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Calculate the number of grams of H2O formed when 8g of CH4 burns in excess of oxygen.

Correct answer: C. 18 grams

  • A. 21 grams
  • B. 19 grams
  • C. 18 grams
  • D. 15 grams

Explanation

Mass of CH4 = 8g Molar mass CH4 = 16g/mol Moles = 8g/16g/mol = 0.5mol CH4 + 2O2 → CO2+ 2H2O Compare the mole ratios. The mole ratio of CH4 to H2O is 1 :2 0.5 mole of CH4= 2 x 0.5mol = 1 mol of H2O Moles of H2O is 1mol Molar mass of H2O = 18g/mol Mass of H2O = moles X molar mass = 1 mol x 18g/mol = 18g Mass of water produced is 18g.

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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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