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🧪 Chemistry  ·  Some Basic Concepts of Chemistry  ·  NEET & JEE

How many moles are present in 11.2 L of a gas at STP?

Answer: 0.5 mol.

  • A 0.25 mol
  • B 0.5 mol
  • C 1 mol
  • D 2 mol

Correct answer: B. 0.5 mol

Explanation: At STP, 1 mole of gas occupies 22.4 L. So 11.2 L = 11.2/22.4 = 0.5 mol.

Mass (g)given substanceMoles (n)amount of substanceParticlesatoms / moleculesGas Volumeat STP (litres)divide byMolar Massmultiply by6.022 x 10^23multiply by22.4 L/mol

Mass connects to moles via molar mass, and moles connect to particle count via Avogadro's number or to gas volume via the 22.4 L/mol rule at STP.

Concept context

The mole is chemistry's counting unit. Learn to relate mass, volume, and number of particles using Avogadro's number and molar mass, the foundation of all stoichiometry and reaction calculations.

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