When the following reaction equation is properly balanced, the number of moles of O2 will beC3H8 +O2 ⇌ CO2 +H2O

Correct answer: B. 3

  • A. 1.5
  • B. 3
  • C. 3.5
  • D. 5

Explanation

The balancing process involves adjusting the stoichiometric coefficients (numbers in front of each chemical formula) to ensure that the number of atoms of each element is the same on both sides of the reaction arrow. Here's how we achieve that:Start with Carbon (C): We have 3 C atoms on the left and 3 C atoms on the right, so they are already balanced.Balance Hydrogen (H): We have 8 H atoms on the left and 8 H atoms on the right, so they are balanced as well.Balance Oxygen (O): On the left, we have 2 O atoms from H2O. To balance the 8 O atoms in 5O2 on the right, we simply need 4 H2O molecules, resulting in 8 O atoms on both sides.With this balanced equation, you can see that 5 moles of O2 are required to react with 1 mole of C3H8, meaning 1.5 moles of O2 are needed for 0.3 moles of C3H8, which confirms option (b) as the correct answer.

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About Reaction Kinetics

Reaction kinetics relates reaction rate to concentration, temperature, surface area and catalysts. Questions cover rate laws, reaction order, rate constants, activation energy and the activated complex, including how a catalyst lowers the activation energy without changing the overall energy change or equilibrium position.

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