Chemistry · Mole concept, molar mass, percentage composition, empirical and molecular formulae

In an experiment, 4 g of oxide was reduced to of the metal. If the atomic mass o

In an experiment, 4 g of \( M_{2} O_{x} \) oxide was reduced to \( 2.8 g \) of the metal. If the atomic mass of the metal is \( 56 g m o l^{-1} \) The number of \( O- \) atoms in the oxide is:

  • A. 1
  • B. \( \frac{48}{16} \)
  • C. \( \frac{58}{32} \)
  • D. 4

Step-by-step solution

Mass of oxygen = 4 g - 2.8 g = 1.2 g. Moles of metal = 2.8/56 = 0.05 mol, so moles of oxide = 0.05/2 = 0.025 mol. Molar mass of oxide = 4/0.025 = 160 g/mol, giving 112 + 16x = 160 → x = 48/16 = 3. The number of oxygen atoms is 3, which matches option B (48/16).
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