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Ch.7 Chemical Quantities and Reactions
Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 13th Edition
Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353Not the one you use?Change textbook
Chapter 7, Problem 114a

Ammonium sulfate, (NH4)2SO4, is used in fertilizers to provide nitrogen for the soil.
a. How many formula units are in 0.200 mole of ammonium sulfate?

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1
Step 1: Understand the problem. The goal is to determine the number of formula units in 0.200 mole of ammonium sulfate ((NH₄)₂SO₄). Recall that a mole represents a specific number of particles, known as Avogadro's number, which is approximately 6.022 × 10²³ particles/mole.
Step 2: Write the relationship between moles and formula units. The number of formula units can be calculated using the equation: n=N×A, where n is the number of moles, N is the number of formula units, and A is Avogadro's number.
Step 3: Rearrange the formula to solve for the number of formula units. The equation becomes: N=n×A. Substitute the given value of moles (0.200 mole) and Avogadro's number (6.022 × 10²³ formula units/mole) into the equation.
Step 4: Perform the multiplication. Multiply 0.200 mole by 6.022 × 10²³ formula units/mole to find the total number of formula units.
Step 5: Interpret the result. The calculated value represents the number of formula units of ammonium sulfate in 0.200 mole. Ensure the units are consistent and the result is expressed in scientific notation for clarity.

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Key Concepts

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

Mole Concept

The mole is a fundamental unit in chemistry that quantifies the amount of substance. One mole contains approximately 6.022 x 10²³ entities, such as atoms, molecules, or formula units. This concept is essential for converting between moles and the number of particles in a substance.
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Formula Units

A formula unit represents the simplest ratio of ions in an ionic compound. For ammonium sulfate, (NH₄)₂SO₄, one formula unit consists of two ammonium ions and one sulfate ion. Understanding formula units is crucial for calculating the number of particles in a given amount of a compound.
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Avogadro's Number

Avogadro's number, 6.022 x 10²³, is the number of particles in one mole of a substance. It allows chemists to relate the macroscopic scale of substances to the microscopic scale of atoms and molecules. This number is vital for determining how many formula units are present in a specified number of moles.
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