Question

The value of 1 amu is equal to: (a) \(1.66 \times 10^{-24} \mathrm{~g}\) (b) \(12.00 \times 10^{-24} \mathrm{~g}\) (c) \(1.992 \times 10^{-24} \mathrm{~g}\) (d) \(1.0 \mathrm{~g}\)

Short answer

The value of 1 amu is (a) 1.66 × 10^{-24} grams.

Step-by-step solution

Understand Atomic Mass Unit (amu)

An atomic mass unit (amu) is a standard unit of mass that quantifies mass on an atomic or molecular scale. It is defined as one-twelfth the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state.

Look for the Correct amu Value

The commonly accepted equivalent mass of 1 amu in grams is approximately 1.66 × 10^{-24} grams.

Match the Correct Value

From the choices given: (a) 1.66 × 10^{-24} grams, (b) 12.00 × 10^{-24} grams, (c) 1.992 × 10^{-24} grams, (d) 1.0 grams, option (a) 1.66 × 10^{-24} grams matches the known value for 1 amu.

Key concepts

carbon-12 isotope

The carbon-12 isotope is pivotal in the world of chemistry because it serves as the standard for defining atomic mass units (amu). This isotope of carbon contains six protons and six neutrons, making a total of 12 nucleons. As a result, by definition, one atomic mass unit is exactly one-twelfth of the mass of a carbon-12 atom. The significance of carbon-12 lies in its stable and abundant nature, ensuring consistency and accuracy in atomic mass measurements. Therefore, any calculation involving atomic masses relies fundamentally on the properties of carbon-12.

mass on atomic scale

When talking about mass on an atomic scale, we are concerned with extremely small units of measurement. Atoms and molecules are so tiny that comparing their masses requires a specific unit, which is where the atomic mass unit (amu) comes into play. On this scale, the amu allows us to express these minuscule masses in a way that is understandable and practical, such as representing the mass of a single atom or molecule.

• The mass of protons, neutrons, and electrons is measured in amu.
• One amu is roughly equivalent to the mass of a proton or neutron.

By using amu, scientists can easily perform calculations and convey information about atomic and molecular masses in a standardized form.

conversion of amu to grams

Converting an atomic mass unit to grams bridges the tiny world of atoms with the more familiar metric system. Since 1 amu is defined relative to the carbon-12 isotope, we know that its conversion into grams involves precise calculations. The widely accepted conversion factor is:\[ 1 \text{ amu} = 1.66 \times 10^{-24} \text{ grams} \]This conversion option helps chemists and physicists express the mass of atoms in macroscale contexts, allowing equations and reactions to be understood and measured in everyday terms. This understanding is crucial for lab work, where the theoretical calculations must align with real-world measurements to ensure accuracy and application.