Textbook Question
What is the mass in grams of each of the following samples? (a) 0.0015 mol of sodium
Ch.3 - Mass Relationships in Chemical Reactions
Chapter 3, Problem 58a
A sample that weighs 25.12 g contains 6.022⨉1023 particles. If 25.00% of the total number of particles are argon atoms and 75.00% are another element, what is the chemical identity of the other constituent?
Verified step by step guidance1
Determine the number of argon atoms by calculating 25.00% of 6.022\times10^{23} particles.
Calculate the number of particles of the other element by subtracting the number of argon atoms from the total number of particles.
Find the molar mass of argon (Ar) using the periodic table, which is approximately 39.95 g/mol.
Calculate the mass of argon in the sample using the number of argon atoms and Avogadro's number.
Subtract the mass of argon from the total mass of the sample to find the mass of the other element, then use the number of particles of the other element to determine its molar mass and identify it using the periodic table.
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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 represents a specific quantity of particles, typically atoms or molecules. One mole contains Avogadro's number, approximately 6.022 x 10^23 particles. This concept is essential for converting between the mass of a substance and the number of particles it contains, allowing chemists to relate macroscopic measurements to microscopic quantities.
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Mole Concept
Mass Percent Composition
Mass percent composition refers to the percentage by mass of each element in a compound. It is calculated by dividing the mass of the element in the sample by the total mass of the sample and multiplying by 100. Understanding mass percent is crucial for determining the proportions of different elements in a mixture, which aids in identifying unknown substances.
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Atomic Mass and Element Identification
Each element has a unique atomic mass, which is the weighted average mass of its isotopes. By knowing the total mass of a sample and the mass percent of its constituents, one can deduce the identity of unknown elements. In this case, the atomic mass of argon and the other element can be used to identify the second constituent based on the given mass and particle distribution.
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