Overview
- Predict whether the equivalence point of each of the following titrations is below, above, or at pH 7:
a. formic acid titrated with NaOH,
b. calcium hydroxide titrated with perchloric acid,
c. pyridine titrated with nitric acid. - Assume that 30.0 mL of a 0.10 M solution of a weak base B that accepts one proton is titrated with a 0.10 M solution of the monoprotic strong acid HA.
a. How many moles of HA have been added at the equivalence point?
b. What is the predominant form of B at the equivalence point?
c. Is the pH 7, less than 7, or more than 7 at the equivalence point?
d. Which indicator, phenolphthalein or methyl red, is likely to be the better choice for this titration? - How many milliliters of 0.105 M HCl are needed to titrate each of the following solutions to the equivalence point?
a. 45.0 mL of 0.0950 M NaOH
b. 22.5 mL of 0.118 M NH3
c. 125.0 mL of a solution that contains 1.35 g of NaOH per liter - The solubility of two slightly soluble salts of M2+, MA and MZ2, is the same, 4 x 10-4mol/L.
a. Which has the larger numerical value for the solubility product constant?
b. In a saturated solution of each salt in water, which has the higher concentration of M2+?
c. If you added an equal volume of a solution saturated in MA to one saturated in MZ2, what would be the equilibrium concentration of the cation, M2+? - a. If the molar solubility of CaF2 at 35o C is 1.24 x 10-3 mol/L, what is Ksp at this temperature?
b. It is found that 1.1 x 10-2 g SrF2 dissolves per 100 mL of aqueous solution at 25o C. Calculate the solubility product for SrF2.
c. The Ksp of Ba(IO3)2 at 25o C is 6.0 x 10-10. What is the molar solubility of Ba(IO3)2? - A 1.00-L solution saturated at 25o C with lead(II) iodide contains 0.54 g of PbI2. Calculate the solubility-product constant for this salt at 25o C.
- Rainwater is acidic because CO2(g) dissolves in the water, creating carbonic acid, H2CO3. If the rainwater is too acidic, it will react with limestone and seashells (which are principally made of calcium carbonate, CaCO3). Calculate the concentrations of carbonic acid, bicarbonate ion (H2CO3-) and carbonate ion (CO32-) that are in a raindrop that has a pH of 5.60, assuming that the sum of all three species in the raindrop is 1.0 x 10-5 M.
Make sure you obey the following:
- Indicate the number of exercises you are doing. If you accidentally do a problem out of order or separate one part of the problem from the rest, then include a note to the grader, directing the grader to the missed problem or work.
- Show your work. This means showing your steps, not just copying the question from the assignment and the answer from the back of the book. Show everything in between the question and the answer.
- Do not invent your own notation and abbreviations; expect the grader to figure out what you meant. For instance, do not use "#" in your sentence if you mean "pounds" or "numbers". Do not use the "equals" sign ("=") to mean "indicates", "stands for", "leads to", "is related to", or anything else in a sentence; use actual words. The equals sign should be used only in equations and only to mean "is equal to".
- Remember to put your final answer at the end of your work and mark it clearly by, for example, underlining it or drawing a box around it. Label your answer appropriately; if the question asks for measured units, make sure to put appropriate units on the answer. The answer should be in words if the question is a word problem.
- Write your homework as though you're trying to convince someone that you know what you're talking about.