \(\text{GeCl}_2\).
• If an element can have multiple oxidation states, its oxidation state is indicated in Roman numerals, such as tin(II) sulfide \(\text{SnS}\).
• For polyatomic ions like nitrate in lead(IV) nitrate \(\text{Pb(NO}_3)_4\), the ionic name takes precedence in the compound name.

Mastering chemical nomenclature aids in communication and understanding within chemistry, ensuring that all scientists "speak the same language" when referring to compounds.