Balance: CH4 + ?O2 - CO2 + 2H2O. What number replaces “?”

  1. 1
  2. 2
  3. 3
  4. 4
Answer

B) 2

Right side has 2 + 2 = 4 oxygen atoms, so we need 2O2: CH4 + 2O2 - CO2 + 2H2O.

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