Problem 34 - Chemistry The Science in Context

Question

Determine the molar masses of the following minerals: a. rhodonite, \(\mathrm{MnSiO}_{3}\) b. scheelite, CaWO \(_{4}\) c. ilmenite, FeTiO \(_{3}\) d. magnesite, \(\mathrm{Mg} \mathrm{CO}_{3}\)

Step-by-Step Solution

Answer

Question: Determine the molar masses of the following minerals: a. Rhodonite: MnSiO3 b. Scheelite: CaWO4 c. Ilmenite: FeTiO3 d. Magnesite: MgCO3 Answer: a. Rhodonite: 131.03 g/mol b. Scheelite: 287.92 g/mol c. Ilmenite: 151.72 g/mol d. Magnesite: 84.32 g/mol

Step 1: Identify the elements in the mineral and their atomic masses

To find the atomic masses of the elements in the minerals, use the periodic table. Remember that the atomic masses are usually listed below the element symbol and have units of atomic mass units (amu). a. Rhodonite, \(\mathrm{MnSiO}_{3}\) => Mn (Manganese), Si (Silicon), O (Oxygen) b. Scheelite, \(\mathrm{CaWO}_{4}\) => Ca (Calcium), W (Tungsten), O (Oxygen) c. Ilmenite, \(\mathrm{FeTiO}_{3}\) => Fe (Iron), Ti (Titanium), O (Oxygen) d. Magnesite, \(\mathrm{MgCO}_{3}\) => Mg (Magnesium), C (Carbon), O (Oxygen)

Step 2: Determine the atomic masses of the elements

Using a periodic table, find the atomic masses of the elements found in Step 1. a. Mn: 54.94 amu, Si: 28.09 amu, O: 16.00 amu b. Ca: 40.08 amu, W: 183.84 amu, O: 16.00 amu c. Fe: 55.85 amu, Ti: 47.87 amu, O: 16.00 amu d. Mg: 24.31 amu, C: 12.01 amu, O: 16.00 amu

Step 3: Calculate the molar masses of the minerals

Now, using the atomic masses of the elements, calculate the molar mass for each mineral by adding up the atomic masses of the constituent elements, taking into account the stoichiometry of the chemical formula. a. Rhodonite: \(\mathrm{MnSiO}_{3}\) => 54.94 (Mn) + 28.09 (Si) + 3 * 16.00 (O) = 131.03 g/mol b. Scheelite: \(\mathrm{CaWO}_{4}\) => 40.08 (Ca) + 183.84 (W) + 4 * 16.00 (O) = 287.92 g/mol c. Ilmenite: \(\mathrm{FeTiO}_{3}\) => 55.85 (Fe) + 47.87 (Ti) + 3 * 16.00 (O) = 151.72 g/mol d. Magnesite: \(\mathrm{MgCO}_{3}\) => 24.31 (Mg) + 12.01 (C) + 3 * 16.00 (O) = 84.32 g/mol So, the molar masses of the given minerals are as follows: a. Rhodonite: 131.03 g/mol b. Scheelite: 287.92 g/mol c. Ilmenite: 151.72 g/mol d. Magnesite: 84.32 g/mol

Key Concepts

Understanding Atomic Mass

Atomic mass is a fundamental concept in chemistry that refers to the mass of an atom, usually expressed in atomic mass units (amu). It's basically the sum of protons and neutrons inside the nucleus of an atom. You can find the atomic mass of each element on the periodic table, usually listed under the element's symbol.

• For example, the atomic mass of manganese (Mn) is 54.94 amu.
• Silicon (Si) has an atomic mass of 28.09 amu.

Understanding atomic mass is crucial for calculating the molar mass of compounds, as it tells you how much one mole of atoms weighs, which in turn helps you in various chemical calculations.
This is a key building block for determining how substances behave and react with each other.

Deciphering Chemical Formulas

A chemical formula is a concise way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound. Each element is represented by its chemical symbol and is followed by a number that indicates how many atoms of that element are present.

• For instance, in rhodonite ( MnSiOet천 오etyetetet), the formula tells us that one molecule contains one manganese (Mn) atom, one silicon (Si) atom, and three oxygen (O) atoms.

Understanding a chemical formula is crucial for calculating molar mass. You need to know the number of atoms for each element within the compound, which will directly affect your calculations.
Mastering this concept helps in both theoretical studies and practical lab work.

Navigating the Periodic Table

The periodic table is a comprehensive chart that organizes all known elements based on their atomic number, electron configuration, and recurring chemical properties. It's an essential tool for chemists and students alike, offering a treasure trove of information at a glance.
Each element's atomic mass (used in molar mass calculation) can be found here.

• For example, to find the elements within scheelite ( CaWOet천 오etetet), you can locate calcium (Ca), tungsten (W), and oxygen (O) on the table along with their respective atomic masses.

Knowing how to effectively use the periodic table allows you to quickly identify the characteristics of each element, which is crucial for understanding chemical compounds and reactions.
Being adept at this makes chemistry much more intuitive and manageable.

Investigating Mineral Composition

Mineral composition refers to the particular combination and proportions of elements and compounds that make up a mineral. Each mineral has a unique structure and chemical formula that define its properties and uses in various applications.

• For instance, ilmenite ( FeTiO 네etetet) is composed of iron (Fe), titanium (Ti), and oxygen (O).

Understanding mineral composition is important not only in chemistry but also in geology and materials science, where the properties of a mineral must be fully understood for its application and extraction.
This knowledge enables scientists and engineers to optimize resources and industrial processes.