Question

In: Chemistry

A 230.0 −mL buffer solution initially contains 2.0×10−2 M of HCHO2 and 2.0×10−2 M of NaCHO2....

A 230.0 −mL buffer solution initially contains 2.0×10−2 M of HCHO2 and 2.0×10−2 M of NaCHO2. What mass of the correct reagent should you add?

Solutions

Expert Solution

HCHO2      =     H^+    +    CHO2^-

I(M)    2*10^-2            0              2*10^-2

C(M)         -x                 + x                + x

           -----------------------------------------

As the pH is 4.10, [H+] = 10^-4.10   =   7.94*10^-5 M

                       so, x = 7.94*10^-5 M

Hence equilibrium concentration is  7.94*10^-5 M

    Moles =   7.94*10^-5 M * 0.230 L = 1.8262*10^-5 mol

Mass of reagent = 1.8262*10^-5 mol x 40.00 = 0.00073 g


Related Solutions

A 280.0 −mL buffer solution initially contains 2.5×10−2 M of HCHO2 and 2.5×10−2 M of NaCHO2....
A 280.0 −mL buffer solution initially contains 2.5×10−2 M of HCHO2 and 2.5×10−2 M of NaCHO2. a,) In order to adjust the buffer pH to 4.10, should you add NaOH or HCl to the buffer mixture? The answer is: NaOH b.) What mass of the correct reagent should you add?
50 mL of 2.0 M NaOH is added to a 1.0L buffer solution that is 0.20M...
50 mL of 2.0 M NaOH is added to a 1.0L buffer solution that is 0.20M in HF and 0.20M in KF. The ka for HF is 3.5 x 10^-4. 1. Write the reaction or the buffer only including states and excluding spectator ions. 2. Write the neutralization reaction that occurs after the addition of LiOH including states and excluding spectator ions. 3. Calculate the amount of moles remaining and the final concentration for each component of the solution after...
The following buffer was prepared: 50. mL 2.0 M methylamine (CH3NH2) solution and 50. mL of...
The following buffer was prepared: 50. mL 2.0 M methylamine (CH3NH2) solution and 50. mL of 2.0 M methylamine hydrochloride (CH3NH3Cl) solution. The Kb for methylamine is 4.4 x 10-4. What is the pH of the resulting solution after adding 100 ml of 1.0 M HCl to the original buffer solution? a) 11.12 b) 10.64 c) 12.32 d) 0.48 e) 5.32
The following buffer was prepared: 50. mL 2.0 M methylamine (CH3NH2) solution and 50. mL of...
The following buffer was prepared: 50. mL 2.0 M methylamine (CH3NH2) solution and 50. mL of 2.0 M methylamine hydrochloride (CH3NH3Cl) solution. The Kb for methylamine is 4.4 x 10-4. A. What is the pH of the resulting solution after adding 200 ml of 1.0 M HCl to the original buffer solution? a)11.12                           b) 10.64                       c) 12.32                       d) 0.48                         e) 5.32 B.What is the pH of the resulting solution after adding 50 mL of 1.0 M KOH to the...
The following buffer was prepared: 50. mL 2.0 M methylamine (CH3NH2) solution and 50. mL of...
The following buffer was prepared: 50. mL 2.0 M methylamine (CH3NH2) solution and 50. mL of 2.0 M methylamine hydrochloride (CH3NH3Cl) solution. The Kb for methylamine is 4.4 x 10-4. What is the pH of the resulting solution after adding 100 mL of 1.0 M KOH to the original buffer solution?
The following buffer was prepared: 50. mL 2.0 M methylamine (CH3NH2) solution and 50. mL of...
The following buffer was prepared: 50. mL 2.0 M methylamine (CH3NH2) solution and 50. mL of 2.0 M methylamine hydrochloride (CH3NH3Cl) solution. The Kb for methylamine is 4.4 x 10-4 What is the pH of the resulting solution after adding 100mL of 1.0M HCl to the original buffer solution? A) 11.12 B) 10.64 C) 12.32 D) 0.48 E) 5.32 (Correct Answer: 5.32) Please show work, and explain why.
A) Standard solution contains 2.50 mL 0.20 M Fe3+ (in 0.50 M HNO3), 0.60 mL 2.0...
A) Standard solution contains 2.50 mL 0.20 M Fe3+ (in 0.50 M HNO3), 0.60 mL 2.0 x 10-3 M HSCN (in 0.50 M HNO3), and 6.90 mL of 0.50 M HNO3). Before any reaction occurs, what are the concentrations of Fe3+ and HSCN. What is the concentration of HNO3? B) For the standard solution described in (A) above, - What is the maximum concentration of complex that can be produced by reaction I? - What is the maximum concentration of...
When 100 mL each of 2.0 × 10-4 M Ca2+ and 2.0 × 10-2 M F-...
When 100 mL each of 2.0 × 10-4 M Ca2+ and 2.0 × 10-2 M F- are mixed, what is the remaining Ca2+ ion concentration ? The solubility product constant of CaF2 is 5.3 × 10-9. (Hint: Determine the limiting reactant, the concentration of excess reactant after precipitation, and how the concentration of excess reactant influences the solubility of CaF2).
50. mL 2.0 M methylamine (CH3NH2) solution and 50. mL of 2.0 M methylamine hydrochloride (CH3NH3Cl)...
50. mL 2.0 M methylamine (CH3NH2) solution and 50. mL of 2.0 M methylamine hydrochloride (CH3NH3Cl) solution. The Kb for methylamine is 4.4 x 10-4. What is the pH of the resulting solution after adding 100 mL of 1.0 M KOH to the original buffer solution? 11.12                           b) 10.64                       c) 12.32                       d) 0.48                         e) 5.32
A solution of volume 70.0 mL contains 16.0 mmolHCHO2 and 8.50 mmol NaCHO2. Part A What...
A solution of volume 70.0 mL contains 16.0 mmolHCHO2 and 8.50 mmol NaCHO2. Part A What is the pH of this solution? Express your answer using two decimal places. Part B If 0.25 mmol Ba(OH)2 is added to the solution, what will be the pH? Express your answer using two decimal places. Part C If 1.10 mL of 12 M HCl is added to the original solution, what will be the pH? Express your answer using two decimal places.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT