Textbook Question
Hydrobromic acid dissolves solid iron according to the reaction:
Fe(s) + 2 HBr(aq) → FeBr2(aq) + H2(g)
What mass of HBr (in g) do you need to dissolve a 3.2-g pure iron bar on a padlock?
Ch.4 - Chemical Reactions and Chemical Quantities
Chapter 4, Problem 35
Find the limiting reactant for each initial amount of reactants.
2 Na(s) + Br2(g) → 2 NaBr(s)
a. 2 mol Na, 2 mol Br2
b. 1.8 mol Na, 1.4 Br2
c. 2.5 mol Na, 1 mol Br2
d. 12.6 mol Na, 6.9 mol Br2
Verified step by step guidance1
Identify the balanced chemical equation: \(2 \text{Na}(s) + \text{Br}_2(g) \rightarrow 2 \text{NaBr}(s)\).
Determine the mole ratio from the balanced equation: 2 moles of Na react with 1 mole of \(\text{Br}_2\).
Calculate the moles of Na required to completely react with 1 mole of \(\text{Br}_2\): \(2 \text{ moles of Na} \times \frac{1 \text{ mole of } \text{Br}_2}{2 \text{ moles of Na}} = 1 \text{ mole of } \text{Br}_2\).
Compare the available moles of Na (2.5 moles) with the moles required (2 moles) to react with 1 mole of \(\text{Br}_2\).
Determine the limiting reactant by identifying which reactant is completely consumed first based on the stoichiometric calculations.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Limiting Reactant
The limiting reactant is the substance that is completely consumed first in a chemical reaction, thus determining the maximum amount of product that can be formed. It is essential to identify the limiting reactant to calculate the theoretical yield of the reaction and understand how much of the other reactants will remain unreacted.
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Limiting Reagent Concept
Stoichiometry
Stoichiometry is the quantitative relationship between reactants and products in a chemical reaction, based on the balanced chemical equation. It allows us to determine how much of each reactant is needed or how much product can be formed from given amounts of reactants, using mole ratios derived from the coefficients in the balanced equation.
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Mole Concept
The mole concept is a fundamental principle in chemistry that relates the mass of a substance to the number of particles it contains. One mole of any substance contains Avogadro's number (approximately 6.022 x 10²³) of entities, whether they are atoms, molecules, or ions. This concept is crucial for converting between grams and moles to perform stoichiometric calculations.
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Related Practice
Textbook Question
For each of the reactions, calculate the mass (in grams) of the product that forms when 15.39 g of the underlined reactant completely reacts. Assume that there is more than enough of the other reactant.
a. 2 K(s) + Cl2(g) → 2 KCl(s)
b. 2 K(s) + Br2(l) → 2 KBr(s)
c. 4 Cr(s) + 3 O2(g) → 2 Cr2O3(s)
d. 2 Sr(s) + O2(g) → 2 SrO(s)
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Textbook Question
Find the limiting reactant for each initial amount of reactants. 4 Al(s) + 3 O2( g) → 2 Al2O3(s)
a. 1 mol Al, 1 mol O2
b. 4 mol Al, 2.6 mol O2
c. 16 mol Al, 13 mol O2
d. 7.4 mol Al, 6.5 mol O2
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Textbook Question
Consider the reaction: 4 HCl(g) + O2(g) → 2 H2O(g) + 2 Cl2(g) Each molecular diagram represents an initial mixture of reactants. How many molecules of Cl2 form from the reaction mixture that produces the greatest amount of products?
Textbook Question
Consider the reaction: 2 CH3OH(g) + 3 O2(g) → 2 CO2(g) + 4 H2O(g) Each of the molecular diagrams represents an initial mixture of the reactants. How many CO2 molecules form from the reaction mixture that produces the greatest amount of products?