Moderate

Which of the following contains 1 mole of particles?

Correct answer: C. Electrons in 1 g of hydrogen gas

  • A. Chlorine molecules in 35.5 g of chlorine gas
  • B. Hydrogen ions in 1 dm3 of 1 mol dm-3 aqueous sulphuric acid
  • C. Electrons in 1 g of hydrogen gas
  • D. Oxygen atoms in 22.4 dm3 of oxygen gas at STP

Explanation

The correct answer is Option C. 1 g of hydrogen gas (H2) is approximately 0.5 moles, and each H2 molecule has 2 electrons, providing 1 mole of electrons (6.022 x 1023 electrons). Option A is incorrect as 35.5 g of chlorine is 0.5 moles, not 1. Option B is incorrect because 1 dm3 of 1 mol dm-3 H2SO4 provides 2 moles of H+ ions. Option D is incorrect because 22.4 dm3 of O2 gas at STP contains 2 moles of oxygen atoms.

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About Fundamental Concepts of Chemistry

Mole calculations connect mass, number of particles and Avogadro's number, while balanced equations provide the mole ratios used in stoichiometry. Questions cover limiting and excess reactants, theoretical yield and percentage yield, including identifying which reactant is consumed first and comparing the actual product with the maximum possible product.

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