Chapter 9, Problem 5A

Interpretation Introduction

Interpretation:

The mass of water needed to completely react with 20.0 g of PCl₃ needs to be deduced based on the given reaction.

Concept Introduction:

• A chemical reaction is expressed as a chemical equation having reactants and products on left and right side of the reaction arrow respectively.

  $\text{Reactants }\to \text{ Products}$

• The coefficient of a balanced chemical equation i.e. the stoichiometry gives the amount of reactants and products involved in the reaction.
• The stoichiometric ratio between the reactants or between reactants and products is expressed in terms of the mole-mole ratio

Answer to Problem 5A

False.

Explanation of Solution

The given reaction is:

  $2{\text{H}}_{\text{2}}{\text{O}}_2\text{(aq) }\to 2{\text{H}}_2{\text{O(l) + O}}_{\text{2}}\text{(g) }$

The statement that 2 g of H₂O₂ decomposes to form 2 g of H₂O and 1 g of O₂ is false since the stoichiometric coefficients associated with the reactant and products represent the moles of substances. Therefore, the correct statement would be: 2 moles of H₂O₂decomposes to form 2 moles of H₂O and 1 mole of O₂.

Conclusion

Therefore, a balanced chemical equation is interpreted based on the mole-mole ratios of the reactants and products.