Dinitrogen tetraoxide is a colorless gas at room temperature. It can dissociate into nitrogen dioxide, which is a reddish brown gas. N204(g)= 2 NO2(g) Three experiments were run starting with different initial amounts of N2O4(g) ([N2O40 in the table). The systems were allowed to reach equilibrium and the concentrations for each gas were measured (in units of moles/Liter). For each of the boxes below, calculate the ratios indicated by the column heading. This will show the mathematical relationship that exists between the concentrations of NO2 and N2O4 at equilibrium. Be sure to round to the correct number of significant figures. Exp [N204]0 [NO2] [N204] [NO2] / [N204] 2 [NO2] / [N204] [NO2]²/ [N204] 1 3.7 2.92 2.2 2 2.8 2.49 1.6 3 2.4 2.24 1.3 Based on your calculations, indicate whether each statement is True (T) or False (F): 1. Each experiment started with a different initial concentration of N2O4- 2. The ratio ([NO2]/[N204]) is equal to a constant value. 3. The ratio (2 [NO2]/[N2O4]) is equal to a constant value. 4. The ratio ([NO2]/[N204]) is equal to a constant value. 5. Each experiment reached a different set of equilibrium concentrations.

Write balanced net ionic equations for the following reactions in acid solution. (a) Liquid hydrazine reacts with an aqueous solution of sodium bromate. Nitrogen gas and bromide ions are formed. (b) Solid phosphorus (P4) reacts with an aqueous solution of nitrate to form nitrogen oxide gas and dihydrogen phosphate (H2PO4-) ions. (c) Aqueous solutions of potassium sulfite and potassium permanganate react. Sulfate and manganese(II) ions are formed.

Describe in words how you would prepare pure crystalline AgCl and NaNO3 from solid AgNO3 and solid NaCl.

Solubility and Solubility Product You put 0.10-mol samples of KNO3, (NH4)2S, K2S, MnS, AgCl, and BaSO4 into separate flasks and add 1.0 L of water to each one. Then you stir the solutions for 5 minutes at room temperature. Assume that you have 1.0 L of solution in each case. a Are there any beakers where you would observe solid still present? How do you know? b Can you calculate the potassium ion concentration, K+, for the solutions of KNO3 and K2S? If so, do the calculations, and then compare these K+ concentrations. c For the solutions of (NH4)2S, K2S, and MnS, how do the concentrations of sulfide ion, S2, compare? (You dont need to calculate an answer at this point; just provide a rough comparison.) Be sure to justify your answer. d Are there any cases where you need more information to calculate the sulfide-ion concentration for the solutions of (NH4)2S, K2S, and MnS from part c? If so, what additional information do you need? e Consider all of the solutions listed at the beginning of this problem. For which ones do you need more information than is given in the question to determine the concentrations of the ions present? Where can you find this information? f How is the solubility of an ionic compound related to the concentrations of the ions of the dissolved compound in solution?

Given HFH+(aq)+F(aq)Ka=6.9104HF(aq)+F(aq)H2(aq)K=2.7 calculate K for the reaction 2HF(aq)H+(aq)+HF2(aq)

What is the oxidation number of S in each of the following molecules? a. S2 b. S8 c. H2S d. SO3

A chemist dissolves a 1.497-g sample of a type of metal (an alloy of Sn, Pb, Sb, and Cu) in nitric acid, and metastannic acid, H2SnO3, is precipitated. She heats the precipitate to drive off the water, which leaves 0.4909 g of tin(IV) oxide. What was the percentage of [in in the original sample?

68. Aluminum ion may be precipitated from aqueous solution by addition of hydroxide ion, forming Al(OH)3. A large excess of hydroxide ion must not be added, however, because the precipitate of Al(OH)3 will redissolve as a soluble compound containing aluminum ions and hydroxide ions begins to form. How many grains of solid NaOH should be added to 10.0 mL of 0.250 M A1Cl3 to just precipitate all the aluminum?

A mountain lake that is 4.0 km × 6.0 km with an average depth of 75 m has an H+(aq) concentration of 1.3 × 10−6 M. Calculate the mass of calcium carbonate that would have to be added to the lake to change the H+(aq) concentration to 6.3 × 10−8 M. Assume that all the carbonate is converted to carbon dioxide, which bubbles out of the solution.

Use the appropriate tables to calculate H for (a) the reaction between MgC03(s) and a strong acid to give Mg2+(aq), CO2(g), and water. (b) the precipitation of iron(III) hydroxide from the reaction between iron(III) and hydroxide ions.