Ch.4 - Chemical Quantities & Aqueous Reactions

Problem 33

Chapter 4, Problem 33

For each of the reactions, calculate the mass (in grams) of the product that forms when 3.67 g of the underlined reactant completely reacts. Assume that there is more than enough of the other reactant. a. Ba(s) + Cl2(g) → BaCl2(s) b. CaO(s) + CO2(g) → CaCO3(s) c. 2 Mg(s) + O2(g) → 2 MgO(s) d. 4 Al(s) + 3 O2(g) → 2 Al2O3(s)

Verified step by step guidance

Identify the underlined reactant in each reaction and note its molar mass.

Convert the mass of the underlined reactant (3.67 g) to moles using its molar mass: \( \text{moles} = \frac{\text{mass}}{\text{molar mass}} \).

Use the stoichiometry of the balanced chemical equation to determine the moles of product formed from the moles of the underlined reactant.

Calculate the molar mass of the product in each reaction.

Convert the moles of product to grams using its molar mass: \( \text{mass} = \text{moles} \times \text{molar mass} \).

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 the reactants and products in a chemical reaction. It allows chemists to predict the amounts of substances consumed and produced in a reaction based on balanced chemical equations. Understanding stoichiometry is essential for calculating the mass of products formed from a given mass of reactants.

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all the atoms in a molecule. Knowing the molar mass of reactants and products is crucial for converting between grams and moles, which is necessary for stoichiometric calculations in chemical reactions.

Balanced Chemical Equations

A balanced chemical equation represents a chemical reaction with equal numbers of each type of atom on both sides of the equation. Balancing ensures the law of conservation of mass is upheld, meaning that matter is neither created nor destroyed in a reaction. This is fundamental for stoichiometric calculations, as it provides the ratios needed to determine the amounts of reactants and products involved.

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Related Practice

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? What mass of H₂ would the complete reaction of the iron bar produce?

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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?

3885

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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 15.2 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?

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

For each of the acid–base reactions, calculate the mass (in grams) of each acid necessary to completely react with and neutralize 4.85 g of the base. b. 2 HNO₃(aq) + Ca(OH)₂(aq) → 2 H₂O(l) + Ca(NO₃)₂(aq)

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Open Question

For each precipitation reaction, calculate how many grams of the first reactant are necessary to completely react with 55.8 g of the second reactant. a. 2 KI(aq) + Pb(NO3)2(aq) → PbI2(s) + 2 KNO3(aq) b. Na2CO3(aq) + CuCl2(aq) → CuCO3(s) + 2 NaCl(aq) c. K2SO4(aq) + Sr(NO3)2(aq) → SrSO4(s) + 2 KNO3(aq)