‘amu’ has been replaced by ‘u’ which is known as …A… Here, A refers to — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question

💡 Solution & Explanation

# Understanding the Replacement of 'amu' with 'u' **Step 1: Identify what 'amu' stands for** The term 'amu' historically meant "atomic mass unit." **Step 2: Recognize the modern SI replacement** The International Union of Pure and Applied Chemistry (IUPAC) replaced 'amu' with the symbol 'u' to standardize nomenclature across scientific disciplines. **Step 3: Determine what 'u' officially represents** The symbol 'u' is now the standard abbreviation for the **unified atomic mass unit** (or sometimes called the **universal atomic mass unit**). **Step 4: Understand the definition** One unified atomic mass unit (u) is defined as exactly 1/12 of the mass of a carbon-12 ($^{12}C$) atom, making it the modern standard for measuring atomic and molecular masses. --- **Answer: A = Unified Atomic Mass Unit (u)** The replacement was made to achieve international standardization and clarity in atomic mass measurements across all scientific communities.