Question

Write chemical formulas for the following minerals: (a) calcite, (b) dolomite, (c) fluorite, (d) halite, (e) corundum, (f) magnetite, (g) beryl, (h) galena, (i) epsomite, (j) anhydrite.

Short answer

(a) CaCO₃, (b) CaMg(CO₃)₂, (c) CaF₂, (d) NaCl, (e) Al₂O₃, (f) Fe₃O₄, (g) Be₃Al₂Si₆O₁₈, (h) PbS, (i) MgSO₄·7H₂O, (j) CaSO₄.

Step-by-step solution

Understand Mineral Composition Concepts

Minerals are naturally occurring substances with a definitive chemical composition. To write the chemical formula for a mineral, you need to know the elements it consists of and their respective ratios.

Formula for Calcite

Calcite primarily consists of calcium carbonate. Its chemical formula is \( \text{CaCO}_3 \). The calcite structure involves calcium, carbon, and oxygen.

Formula for Dolomite

Dolomite is a mineral made up of calcium magnesium carbonate with a formula \( \text{CaMg(CO}_3)_2 \). It has both calcium and magnesium in its structure.

Formula for Fluorite

Fluorite is composed of calcium fluoride. The chemical formula for fluorite is \( \text{CaF}_2 \), signaling that it contains calcium and fluorine.

Formula for Halite

Halite is the mineral form of sodium chloride, also known as rock salt. Its chemical formula is \( \text{NaCl} \), indicating it consists of sodium and chlorine.

Formula for Corundum

Corundum is made up of aluminum oxide. The formula for corundum is \( \text{Al}_2\text{O}_3 \), showing its composition of aluminum and oxygen.

Formula for Magnetite

Magnetite consists of iron oxide and its chemical formula is \( \text{Fe}_3\text{O}_4 \). This indicates a combination of iron and oxygen in its structure.

Formula for Beryl

Beryl is composed of beryllium aluminum silicate. The formula for beryl is \( \text{Be}_3\text{Al}_2\text{Si}_6\text{O}_{18} \), which includes beryllium, aluminum, silicon, and oxygen.

Formula for Galena

Galena is characterized by being a lead sulfide mineral. Its formula is \( \text{PbS} \), which consists of lead and sulfur.

Formula for Epsomite

Epsomite is commonly known as Epsom salt and its formula is \( \text{MgSO}_4 \cdot 7 \text{H}_2\text{O} \). This shows it contains magnesium, sulfur, oxygen, and water.

Formula for Anhydrite

Anhydrite, unlike its cousin gypsum, lacks water and is composed of calcium sulfate. The formula is \( \text{CaSO}_4 \), showing calcium, sulfur, and oxygen.

Key concepts

Mineral Composition

Minerals are naturally occurring substances with definite chemical compositions, and understanding their formation is crucial for chemistry and geology. Each mineral is made up of a combination of elements, brought together in specific ratios to form a unique chemical formula. Knowing this helps identify and classify minerals effectively.

Understanding mineral composition involves recognizing:

• Key elements present in the mineral
• The ratio of these elements
• Physical properties that result from their composition

By understanding these components, you can determine the formula of a mineral, giving insights into its structure and properties.

Calcium Carbonate

Calcium carbonate is a common mineral found in a variety of forms such as calcite and aragonite. Its chemical formula is written as \( \text{CaCO}_3 \). This compound consists of calcium \( \text{Ca} \), carbon \( \text{C} \), and three oxygen atoms \( \text{O}_3 \).

Some essential features of calcium carbonate include:

• Serving as a major component of rocks such as limestone
• Being utilized extensively in the construction industry
• Playing a crucial role in the formation of shells and skeletons in marine organisms

Recognizing its chemical formula helps in understanding not only geological processes but also its practical applications in multiple industries.

Iron Oxide

Iron oxide is a chemical compound composed of iron and oxygen. Various forms exist, the most common being hematite and magnetite. In the case of magnetite, its formula is \( \text{Fe}_3\text{O}_4 \).

Iron oxide has several critical characteristics:

• Widely used as pigments in paints and coatings
• Key component in scientific and catalytic applications
• Forms naturally on Earth as well as on the surface of Mars, indicating past water presence

This compound showcases the versatility and importance of chemical composition in both natural and industrial contexts.

Aluminum Oxide

Aluminum oxide, or alumina, is an oxide of aluminum with the chemical formula \( \text{Al}_2\text{O}_3 \). It forms the basis of the mineral corundum, which, when impurities are present, gives rise to precious stones like sapphires and rubies.

Some key attributes include:

• High melting point which makes it suitable for use as a refractory material
• Utilization as an abrasive due to its hardness
• Widely used in the manufacturing of aluminum metal

This compound's presence in diverse applications highlights its importance in both natural and industrial settings, reinforcing the significance of chemical formulas in understanding material properties.