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Ch.2 Atoms and the Periodic Table
McMurry - Fundamentals of GOB 8th Edition
McMurry8th EditionFundamentals of GOBISBN: 9780134015187Not the one you use?Change textbook
Chapter 2, Problem 85a

What is the mass (in amu and in grams) of a single atom of Carbon-12?

Verified step by step guidance
1
Understand the problem: Carbon-12 is an isotope of carbon with a mass number of 12. The mass of a single atom of Carbon-12 is defined as exactly 12 atomic mass units (amu) by definition of the atomic mass unit.
To express the mass in grams, recall the relationship between amu and grams: 1 amu = 1.660539066 × 10⁻²⁴ grams.
Multiply the mass of the Carbon-12 atom in amu (12 amu) by the conversion factor to convert it to grams: \( \text{Mass in grams} = 12 \times 1.660539066 \times 10^{-24} \).
Perform the multiplication to determine the mass of a single Carbon-12 atom in grams. This step involves basic arithmetic with scientific notation.
Summarize the results: The mass of a single Carbon-12 atom is 12 amu by definition, and the calculated value in grams will be the result of the multiplication in the previous step.

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Key Concepts

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

Atomic Mass Unit (amu)

The atomic mass unit (amu) is a standard unit of mass used to express atomic and molecular weights. It is defined as one twelfth of the mass of a carbon-12 atom, which is approximately 1.66 x 10^-27 kilograms. This unit allows for easier comparison of the masses of different atoms and molecules, as they are typically very small.
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Atomic Mass (Conceptual) Concept 1

Carbon-12 Isotope

Carbon-12 is one of the most common isotopes of carbon, consisting of 6 protons and 6 neutrons in its nucleus. It is used as a standard for atomic mass measurements and has an atomic mass of exactly 12 amu. Understanding isotopes is crucial for calculations involving atomic mass, as different isotopes of an element can have varying masses.
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Conversion between amu and grams

The conversion between atomic mass units (amu) and grams is essential for expressing atomic masses in a more practical unit. One amu is equivalent to 1.66053906660 x 10^-24 grams. This relationship allows scientists to convert the mass of an atom from amu to grams, facilitating calculations in chemistry and physics.
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Conversion Factors (Simplified) Example 2