# chemistry

A buffer is prepared by dissolving .0250 mol of sodium nitrite, NaNO2, in 250.0 mL of .0410 M nitrous acid, HNO2. Assume no volume change after HNO2 is dissolved. Calculate the pH of this buffer.

My book does a poor job of explaining buffers and I'm really lost on the concept. Any directions and explanations would be appreciated.

Use the Henderson-Hasselbalch equation.
pH = pKa + log [(base)/(acid)]/

1. 👍 0
2. 👎 0
3. 👁 269
1. [HNO2] = .0410 M
[NaNO2] = .0250 mol / .250 L = .100 M
[H+] = Ka x [HA (weak acid)] / [A- (conj. base)]
Ka = 6.0 x 10^-4 (a given constant)
[H+] = (6.0 x 10^-4) x [.041]/[.100]
= 2.5 x 10^-4 M.
pH = -Log[H+] -- pH = -log[2.5 x 10^-4]
pH = 3.61

1. 👍 0
2. 👎 0
posted by Josh

## Similar Questions

1. ### science

Sodium nitrite is prepared by a reaction of sodium nitrate and carbon: NaNO3 + C → NaNO2 + CO2 Calculate the masses of reactants needed for the preparation of 10 g of NaNO2. Carbon is used in 10% excess. The atomic/molecular

asked by Anonymous on March 23, 2017
2. ### Analytical Chemistry

A 500-mL buffer was prepared and it is 0.300 M in nitrous acid (HNO2 , Ka = 4.0 x 10-4) and 0.200 M in sodium nitrite, NaNO2. What will be the pH of this solution after adding 1.00 mL of 6.00 M HCl?

asked by Allene on August 26, 2014
3. ### chemistry

Solid sodium nitrate can be decomposed to solid sodium nitrite and oxygen gas. If the percentage yield for the reaction is 80.4%, calculate the grams of sodium nitrite that will result from the decomposition of 955grams of sodium

asked by lama on May 15, 2009
4. ### school

What is the pH of 0.1 M formic acid solution? Ka=1.7„e10-4? What is the pH value of buffer prepared by adding 60 ml of 0.1 M CH3COOH to 40 ml of a solution of 0.1 M CH3COONa? What is the pH value of an acetate buffer (pK=4.76)

asked by alshammari on December 11, 2011
5. ### Chemistry

If a researcher needs 0.50 L of 3.0 M nitrite buffer at pH 3.00, then she knows that the concentration of nitrous acid (conjugate acid) plus the concentration of nitrite anion (conjugate base) must equal 3.0 M. She must then

asked by Mike on April 11, 2011
6. ### CHEMISTRY

A buffer was prepared by dissolving 0.40 mol of benzoic acid (Ka=6.3*10^-5) and 0.50 mol of sodium benzoate in sufficient pure water to form a 1.00 L solution. To this solution was added 30.00 mL of 2.00 M HCl solution. What was

asked by Sally on April 3, 2018
7. ### Chemistry - acid base

What volume of 10.0 M NaOH is needed to prepare a buffer with a pH of 7.79 using 31.52 g of TrisHCl? ( Tris. At 25 ∘C, Tris has a pKb of 5.91 ) a) The buffer from Part A is diluted to 1.00 L. To half of it (500. mL), you add

asked by K on March 9, 2018
8. ### Chemistry

How would you calculate the pH of the buffer if 1.0mL of 5.0M NaOH is added to 20.0mL of this buffer? Can someone please explain to me how to do B and C step by step so I could understand it clearly? :) Say, for example, that you

asked by Airin on March 4, 2014
9. ### Chemistry

How would you calculate the pH of the buffer if 1.0mL of 5.0M NaOH is added to 20.0mL of this buffer? Can someone please explain to me how to do B and C step by step so I could understand it clearly? :) Say, for example, that you

asked by Airin on March 5, 2014
10. ### Chemistry ! Need help.

A buffer prepared by dissolving oxalic acid dihydrate (H2C2O4·2H2O) and disodium oxalate (Na2C2O4) in 1.00 L of water has a pH of 5.007. How many grams of oxalic acid dihydrate (MW = 126.07 g/mol) and disodium oxalate (MW =

asked by Owen on September 20, 2015

More Similar Questions