Equilibrium Questions and Answers

Choose the balanced equation for the reaction, even if the reaction is reactant-favored. NH₄⁺(aq) + HSO₄‾(aq) A. NH₄⁺(aq) + HSO₄‾(aq) –> NH(aq) + H₂SO₄(aq) B. NH₄⁺(aq) + HSO₄‾(aq) -> NH₅²⁺(aq) + SO₄²‾(aq) C. NH₄⁺(aq) + HSO₄‾(aq) -> NH₄HSO₄(s) D. NH₄⁺(aq) + HSO₄‾(aq) -> N₂(g) + 2SO₂(g) + 5H₂O(l)

Choose the chemical equation for the autoionization of water. a. 2H₂O(l) ⇄ 2H₂(g) + O₂(g) b. 2H₂O(l) ⇄ OH⁺(aq) + H₂O‾(aq) c. 3H₂O(l) ⇄ O₂‾(aq) + 2H₂O⁺(aq) d. 2H₂O(l) ⇄ OH‾(aq) + H₂O⁺(aq)

The ionization constant of a very weak acid, HA, is 5.2x10‾⁹. Calculate the equilibrium concentrations of H₃O⁺, A‾, and HA in a 0.040 M solution of the acid. Determine the concentrations of all species at equilibrium and the solution pH. [H₃O⁺] = mol/L [A‾] = mol/L [HA] = mol/L pH =

What is the pH of a 3.17x10‾⁵ M solution of the strong acid HClO₄? HClO₄(aq) + H₂O(l) –> ClO₄‾(aq) + H₃O⁺(aq) [HCIO₄]₀ = 3.17 x 10‾⁵

Problem Statement: Estimate how many Rolaids tablets are required to neutralize all the acid in one glass (250 mL) of a regular cola drink. Assume that: cola drink pH = 3.0 one Rolaids tablet contains 334 mg of NaAl(OH)₂CO₃ To make this estimate, assume that the pH indicates the total concentration of acid in the cola. Then, figure out how many moles of H⁺(aq) are present in the acidic cola drink and how many moles of H⁺(aq) each tablet can consume. Let's start with the first part. First Step in Solution: Calculate the [H⁺(aq)] in a pH = 3.0 solution.

A mixture of reactants and products for the reaction shown below is at equilibrium in a 1.0 L container. What would happen to the equilibrium if argon gas were added to the container? N₂(g) + 3H₂(g) = 2NH3(g) A. Less N₂, H2, and NH3 would be produced until equilibrium was reached. B. More NH3 would be produced until equilibrium was reached. C. More N₂ and H₂ would be produced until equilibrium was reached. D. The concentrations of N₂, H₂, and NH3 would remain the same.

A student placed a small piece of magnesium ribbon in a conical flask and added 60 mL hydrochloric acid. The student observed that when the hydrochloric acid came into contact with the magnesium ribbon, bubbles formed indicating the release of hydrogen gas. The magnesium dissolved and magnesium chloride solution formed. Based on the student's observations, which type of reaction occurred? Mg + 2HCI → MgCl₂ + H₂ A. combustion reaction B. decomposition reaction C. single replacement reaction D. double replacement reaction

Hydrogen gas reacts with oxygen gas to produce water, as shown below: 2H2 + O2 2H₂O Approximately how many grams of hydrogen gas are needed to completely react with 128 grams of oxygen gas? 31.68 g H₂ 8.08 g H2 16.16g H2 30.68 g H₂

Chlorine and hydrogen gas react to form hydrogen chloride as shown in the following reaction: Cl2 (g) + H₂ (g) → 2HCI (g) If a 48.5 L sample of chlorine gas was reacted with excess hydrogen at 450 K and 1.20 atm, how many grams of hydrogen chloride is produced?

Two clear solutions are placed in separate beakers. The first solution has a pH of 4, and the second solution is unknown. The two solutions are mixed together and the resulting pH is 5. Which of the following statements must be true about the second solution? A. It is more acidic. B. It is neutral. C. It contains more hydroxide ion than the first solution. D. It contains more hydrogen ion than the first solution.

B. Calculate K, for the weak acid described above. HA (aq) + H₂O (1) H₂O+ (aq) + A (aq)

When an acid and base are mixed together in a neutralization reaction, the products of the reaction are always: a) a stronger acid and base b) salt and water c) salt and carbon dioxide d) carbon dioxide and water

Silver chromate is sparingly soluble in aqueous solutions. The Ksp of Ag₂ CrO4 is 1.12 x 10-¹². What is the solubility (in mol/L) of silver chromate in 1.00 M potassium chromate aqueous solution? solubility: What is the solubility (in mol/L) of silver chromate in 1.00 M silver nitrate aqueous solution? solubility: What is the solubility (in mol/L) of silver chromate in pure water? solubility:

You need to prepare 100.0 mL of a pH 4.00 buffer solution using 0.100 M benzoic acid (pK₂ = 4.20) and 0.120 M sodium benzoate. How many milliliters of each solution should be mixed to prepare this buffer?

Which of the following must be true if a chemical reaction is at equilibrium? A. The chemical reaction is reversible. B. All of the reactants are soluble in water. C. The chemical reaction is exothermic. D. The products have more energy than the reactants.

Given that Kw for water is 2.4 x 10-14 at 37 °C, calculate the pH of a neutral aqueous solution at 37 °C, which is the normal human body temperature. Is a pH = 7.00 solution acidic, basic, or neutral at 37 °C?

Which of the following statements is true concerning acids and bases? Acids and bases don't react with each other. Acids mixed with bases make stronger acids. Acids mixed with bases neutralize each other. Acids mixed with bases make stronger bases.

The difference between a strong acid like HBr and a weak acid like HF is that: A. HBr will always have a lower pH than HF, no matter the concentration. B. HBr is dangerous and HF is only slightly corrosive C. HBr will ionize completely in water while HF will not D. HBr always has a pH lower than 7 and HF will not

What is the pH of a 325.0 mL solution that contains 3.52x10-4 mol of HCIO4?

At what temperature will 15 g of NH4Cl dissolve in 50 g of H₂O?

For the following reaction between chlorous acid and strontium hydroxide, write the chemical reaction, predict the products, and balance. In the boxes below the reaction, identify the acid. base, and salt (you should leave one of the boxes blank). Fill in the boxes in the order of the word problem and make sure to put a coefficient for all compounds. Make sure Water is LAST!

Acids are very good at removing hard water deposits from bathtubs, sinks, and glassware. Your father goes to the store to buy a cleaner to remove such deposits from your bathtub. He has a choice between a product containing lemon juice (H¹ = 10-2.5 M) and one containing vinegar (H+ = 10-3.3 M). Which product would you recommend he purchase? Explain your answer.

Which equation depicts aqueous hydrogen sulfide behaving as a Brønsted-Lowry base in water? A) H₂S(aq) + H3O*(aq) → H3S*(aq) + H₂O(l) B H₂S(aq) + 2 OH- (aq) → SO₂(aq) + 2 H₂(g) C HS (aq) + H₂O¹(aq) → H₂S(aq) + H₂O(l) D H₂S(aq) + H₂O(l) → HS (aq) + H₂O*(aq)

An ionic compound has a solubility of 30 grams per 100 mL of water at room temperature. A solution of the same substance that contains 80 grams of the compound in 250 mL of water at room temperature is: saturated unsaturated supersaturated immiscible

What is the equilibrium constant for the following reaction, HCO₂H(aq) + CN- (aq) HCO₂ (aq) + HCN(aq) and does the reaction favor the formation of reactants or products? The acid dissociation constant, K₂, for HCO₂H is 1.8 x 104 and the acid dissociation constant for HCN is 4.0 x 10-10. A K= 2.2 x 10-6. The reaction favors the formation of products. B K= 4.5 x 105. The reaction favors the formation of products. C K= 4.5 x 10³. The reaction favors the formation of reactants. D K= 2.2 x 10-6. The reaction favors the formation of reactants.

0.149 mol/L of A₂(g) and 0.149 B₂(g) are initially present in a flask. The A₂ and B2 react according to the balanced equation below. A₂(g) + B₂(g) = 2 AB(g) When equilibrium is reached, the concentration of B₂(g) has decreased to 0.036 mol/L. What is the equilibrium constant, Kc, for the reaction?

What volume of water do you dissolve 50.0g of NaOH in to make a 0.750M solution? a. 1.67 L b.0.560 L c. 1500 L d. 0.938 L

Consider the Ka values for the following acids: Cyanic acid, HOCN, 3.5 x 10-4 Formic acid, HCHO₂, 1.7 x 10-4 Lactic acid, HC3H5O3, 1.3 x 10-4 Propionic acid, HC3H5O2, 1.3 x 10-5 Benzoic acid, HC₂H5O₂, 6.3 x 10-5 Which has the weakest conjugate base? A HC3H₂O2 B HCHO₂ CHC3H503 D HOCN

Which solution below has the highest concentration of hydronium ions? a.pH = 4.21 b. pH = 11.6 c. pH = 6.93 d. pH = 8.82

Which of the following combinations would be best to buffer an aqueous solution at a pH of 4.94? A HNO₂ and NO₂, K₂ = 4.5 x 10-4 B H₂PO4 and H₂PO4, Ka1 = 7.5 x 10-³ C H₂PO4 and HPO42-, Ka2 = 6.2 x 10-8 D CH3CO₂H and CH3COO-, K₂ = 1.8 × 10-5

A buffer solution contains dissolved C6H5NH₂ and C6H5NH3Cl. The initial concentration of C6H5NH₂ is 0.50 M and the pH of the buffer is 4.20. Determine the concentration of C6H5NH3* in the solution. The value of Kb for C6H5NH₂ is 3.8 × 10-¹⁰. Initial (M) Change (M) Equilibrium (M) Let x represent the original concentration of C6H5NH3* in the water. Based on the given values, set up the ICE table in order to determine the unknown. C6H5NH₂(a+ H₂O(1) OH¯(aq) +C6H5NH3†(a

Consider the following system at equilibrium at constant T: 2SO2 (g) + O2 (g) <=> 2SO3 (g) If you want to decrease the amount of SO3 in the container you could leave the volume unchanged (const T) add SO2 decrease the volume (const T) add O2 increase the volume (const T)

Which of the following conditions is/are met at the equivalence point of the titration of a monoprotic weak base with a strong acid? 1. The moles of acid added from the buret equals the initial moles of weak base. 2. The volume of acid added from the buret must equal the volume of base titrated. 3. The pH of the solution is less than 7.00. A 3 only B 1 only C 2 only D 1 and 3

How many grams of solid potassium hypochlorite should be added to 2.00 L of a 9.63×10-2 M hypochlorous acid solution to prepare a buffer with a pH of 8.230 ? grams potassium hypochlorite =

The value of the Solubility Product Constant for copper(II) sulfide is Write the reaction that corresponds to this Ksp value. Ksp values are found by clicking on the "Tables" link. Be sure to specify the state of each reactant or product. If a box is not needed leave it blank.

Which statement is NOT true about a strong electrolyte? Completely dissociates in solution An example is KOH Conducts electricity Dissociates completely to ions An example is NH3

Carbon disulfide and oxygen react to form carbon dioxide and sulfur dioxide, like CS₂ (g)+3O₂ (g) - CO₂ (g)+2SO₂(g) Suppose a mixture of CS₂, O₂, CO₂ and SO₂ has come to equilibrium in a closed reaction vessel. Predict what change, if any, the perturbations in the table below will cause in the composition of the mixture in the vessel. Also decide whether the equilibrium shifts to the right or left.

Nickel and carbon monoxide react to form nickel carbonyl, like this: Ni(s) +4 CO(g)-Ni (CO) 4(9) At a certain temperature, a chemist finds that a 6.3 L reaction vessel containing a mixture of nickel, carbon monoxide, and nickel carbonyl at equilibrium has the following composition: Calculate the value of the equilibrium constant K, for this reaction. Round your answer to 2 significant digits.

A solution of oxalic acid dihydrate (H2C2O4.2H2O) with a known concentration of 0.400 M H₂C2O4 2H₂O is titrated with a 0.333 M NaOH solution. How many L NaOH are required to reach the second equivalence point with a starting volume of 65.0 mL H₂C2O4 2H2O, according to the following balanced chemical equation

Consider the reaction given by the following equation: A+B 2C The initial concentrations are [A] = 1.00 M, [B] = 1.00 M, and [C] = 2.00 M. At 25°C, Kc =1.00. Calculate the equilibrium concentration of C. A. 2.00 M B. 0.66 M C. 1.33 M D. 1.67 M E. 2.66 M

A substance is composed of a metal cation and a hydroxide anion. When dissolved in water, it completely dissociates into cations and anions. The substance is a weak acid weak base strong acid strong base

The following reaction is at equilibrium: PCI 5(g) → PC|3(g) + Cl2(g) The equilibrium concentrations are [PCI5(g)] = 0.015 M, [PC13(g)] = 0.220 M, and [Cl2(g)] = 0.471 M. Which of the following is the correct value for the equilibrium constant, Keq, for this reaction? a) 0.676 Ob) 6.91 Oc) 1.45 x 10-1 d) 0.015

The OH- concentration in an aqueous solution at 25 °C is 6.1 × 10-5. What is [H+]?

Assuming equal concentrations of conjugate base and acid, which one of the following mixtures is suitable for making a buffer solution with an optimum pH in the range of 9.1- 9.5? NaNO3/HNO3 KCN/HCN (Ka = 4.9 x10-10) CH3NH2/CH3NH3CI (Ka = 2.3 x 10-11) NaNO2/HNO2 (Ka = 4.6 x 10-4) NaOCN/HOCN (Ka = 2.0 x 10-4)

A solution has a pH of 13.20. We can conclude that A) the solution is very acidic. B) the solution is only slightly acidic. C) the solution is only slightly basic. D) The solution is very basic.

For each chemical reaction in the table below, decide whether the highlighted reactant is a Brønsted-Lowry acid, a Brønsted-Lowry base, or neither.

If a liquid is sealed in a container, kept at a constant temperature, how does vapor pressure change over time? The rate of liquid into the gas state will eventually equal the rate of gas returning to the liquid state. It is a closed container, so the molecules will remain liquid. There is no temperature change, so there will be no change to the system. The number of molecules of liquid and gas wil eventually equal one another.

Estimate the value of the equilibrium constant at 680 K for each of the following reactions. 2 NO2 (9) N2O4 (9) Standard Thermodynamic Quantities for Selected Substances at 25 °C Substance Af H (kJ mol-¹) S° (J K ¹ mol ¹) NO₂(g) 33.2 240.1 N2O4 (9) 9.16 304.4

CaF₂ (s) Ca2+ (aq) + 2F- (aq) HF(aq) H+(aq) + F- (aq) The dissolution of calcium fluoride is represented by the equilibrium system above at 25°C. The F ion is produced when the weak acid HF dissociates. If solid calcium fluoride is added to equal volumes of the following solutions at 25°C, in which solution will the most calcium fluoride dissolve? Pure distilled water 1 M HNO3(aq) 1 M NaOH(aq) K 3.9 x 10-11 A saturated aqueous CaF₂ solution K=6.8 x 104

AgCl(s) Ag+ (aq) + Cl (aq) KC= 1.8 x 10-10 Shown above is information about the dissolution of AgCl(s) in water at 298 K. In a chemistry lab a student wants to determine the value of s, the molar solubility of AgCl by measuring [Ag*] in a saturated solution prepared by mixing excess AgCl and distilled water. How would the results of the experiment be altered if the student mixed excess AgCl with tap water (in which [CI] = 0.010 M) instead of distilled water and the student did not account for the Cl in the tap water? The value obtained for K, would be too small because Cl(aq) ions would be attracted to the Ag+ ions in the AgCl crystals, thus preventing water molecules from reaching the crystals. The value obtained for K would be too small because less AgCl(s) would dissolve because of the common ion effect due to the Cl(aq) already in the water. The value obtained for K would be too large because more AgCl(s) would dissolve because of the attractions between Ag+ ions in the AgCl crystals and the Cl(aq) ions in the water. The results of the experiment would not be altered because 0.010 M is such a small concentration of Cl(aq) ions and thus has no effect on the dissolution of AgCl(s).