Problem 55b2
(b) Menthol, the substance we can smell in mentholated cough drops, is composed of C, H, and O. A 0.1005-g sample of menthol is combusted, producing 0.2829 g of CO2 and 0.1159 g of H2O. What is the empirical formula for menthol? If menthol has a molar mass of 156 g/mol, what is its molecular formula?
Problem 7d2
Nitrogen 1N22 and hydrogen 1H22 react to form ammonia 1NH32. Consider the mixture of N2 and H2 shown in the accompanying diagram. The blue spheres represent N, and the white ones represent H. (d) If so, how many of which type are left over?
How many N2 molecules are left over?
Problem 105c3
When a mixture of 10.0 g of acetylene 1C2H22 and 10.0 g of oxygen 1O22 is ignited, the resulting combustion reaction produces CO2 and H2O. (c) How many grams of CO2 are present after the reaction is complete?
Problem 105c1
When a mixture of 10.0 g of acetylene 1C2H22 and 10.0 g of oxygen 1O22 is ignited, the resulting combustion reaction produces CO2 and H2O. (c) How many grams of C2H2 are present after the reaction is complete?
Problem 7d1
Nitrogen 1N22 and hydrogen 1H22 react to form ammonia 1NH32. Consider the mixture of N2 and H2 shown in the accompanying diagram. The blue spheres represent N, and the white ones represent H. (d) Are any reactant molecules left over, based on the diagram?
Problem 1
The reaction between reactant A (blue spheres) and reactant B (red spheres) is shown in the following diagram:
Based on this diagram, which equation best describes the reaction? (a) A2 + B¡A2B (b) A2 + 4 B¡2 AB2 (c) 2 A + B4¡2 AB2 (d) A + B2¡AB2
Problem 2a
The following diagram shows the combination reaction between hydrogen, H2, and carbon monoxide, CO, to produce methanol, CH3OH (white spheres are H, black spheres are C, red spheres are O). The correct number of CO molecules involved in this reaction is not shown. (a) Determine the number of CO molecules that should be shown in the left (reactants) box.
Problem 2b
The following diagram shows the combination reaction between hydrogen, H2, and carbon monoxide, CO, to produce methanol, CH3OH (white spheres are H, black spheres are C, red spheres are O). The correct number of CO molecules involved in this reaction is not shown. (b) Write a balanced chemical equation for the reaction.
Problem 3a
The following diagram represents the collection of elements formed by a decomposition reaction. (a) If the blue spheres represent N atoms and the red ones represent O atoms, what was the empirical formula of the original compound?
Problem 3b
The following diagram represents the collection of elements formed by a decomposition reaction. (b) Could you draw a diagram representing the molecules of the compound that had been decomposed? Why or why not?
Problem 4
The following diagram represents the collection of CO2 and H2O molecules formed by complete combustion of a hydrocarbon. What is the empirical formula of the hydrocarbon?
Problem 5a
Glycine, an amino acid used by organisms to make proteins, is represented by the following molecular model. (a) Write its molecular formula.
Problem 5c
Glycine, an amino acid used by organisms to make proteins, is represented by the following molecular model. (c) Calculate how many moles of glycine are in a 100.0-g sample of glycine.
Problem 5d
Glycine, an amino acid used by organisms to make proteins, is represented by the following molecular model. (d) Calculate the percent nitrogen by mass in glycine.
Problem 6a
The following diagram represents a high-temperature reaction between CH4 and H2O. Based on this reaction, find how many moles of each product can be obtained starting with 4.0 mol CH4.
Based on this reaction, find how many moles of CO can be obtained starting with 4.0 mol CH4?
Problem 6b
The following diagram represents a high-temperature reaction between CH4 and H2O. Based on this reaction, find how many moles of each product can be obtained starting with 4.0 mol CH4. Based on this reaction, how many moles of H2 can be obtained starting with 4.0 mol CH4?
Problem 7a
Nitrogen 1N22 and hydrogen 1H22 react to form ammonia 1NH32. Consider the mixture of N2 and H2 shown in the accompanying diagram. The blue spheres represent N, and the white ones represent H. (a) Write the balanced chemical equation for the reaction.
Problem 8a
Nitrogen monoxide and oxygen react to form nitrogen dioxide. Consider the mixture of NO and O2 shown in the accompanying diagram. The blue spheres represent N, and the red ones represent O. (a) How many molecules of NO2 can be formed, assuming the reaction goes to completion?
Problem 8c
Nitrogen monoxide and oxygen react to form nitrogen dioxide. Consider the mixture of NO and O2 shown in the accompanying diagram. The blue spheres represent N, and the red ones represent O. (c) If the actual yield of the reaction was 75% instead of 100%, how many molecules of each kind would be present after the reaction was over?
Problem 9a
Write 'true' or 'false' for each statement. (a) We balance chemical equations as we do because energy must be conserved.
Problem 9b
Write 'true' or 'false' for each statement. (b) If the reaction 2 O3(g)S 3 O2(g) goes to completion and all O3 is converted to O2, then the mass of O3 at the beginning of the reaction must be the same as the mass of O2 at the end of the reaction.
Problem 10
A key step in balancing chemical equations is correctly identifying the formulas of the reactants and products. For example, consider the reaction between calcium oxide, CaO(s), and H2O1l2 to form aqueous calcium hydroxide. (b) Is it possible to balance the equation if you incorrectly identify the product as CaOH1aq2, and if so, what is the equation?
Problem 11c
Balance the following equations: (c) Al(OH)31s2 + H2SO41l2¡Al2(SO4)3(s) + H2O(l)
Problem 12b
Balance the following equations: (b) Au2S31s2 + H21g2¡Au1s2 + H2S1g2
Problem 12c
Balance the following equations: (c) Ba3N21s2 + H2O1aq2¡Ba(OH)21aq2 + NH31g2
Problem 12d
Balance the following equations: (d) Na2CO31aq2 + HCl1aq2¡NaCl1aq2 + H2O1l2 + CO2(g)
Problem 13b
Balance the following equations: (b) NH31g2 + O21g2¡NO1g2 + H2O1g2
Problem 14b
Balance the following equations: (b) Cu1s2 + HNO31aq2¡Cu(NO3)21aq2 + NO21g) + H2O(l)
Problem 14c
Balance the following equations: (c) MnO21s2 + HCl1aq2 ¡MnCl21s2 + H2O1l2 + Cl2(g)
Problem 14d
Balance the following equations: (d) KOH1aq2 + H3PO41aq2 ¡K3PO41aq2 + H2O1l2
Ch.3 - Chemical Reactions and Reaction Stoichiometry
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