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Ch.4 - Chemical Reactions and Chemical Quantities
Tro - Chemistry: A Molecular Approach 6th Edition
Tro6th EditionChemistry: A Molecular ApproachISBN: 9780137832217Not the one you use?Change textbook
All textbooksTro 6th EditionCh.4 - Chemical Reactions and Chemical QuantitiesProblem 40
Chapter 4, Problem 40

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)

Verified step by step guidance
1
Identify the underlined reactant, which is Sr (Strontium) in this case.
Write the balanced chemical equation: \( 2 \text{Sr} (s) + \text{O}_2 (g) \rightarrow 2 \text{SrO} (s) \).
Calculate the molar mass of the underlined reactant, Sr, using the periodic table.
Convert the mass of Sr given (15.39 g) to moles using its molar mass.
Use the stoichiometry of the balanced equation to find the moles of SrO produced, then convert this to grams using the molar mass of SrO.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between reactants and products in a chemical reaction. It allows us to calculate the amount of product formed from a given amount of reactant using the coefficients from the balanced chemical equation. In this case, understanding the stoichiometric ratios is essential to determine how much strontium oxide (SrO) can be produced from the given mass of strontium (Sr).
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Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is crucial for converting between the mass of a substance and the number of moles, which is necessary for stoichiometric calculations. For the reaction provided, calculating the molar mass of strontium and strontium oxide will enable the conversion of the mass of strontium into moles and subsequently into grams of the product formed.
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Balanced Chemical Equation

A balanced chemical equation represents a chemical reaction with equal numbers of each type of atom on both sides of the equation. It ensures the law of conservation of mass is upheld. In the reaction 2 Sr(s) + O2(g) → 2 SrO(s), the coefficients indicate that two moles of strontium react with one mole of oxygen to produce two moles of strontium oxide, which is essential for determining the amounts of reactants and products involved.
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Related Practice
Textbook Question

Find the limiting reactant for each initial amount of reactants. 4 Al(s) + 3 O2( g) → 2 Al2O3(s)

a. 4 mol Al, 2 mol O2

b. 5 mol Al, 3 mol O2

c. 17 mol Al, 11 mol O2

d. 8.8 mol Al, 7.2 mol O2

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 2.80-g pure iron bar on a padlock? What mass of H2 would the complete reaction of the iron bar produce?

Textbook Question

Sulfuric acid dissolves aluminum metal according to the reaction:

2 Al(s) + 3 H2SO4(aq) → Al2(SO4)3(aq) + 3 H2(g)

Suppose you want to dissolve an aluminum block with a mass of 11.3 g. What minimum mass of H2SO4 (in g) do you need? What mass of H2 gas (in g) does the complete reaction of the aluminum block produce?

Textbook Question

Find the limiting reactant for each initial amount of reactants. 2 Na(s) + Br2( g) → 2 NaBr(s) c. 1.5 mol Na, 2.1 mol Br2

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?