Concept explainers
(a)
Interpretation:
The value of change in enthalpy for the reaction between NaOH and HCl needs to be determined.
Concept introduction:
For a reaction as follows:
The change in enthalpy can be calculated as follows:
Or, change in enthalpy of reaction is equal to difference in the sum of enthalpy of formation of product and sum of enthalpy of formation of reactants.
(b)
Interpretation:
The value of change in enthalpy for the reaction between NaOH and HF needs to be determined.
Concept introduction:
For a reaction as follows:
The change in enthalpy can be calculated as follows:
Or, change in enthalpy of reaction is equal to difference in the sum of enthalpy of formation of product and sum of enthalpy of formation of reactants.
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Chemistry: Principles and Reactions
- Acids You make a solution by dissolving 0.0010 mol of HCl in enough water to make 1.0 L of solution. a Write the chemical equation for the reaction of HCl(aq) and water. b Without performing calculations, give a rough estimate of the pH of the HCl solution. Justify your answer. c Calculate the H3O+ concentration and the pH of the solution. d Is there any concentration of the base OH present in this solution of HCl(aq)? If so, where did it come from? e If you increase the OH concentration of the solution by adding NaOH, does the H3O+ concentration change? If you think it does, explain why this change occurs and whether the H3O+ concentration increases or decreases. f If you were to measure the pH of 10 drops of the original HCl solution, would you expect it to be different from the pH of the entire sample? Explain. g Explain how two different volumes of your original HCl solution can have the same pH yet contain different moles of H3O+. h If 1.0 L of pure water were added to the HCl solution, would this have any impact on the pH? Explain.arrow_forward2. Barbituric acid, HC,H,N,O, a weak organic acid used to manufacture hypnotic drugs and some plastic, has a Ka of 9.8 x 10 An industrial process requires a 0.25 mol/L solution of Barbituric acid. (a) Calculate the H° and pH of the solution. (b) What is the percent ionization of the acid?arrow_forwardAn acetic acid solution was prepared by dissolving 0.02 moles of acetic acid (HOAC) in water to give a final volume of 1L. The Ka of HOAC s 1.82 x 10°. (a) Calculate the pKa of acetic acid (b) Calculate the pH of the acetic acid solution (c) If 0.012 moles of concentrated NaOH was added to your prepared solution from above, what is the new pH (There is no appreciable chareo ine volumes).arrow_forward
- Like any equilibrium constant, Kw changes with temperature. (a) Given that autoionization is endothermic, how does Kw change with rising T ? Explain with a reaction that includes heat as reactant or product. (b) In many medical applications, the value of Kw at 37°C (body temperature) may be more appropriate than the value at 25°C, 1.0 x 10-14. The pH of pure water at 37°C is 6.80. Calculate Kw, pOH, and [OH-] at this temperature.arrow_forwardCalculate 3OH-4 and pH for each of the following strong base solutions: (a) 0.182 M KOH, (b) 3.165 g of KOH in 500.0 mL of solution, (c) 10.0 mL of 0.0105 M Ca1OH22 diluted to 500.0 mL, (d) a solution formed by mixing 20.0 mL of 0.015 M Ba1OH22 with 40.0 mL of 8.2 * 10-3 M NaOH.arrow_forward(a) Calculate the pH of 0.55 M HCN, if Kₐ=6.2X10⁻¹⁰.(b) Calculate the pOH of 0.044 M HIO₃, if Kₐ=0.16arrow_forward
- 1. The pH of a 0.1 M solution of a monobasic acid P is 1.0 while the pH of a 0.2 M solution of another monobasic acid Q is 3.4. (a) Which, P or Q. is a more concentrated solution? (b) Which, P or Q. is a stronger acid? (c) Which, P or Q, will react faster when a piece of magnesium is dropped to them? (d) Which, P or Q, contains more H'(aq) ions in 50 cm' solution? (e) Which, P or Q or both, can be neutralized by an alkali? (f) Name an instrument to measure the pH of the above solutions. (g) Is Pa strong acid? Explain your answer.arrow_forwardConsider the base hydroxylamine, NH2OH. (a) What is theconjugate acid of hydroxylamine? (b) When it acts as a base,which atom in hydroxylamine accepts a proton? (c) Thereare two atoms in hydroxylamine that have nonbondingelectron pairs that could act as proton acceptors. Use Lewisstructures and formal charges to rationalizewhy one of these two atoms is a much better proton acceptorthan the other.arrow_forward30. In the reaction HCl(aq) + H₂O(l) ⇒Cl¯(aq)+ H3O+ (aq) does water act as a Brønsted-Lowry acid, a Brønsted-Lowry base, or neither, or both? (A) Neither as an acid nor as a base; water is neutral (B) Both an acid and a base. (C) An acid (D) A base (E) Depends temperaturearrow_forward
- Phosphoric acid (H3PO4) is a weak acid naturally found in the body that supports kidney function and also involved in fat storage. It is a weak acid with a Ka value of 6.9×10-3 at STP. (i) Determine the H+ concentration of a 0.25 M solution of phosphoric acid at STP (assume that the acid is monoacidic). (ii) Calculate the pH of the 0.25 M H3PO4 solution at STP. (iii) What effect on the pH of the solution would you expect to observe if the temperature of the weak solution was increased. Give a brief explanation for your answer.arrow_forward(a) Given that Ka for acetic acid is 1.8 x 10-5 and that hypochlorous acid is 3.0 x10-8 , which is a stronger acid? (b) Which is the stronger base, the acetate ion or the hypochlorite ion? (c) calculate the Kb values for the CHCOO- and ClO- .arrow_forwardRank the compounds in each of the following groups in order of increasing acidity or basicity, as indicated, and explain the order you assign. (a) acidity: HCl, HBr, HI (b) basicity: H2O, OH−, H−, Cl− (c) basicity: Mg(OH)2, Si(OH)4, HClO4 (d) acidity: HF, H2O, NH3, CH4arrow_forward
- Chemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage LearningGeneral Chemistry - Standalone book (MindTap Cour...ChemistryISBN:9781305580343Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; DarrellPublisher:Cengage Learning