Equilibrium Questions and Answers

Consider the reaction at 25 °C A (g) + B (s) + 2 C (g) What is the value of ke for the reaction at the same temperature?

An electrolyte undergoes ninety percent ionization to reach equilibrium in aqueous solution. Which of the following statement is true for the ionization equilibrium in aqueous solution? K> 1, ionization does not favor reactants or products CA. K>1, ionization favors products B. OC. K<1, ionization does not favor reactants or products K< 1, ionization favors reactants OD.' EK> 1, ionization favors reactants

Consider the reaction: 4 A (g) + 3B (g) ---- 2 C (g) + 5 E (g). The reaction is initiated with 0.60 M in A, 0.45 M in B and 0.50 M in E in a 1.0 L vessel. At equilibrium, the value of [A] = 0.36 M. What is the equilibrium value of [E]? 0.75 M 0.26 M 0.80 M 0.86 M 0.50 M

Consider the reaction N₂O4 (g) - NO2 (g) where Kc = 0.20 at 25 °C. If 0.40 mol NO₂ and 0.80 mol N₂04 are introduced into a 1.0 L flask at 25 °C, what change in concentrations (if any) will occur in time? A. [NO₂] will decrease and [N₂04] will decrease. B. [NO₂] will increase and [N₂04] will decrease. C. [NO₂] will increase and [N204] remain unchanged. D. [NO₂] will decrease and [N₂04] will increase. E. [NO₂] and [N2O4] remain unchanged.

An aqueous solution has a hydrogen ion concentration of 1×105 M (10-5 M). (1) What is the hydroxide ion concentration in this solution? (2) What is the pOH of this solution? (3) What is the pH of this solution?

For the equilibrium CH₂(g) + 2 H₂S(g) = CS, (g) +4 H₂(g), the concentrations at equilibrium are [CH4] 0.3322 M, [H₂S] = 0.6644 M, [CS2] = 0.0678 M, and [H₂] = 0.2712 M at 1400.0 K. Calculate Kc. 6.00 4.00 × 10² 2.50 x 10-3 0.167 0.694

What is the pH of a 0.50 M solution of HCIO if Ka = 3.0 x 10-8 for HCIO ? What type of solution is this?

Diagram the following acid/base reaction and determine conjugate acid/conjugate base/acid/base. HCI + HO → H₂O + CI™

25. Write equilibrium constant expressions for the following reactions: a. 2 PBr3(g) + 3 Cl2(g) = 2 PC13(g) + 3 Br2(g) b. 4 KO2() + 2 H₂O(g) = 4 KOH(s) + 3 O2(g) 26 The equilibrium constant K- 1 103

Enter your answer in the provided box. Use the following information to calculate the AH Mg(s) → Mg(g) F₂(g) → 2 F(g) Mg(g) → Mg (g) + e¯ Mg (g) → Mg2+(g) + e¯ F(g) +eF(g) Mg(s) + F₂(g) →→ MgF₂(s) AHⓇ lattice 3 KJ lattice of MgF2: AH = 148 kJ AH = 159 kJ AH = 738 kJ AH = 1450 kJ AH = -328 kJ AH =-1123 kJ

Select all of the TRUE statements concerning a solution formed by mixing 500. mL of 0.000115 M Fe(NO3)2 with 500. mL of 2.74 x 10-6 M LIOH? Solubility guidelines are found with the formulas at the top of the exam. Ksp(precipitate) = 4.1 x 10-15 A precipitate will form. No precipitate will be formed. A precipitate will form even if the concentration of LiOH is decreased by a factor of 10. A precipitate will form if the concentration of LiOH is increased by a factor of 10. There is not enough information to make any of these claims.

Determine the pH of a buffer consisting of 0.399 M HCN and 0.321 M LiCN. Remember that only the decimals in a pH count as significant figures. Please enter your answer with three decimal places.

Read the statements and answer the question that follows: Assertion (A): After adding a hot substance to a cold substance, the final temperature of the mixture is uniform throughout the mixture. Reason (B): The molecules of the mixture will possess the same average kinetic energy. Which of the following is true for the above statements? Both (A) and (R) are true, but (R) is not the correct explanation of (A). Both (A) and (R) are true, and (R) is the correct explanation of (A). (A) is false, and (R) is true. (A) is true, and (R) is false.

Which of the following is true for phase change? During phase change, the temperature remains constant. During phase change, the pressure remains constant. During phase change, the energy remains constant. During phase change, the volume remains constant.

For each reaction below, label the acid, base, conjugate acid, and conjugate base, then connect each conjugate pair with a line: a. HCO₂H(aq) + NH3(aq) <--> HCO₂ (aq) + NH4*(aq) b. C6H5COOH(aq) + OH(aq) <--> H₂O(aq) + C6H5COO(aq)

The equilibrium constant, K, for the following reaction is 1.29×10-2 at 600 K. COC1₂(g) CO(g) + Cl₂(g) An equilibrium mixture of the three gases in a 1.00 L flask at 600 K contains 0.221 M COCl2, 5.34×10-² M CO and 5.34×10-² M Cl₂. What will be the concentrations of the three gases once equilibrium has been reestablished, if 4.15×10-²mol of CO(g) is added to the flask?

15. Write the equilibrium expression for the following reaction. Based upon the value of K, would you expect there to be more or less product in the equilibrium mixture? Why? CaO(s) + CH₂(g) + 2H₂O(g) -> CaCO3(s) + 4H₂(g) Kp = 2344

4. Suppose that you have two acids. Acid A has a larger K₂ than Acid B. Which of the following statement(s) about Acid A is/are true? A. Acid A has a higher pH than Acid B. B. Acid A dissociates more than Acid B. C. Acid A is a strong acid that dissociates completely. D. Acid A is a stronger acid than Acid B.

In a 0.3000M solution of a monoprotic weak acid (HA), [H] = 2.35 X 10-4 M. What is the dissociation constant (K₂) of this acid? The equilibrium constant of [H*] and of the corresponding anion are both equal to 2.35 X 10-4 M What is the equilibrium concentration of the acid [HA] to four significant figures? ___M (The equilibrium value of [HA] is the initial value minus the equilibrium value of [H*].) The formula for the dissociation constant is K₂=([H]X [A]) + [HA] Substitute the known values and calculate. Give your answer in scientific notation and to three significant digits. K₂= Type your answer here. X 10-7

Which of the following statement(s) about the acid dissociation constant (K₂) of acids is/are true? A. Strong acids have larger acid dissociation constants than weak acids. B. Weak acids have larger acid dissociation constants than strong acids. C. Strong and weak acids have about the same acid dissociation constant values. D. Weak acids have smaller acid dissociation values than strong acids.

In a 0.2000M solution of a monoprotic weak acid (HA), [H*] = 9.86 X 104 M. What is the dissociation constant (K₂) of this acid? The equilibrium constant of [H*] and of the corresponding anion are both equal to 9.86 X 104 M What is the equilibrium concentration of the acid [HA] to four significant figures? Type your answer here. (The equilibrium value of [HA] is the initial value minus the equilibrium value of [H*].) The formula for the dissociation constant is K₂ = ([H*] X [A]) + [HA] Substitute the known values and calculate. Give your answer in scientific notation and to three significant digits. Ka = Type your answer here. X 10-6

Calculate the pH of each of the solutions in the question above. Fill in the blanks as you answer the question. [H+]= 3.3 x 10-5 [H+]=4.0 x 108 [H+]= 7.2 x 10-11 [H+]= 8.2 x 10-4

__Ba3N2 + __H₂O⇒ _Ba(OH)2 + __NH3 Which has the correct coefficients? Answer will have the number in correct order. A 1,1,1,1 B 1,3,3,2 C) 1,6,3,2 D) 2,3,2,2

The specific heat of water is 4.2 J/g °C. How much heat is required to raise the temperature of 100 g of water by 5°C? Q = m.C.ΔT A 2100 J B 84J C 500 J D 119J

A 0.1000 M solution of hydrofluoric acid (HF) has a pH of 2.10. Calculate the value of K, for hydrofluoric acid. Fill in the blanks as you answer the question. If you need to make a number superscript, put a in front of the number. For example, x² would be written as x^2. equilibrium [H*] = equilibrium [F] = equilibrium [HF] = K₂ =

When acid (H+) is added to a dihydrogenphosphate lon-hydrogenphosphate lon (H₂PO/HPO,2) buffer system, the acid reacts with A H₂Pto produce HPO,²- B. HPO, to produce H₂PO₂ C. H₂Pto produce water D. H₂to produce HPO,²-

4HCI(g) + O₂(g) → 2H₂O(l) + Cl₂(g) + 113kJ Which action will drive the reaction at equilibrium to the right? A. Heating the equilibrium mixture B. Decreasing the oxygen concentration C. Increasing the system's pressure D. Adding water to the system

[3A,1T] A buffer solution is prepared by dissolving 1.80 g of benzoic acid, C6H5COOH, and 1.95 g of sodium benzoate, NaC6H5COO, in 800 mL of water. Calculate the pH of the buffer solution.

Methanol reacts with acidic permanganate ions as shown below: 5 CH₂OH(l) + 2 MnO₂ (aq) + 6 H+ (aq) → 5 CH₂O(l) + 2 Mn²+ (aq) + 8 H₂O(1) (a) Assign oxidation numbers to all atoms/ions. (b) Which atom/ion is oxidized? Label the oxidation above the equation. (c) Which atom/ion is reduced? Label the reduction below the equation.

The average molecular speed in a sample of Ar gas at a certain temperature is 401 m/s. The average molecular speed in a sample of CH4 gas is ___ m/s at the same temperature.

You wish to make a 0.133 M nitric acid solution from a stock solution of 12.0 M nitric acid. How much concentrated acid must you add to obtain a total volume of 150 mL of the dilute solution?

Write a net ionic equation to show that nitric acid, HNO3, behaves as an acid in water.

An experiment is conducted using nitrogen monoxide and bromine reacted to form nitrosyl bromide. Calculate Keq for the reaction using the following equation data. 2NO(g) + Br₂(g) = 2NOBr(g) [NOBr] =0.0474 mol/L [NO]= 0.312 mol/L. [Br₂] = 0.259 mol/L Keq

POSSIBLE POIN Use the balanced equation below to answer the following question about the reaction of calcium with hydrochloric acid that produces hydrogen. Ca + 2HCI = Ca + 2Cl + H₂ What is the theoretical yield in liters of hydrogen at STP if 52 g of hydrochloric acid are completely reacted? 1.8L 16L 23L 60L

Calculate the △H°rxn for the decomposition of calcium carbonate to calcium oxide and carbon dioxide according to the following chemical equation: CaCO₃(s) → CaO(s) + CO₂(g) △Hrxn= Σm△H⁰ f products - Σn△H⁰ f reactants △H° f (CaCO₃(s)] = -1206.9 kJ/mol △H⁰ f [CaOS)] = -635.1 ks/mol △H⁰ f (CO₂) = -393.5 kJ/mol

A chemistry graduate student is given 500, mL of a 0.90 M dimethylamine ((CH₃)₂NH) solution. Dimethylamine is a weak base with Kb=5.4 x 10-⁴. What mass of (CH₃)₂NH₂ Br should the student dissolve in the (CH₃)₂NH solution to turn it into a buffer with pH = 10.87 ? You may assume that the volume of the solution doesn't change when the (CH₃)₂NH₂ Br is dissolved in it.

A student prepares a solution by combining 100 ml of 0.30 M HNO₂ (aq) and 100 mL of 0.30 M KNO₂ (aq). Which of the following equations represents the reaction that best helps to explain why adding a few drops of 1.0 M HCl (aq) does not significantly change the pH of the solution? (A) K+(aq) + Cl–(aq) → KCI(s) (B) H+(aq) + OH–(aq) → H₂O(l) (C) HNO₂(aq) → H+(aq) + NO₂– (aq) (D) H+(aq) + NO₂– (aq) → HNO₂(aq)

The reaction AB2C(g) B2(g) + AC(g) reached equilibrium at 900 K in a 3.00 L vessel. At equilibrium 0.0570 mol of AB2C, 0.0100 mol of B2, and 0.0590 mol of AC were detected. What is the equilibrium constant at this temperature for this system?

HA is a weak unknown acid with a Ka = 2.50 x 10^-1 If 1.00 moles of HA is dissolved in water, then use the ICE method to determine the equilibrium concentration of A+ (aq). Report your answer to two sig figs without a unit label.... don't use scientific notation.

Which of the following mathematical expressions is the Henderson-Hasselbalch equation? (A) pH = pka + log(]OH‾]/[H3O⁺]) (B) pH = pka + log([conjugate base]/[acid]) (C) pka = pH + log([conjugate base]/[acid]) (D) pH = pka + log([conjugate base]/[acid])

Use the reaction below to answer the question. PCI5 (g)---> PC|3 (g) + Cl₂(g) (△H=67kJ/mol) If the reaction is at equilibrium, and the temperature of the reaction is increased, what will happen? The amount of PCl5 will increase The reaction will shift to the left. The amount of Cl2 will decrease. More Cl₂ will form The amount of PCl3 will decrease.

Nickel carbonate is being precipitated out of a 1.00 L solution. If the concentration of dissolved nickel is 0.248, what mass (in micrograms) of sodium carbonate (Na2CO3) must be added for precipitation to begin? The Ksp of nickel carbonate is 1.42 x 10-7. 1 gram = 1 x 100 micrograms

When a solution contains a weak acid and its conjugate base or a weak base and its conjugate acid, it will be a buffer solution. Buffers resist change in pH following the addition of acid or base. A buffer solution prepared from a weak acid (HA) and its conjugate base (A) is represented as: HA (aq) = H+ (aq) + A- (aq) What is the pH of a buffer prepared by adding 0.708 mol of the weak acid HA to 0.406 mol of NaA in 2.00 L of solution? The dissociation constant Ka of HA is 5.66 x 10-7.Express the pH numerically to three decimal places. What is the pH after 0.195 mol of NaOH is added to the buffer from Part A? Assume no volume change on the addition of the base. Express the pH numerically to three decimal places.

PCl5(g) ---> PCl3(g) + Cl2(g) At equilibrium if the presure of system is decreased then select which of the following is not correct. Concentration of all decreases. Degree of dissociation of PCl5 increases. Vapour density of mixture decreases. Vapour density of mixture increases.

The equilibrium constant for the reaction below is 1.3 × 10^40 at 536 °C. H2 (g) + ½O2 (g) → H₂0 (g) Kc(536 °C)=1.3 x 10^40 What can be stated about the relative equilibrium distribution for this mixture? The mixture contains relatively equal amounts of H2, O2 and H20 at equilibrium. The mixture contains predominantly O2 at equilibrium. The mixture contains predominantly H2 and O2 at equilibrium. The mixture contains predominantly H₂at equilibrium. The mixture contains predominantly H₂ at equilibrium..

Find the pH of a baking soda solution for which the hydrogen ion concentration is 7.74 x 10-3. Round to the nearest tenth.

Identify the Bronsted acid and base on the left and their conjugate partners on the right in the acid-base reaction below. [Al(H2O)6]^3+(aq) + OH^-(aq) ⥨ [Al(H2O)5OH]^2+(aq) + H2O(l) [Al(H2O)6]^3+ (aq) acid base OH^-(aq) acid base [AI(H2O)5OH]^2+(aq) conjugate acid conjugate base

The reaction 2A(g) ⇌ B(g) has a value of Kp = 0.301. If the reaction is initiated with 3.0 atm of gas A, and 1.0 atm of gas B, which direction will the reaction proceed to reach equilibrium? a. the system is already at equilibrium b. to the right, creating more product c. to the left, creating more reactant d. the pressure of all gasses will increase e. the pressure of all gasses will decrease

Designate the conjugate partners on the right side of this reaction: NH₄⁺(aq) + F‾(ag) → NH₃(aq) + HF(ag) a. conjugate acid: HF(aq) b. conjugate acid: NH₃(aq) c. conjugate base: HF(aq) d. conjugate base: NH₃(aq)

Enzymes function as a catalyst by: a. changing the equilibrium constant b. lowering the overall energy change in a reaction c. increasing the time it takes for a reaction to take place d. lowering the activation energy of a reaction