Concept explainers
For each of the following unbalanced reactions, suppose exactly 5.00 g of each reactant is taken. Determine which reactant is limiting, and also determine what mass of the excess reagent will remain after the limiting reactant is consumed.
- Na2B4O7(s) + H2SO4(o H 3BOj(j) + Na 2SO 4(u
- CaC,(s) + H2O(/) → Ca(OH)2(s) + C2H2(g)
- NaCl(s) + H2SO4(/> → HCl(g) + Na2SO4(s)
- SiO2(s) + C(x) —> Si(/) + CO(g)
(a)
Interpretation : For the given reaction with 5 g of each reactant, the limiting reactant and the mass of the excess reactant after the completion of limiting reactant needs to be determined.
Concept Introduction : Stoichiometry is used in order to relate molar and mass quantities. The limiting reactant will always finish first than the excess materials.
Answer to Problem 45QAP
Explanation of Solution
Given
In order to make stoichiometric calculations, the reaction must be balanced:
Balance B:
Balance H
This is now balanced.
Calculate moles of reactants
Where MM is molar mass
Perform stoichiometric calculations:
From these calculations, the limiting reactant is
Excess moles:
Mass left:
(b)
Interpretation : For the given reaction with 5 g of each reactant, the limiting reactant and the mass of the excess reactant after the completion of limiting reactant needs to be determined.
Concept Introduction : Stoichiometry is used in order to relate molar and mass quantities. The limiting reactant will always finish first than the excess materials.
Answer to Problem 45QAP
Explanation of Solution
Given
In order to make stoichiometric calculations, the reaction must be balanced:
Balance O:
This is now balanced.
Calculate moles of reactants
Perform stoichiometric calculations:
From these calculations, the limiting reactant is
Excess moles:
Mass left:
(c)
Interpretation : For the given reaction with 5 g of each reactant, the limiting reactant and the mass of the excess reactant after the completion of limiting reactant needs to be determined.
Concept Introduction : Stoichiometry is used in order to relate molar and mass quantities. The limiting reactant will always finish first than the excess materials.
Answer to Problem 45QAP
Explanation of Solution
Given
In order to make stoichiometric calculations, the reaction must be balanced:
Balance Na:
Balance H:
This is now balanced.
Calculate moles of reactants
Perform stoichiometric calculations:
From these calculations, the limiting reactant is
Excess moles:
Mass left:
(d)
Interpretation : For the given reaction with 5 g of each reactant, the limiting reactant and the mass of the excess reactant after the completion of limiting reactant needs to be determined.
Concept Introduction : Stoichiometry is used in order to relate molar and mass quantities. The limiting reactant will always finish first than the excess materials.
Answer to Problem 45QAP
Explanation of Solution
Given
In order to make stoichiometric calculations, the reaction must be balanced:
Balance O:
Balance C:
This is now balanced.
Calculate moles of reactants
Perform stoichiometric calculations:
From these calculations, the limiting reactant is
Excess moles:
Mass left:
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Chapter 9 Solutions
Introductory Chemistry: A Foundation
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