Skip to main content
Ch.3 - Molecules and Compounds
Tro - Chemistry: A Molecular Approach 6th Edition
Tro6th EditionChemistry: A Molecular ApproachISBN: 9780137832217Not the one you use?Change textbook
All textbooksTro 6th EditionCh.3 - Molecules and CompoundsProblem 82
Chapter 3, Problem 82

Iron in the earth is in the form of iron ore. Common ores include Fe2O3 (hematite), Fe3O4 (magnetite), and FeCO3 (siderite). Calculate the mass percent composition of iron for each of these iron ores. Which ore has the highest iron content?

Verified step by step guidance
1
Identify the chemical formula of each iron ore: Fe2O3, Fe3O4, and FeCO3.
Calculate the molar mass of each compound using the atomic masses: Fe (55.85 g/mol), O (16.00 g/mol), and C (12.01 g/mol).
Determine the total mass of iron in one mole of each compound by multiplying the number of iron atoms by the atomic mass of iron.
Calculate the mass percent composition of iron in each ore using the formula: (mass of iron in the compound / molar mass of the compound) * 100%.
Compare the mass percent compositions to determine which ore has the highest iron content.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Mass Percent Composition

Mass percent composition is a way to express the concentration of an element in a compound as a percentage of the total mass of that compound. It is calculated by dividing the mass of the element by the total mass of the compound and multiplying by 100. This concept is essential for determining how much of a specific element, like iron, is present in various iron ores.

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all the atoms in a chemical formula. Understanding molar mass is crucial for calculating mass percent composition, as it provides the necessary total mass of the compound for the calculations.
Recommended video:
Guided course
02:11
Molar Mass Concept

Chemical Formula Interpretation

Interpreting chemical formulas involves understanding the ratios of different elements in a compound. For example, in Fe2O3, there are two iron (Fe) atoms and three oxygen (O) atoms. This knowledge is vital for calculating the mass percent of iron in each ore, as it allows for the correct identification of the number of iron atoms relative to the total mass of the compound.
Recommended video:
Guided course
03:13
Intepreting the Band of Stability
Related Practice
Textbook Question

Most fertilizers consist of nitrogen-containing compounds such as NH3, CO(NH2)2, NH4NO3, and (NH4)2SO4. Plants use the nitrogen content in these compounds for protein synthesis. Calculate the mass percent composition of nitrogen in CO(NH2)2.

1368
views
Textbook Question

Copper(II) fluoride contains 37.42% F by mass. Calculate the mass of fluorine (in g) in 23.8 g of copper(II) fluoride.

Textbook Question

Calculate the mass percent composition of nitrogen in each nitrogen-containing compound. c. NO2

2162
views
1
rank
Textbook Question

Write a ratio showing the relationship between the molar amounts of each element for each compound. (See Appendix IIA for color codes.) (b)

489
views
Textbook Question

Calculate the mass percent composition of nitrogen in each nitrogen-containing compound. a. N2O b. NO

677
views
1
rank
Textbook Question

The iodide ion is a dietary mineral essential to good nutrition. In countries where potassium iodide is added to salt, iodine deficiency (or goiter) has been almost completely eliminated. The recommended daily allowance (RDA) for iodine is 150 mg/day. How much potassium iodide (76.45% I) should you consume if you want to meet the RDA?

1365
views