PH Chemistry Assignment Help

15 #8

Which of the following is correct for a 6.5e-05 M solution of Mg(OH)2 at 25 C?

15 #11

What is the pH of a solution with a hydronium-ion concentration of 6.9e-04 M?

15#12

What is the pH of a solution with a hydroxide ion concentration of 6.6e-04 M?

15#13

A solution of lye (sodium hydroxide, NaOH) has a hydroxide ion concentration of 0.083 M. What is the pH at 25 C?

15#14

A 1.00-L aqueous solution contained 9.59 g of barium hydroxide, Ba(OH)2. What was the pH of the solution at 25 C?

15#16

A sample of lemon juice has a hydronium-ion concentration equal to 4.10e-03 M. What is the pH of this sample?

15#17

A sample of grape juice has a pH of 4.36. What is the hydroxide-ion concentration of this solution?

15#18

A 2.12 g sample of a mixture of sodium hydrogen carbonate and potassium chloride is dissolved in 25.00 mL of 0.437 M H2SO4. Some acid remains and is titrated with 24.91 mL of 0.108 M NaOH. What is the percent NaHCO3 in the original sample?

15#19

A 2.500 g sample of a mixture of sodium carbonate and sodium chloride is dissolved in 25.00 mL of 0.713 M HCl. Some acid remains after the treatment of the sample. If 33.7 mL of 0.108 M NaOH were required to titrate the excess hydrochloric acid, how many moles of sodium carbonate were present in the original sample?

15#21

A solution contains 0.450 g of ethylamine, C2H5NH2, per 100.0 mL of solution. Electrical conductivity measurements show that 0.37 % of the ethylamine has reacted with water. What is the pH of the solution?

16#1

Heavy metal azides, which are salts of hydrazoic acid, HN3, are used as explosive detonators. A solution of 0.017 M hydrazoic acid has a pH of 3.25. What is the Ka for hydrazoic acid?

16#2

A chemist wanted to determine the concentration of a solution of lactic acid, HC3H5O3. She found that the pH of the solution was 3.12. What was the concentration of the solution? The Ka of lactic acid is 1.4 x 10-4.

16#3

Trimethylamine, (CH3)3N, is a gas with a fishy, ammonia-like odor. An aqueous solution that is 0.40 M trimethylamine has a pH of 11.73. What is the Kb for trimethylamine?

16#4

What is the concentration of hydroxide ion in a 0.26 M aqueous solution of hydroxylamine, NH2OH? The Kb for hydroxylamine is 1.1 x 10-8.

16#6

What is the pH of a 0.26 M solution of methylammonium chloride, CH3NH3Cl? The Kb for methylamine, CH3NH2, is 4.4 x 10-4.

16#7

Calculate the degree of ionization of a solution of 0.47 M HCHO2 (formic acid) and 0.19 M HCl.

16#8

What is the pH of a solution that is 0.13 M KOCN and 0.15 M HOCN (cyanic acid)?

16#9

A buffer is prepared by adding 115 mL of 0.36 M NH3 to 301 mL of 0.15 M NH4NO3. What is the pH of the final solution?

16#10

What is the pH of a buffer solution that is 0.10 M propionic acid and 0.18 M sodium propionate?

16#11

What is the pH of a solution in which 59 mL of 0.10 M NaOH is added to 25 mL of 0.10 M HCl?

16#12

What is the pH at the equivalence point when 24 mL of 0.43 M hydroxylamine is titrated with 0.20 M HCl?

16#14

What is the pH of a 0.22 M aqueous solution of zinc chloride, ZnCl2?

The acid ionization of hydrated zinc ion is

Zn(H2O)62+(aq) + H2O(l) Zn(H2O)5OH–(aq) + H3O+(aq)

16#15

Calculate the pH of a solution made up from 2.1 g of potassium hydroxide dissolved in 138 mL of 0.12 M perchloric acid. Assume the change in volume due to adding potassium hydroxide is negligible.

16#16

Sodium benzoate is a salt of benzoic acid, C6H5COOH. A 0.23 M solution of this salt has a pOH of 5.22 at room temperature. What is the Ka value for benzoic acid?

16#19

A 25.00-mL sample contains 0.547 g of NaHCO3. This sample is used to standardize an NaOH solution. At the equivalence point, 14.03 mL of NaOH has been added. Calculate the pH at the equivalence point.

16#20

A chemist needs a buffer with pH 3.02. How many milliliters of pure formic acid (density = 1.220 g/mL) must be added to 366 mL of 0.0765 M NaOH solution to obtain such a buffer?