1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Vilka [71]
3 years ago
6

determine the ph of a buffer that is 0.55 M HNO2 and 0.75 M KNO2. tha value of Ka for HNO2 is 6.8*10^-4

Chemistry
1 answer:
Mariana [72]3 years ago
3 0

Answer:

pH = 3.3

Explanation:

Buffer solutions minimize changes in pH when quantities of acid or base are added into the mix. The typical buffer composition is a weak electrolyte (wk acid or weak base) plus the salt of the weak electrolyte. On addition of acid or base to the buffer solution, the solution chemistry functions to remove the acid or base by reacting with the components of the buffer to shift the equilibrium of the weak electrolyte left or right to remove the excess hydronium ions or hydroxide ions is a way that results in very little change in pH of the system. One should note that buffer solutions do not prevent changes in pH but minimize changes in pH. If enough acid or base is added the buffer chemistry can be destroyed.

In this problem, the weak electrolyte is HNO₂(aq) and the salt is KNO₂(aq). In equation, the buffer solution is 0.55M HNO₂ ⇄ H⁺ + 0.75M KNO₂⁻ . The potassium ion is a spectator ion and does not enter into determination of the pH of the solution. The object is to determine the hydronium ion concentration (H⁺) and apply to the expression pH = -log[H⁺].

Solution using the I.C.E. table:

              HNO₂ ⇄    H⁺   +   KNO₂⁻

C(i)        0.55M       0M      0.75M

ΔC            -x            +x          +x

C(eq)  0.55M - x       x     0.75M + x    b/c [HNO₂] / Ka > 100, the x can be                                    

                                                             dropped giving ...

           ≅0.55M        x       ≅0.75M        

Ka = [H⁺][NO₂⁻]/[HNO₂] => [H⁺] = Ka · [HNO₂]/[NO₂⁻]

=> [H⁺] = 6.80x010⁻⁴(0.55) / (0.75) = 4.99 x 10⁻⁴M

pH = -log[H⁺] = -log(4.99 x 10⁻⁴) -(-3.3) = 3.3

Solution using the Henderson-Hasselbalch Equation:

pH = pKa + log[Base]/[Acid] = -log(Ka) + log[Base]/[Acid]

= -log(6.8 x 10⁻⁴) + log[(0.75M)/(0.55M)]

= -(-3.17) + 0.14 = 3.17 + 0.14 = 3.31 ≅ 3.3

You might be interested in
A particular power source creates electricity through the use of giant magnets that are rotated to create a flow of electrons. T
Sloan [31]
From the electric generator to electric outlets in homes
6 0
2 years ago
Read 2 more answers
What is the total number of atoms in molecule hno3?
forsale [732]
5. 1 hydrogen, 1 Nitrogen, 3 oxygen
8 0
2 years ago
Calculate the maximum volume in ml of 0.15M HCl that each of the following antacid formulations would be expected to neutralize.
vlada-n [284]

a. 34 mL; b. 110 mL

a. A tablet containing 150 Mg(OH)₂


Mg(OH)₂ + 2HCl ⟶ MgCl₂ + 2H₂O


<em>Moles of Mg(OH)₂</em> = 150 mg Mg(OH)₂ × [1 mmol Mg(OH)₂/58.32 mg Mg(OH)₂

= 2.572 mmol Mg(OH)₂


<em>Moles of HCl</em> = 2.572 mmol Mg(OH)₂ × [2 mmol HCl/1 mmol Mg(OH)₂]

= 5.144 mmol HCl


Volume of HCl = 5.144 mmol HCl × (1 mmol HCl/0.15 mmol HCl) = 34 mL HCl


b. A tablet containing 850 mg CaCO₃


CaCO₃ + 2HCl ⟶ CaCl₂ + CO₂ + H₂O


<em>Moles of CaCO₃</em> = 850 mg CaCO₃ × [1 mmol CaCO₃/100.09 mg CaCO₃

= 8.492 mmol CaCO₃


<em>Moles of HCl</em> = 8.492 mmol CaCO₃ × [2 mmol HCl/1 mmol CaCO₃]

= 16.98 mmol HCl


Volume of HCl = 16.98 mmol HCl × (1 mL HCl/0.15 mmol HCl) = 110 mL HCl


5 0
3 years ago
Simplify the numercial expression 13-2x5
Tema [17]

Answer:

3

Explanation:

2x5 is 10 then 13-10 is 3

4 0
3 years ago
Read 2 more answers
Which conditions must be met for two triangles to be similar
lbvjy [14]
The included angle, i.e. If two pairs of sides of two triangles are in proportion, and the included angles are equal, then the triangles are similar.
7 0
2 years ago
Other questions:
  • HELP ASAP WILL AWARD 60 Points
    15·1 answer
  • Equatio of table perparing for long trip​
    9·1 answer
  • Which of the following best explains the trend in ionization energy across a period?
    12·2 answers
  • The organ system that moves air into, around, and out the body
    13·1 answer
  • Which of these solutes raises the boiling point of water the most?
    10·2 answers
  • The energy acquired in the light-dependent reactions is used in the light-independent reactions to build glucose molecules. How
    7·1 answer
  • Which of these are broken down during chemical,but not physical,changes
    5·1 answer
  • 1. The pressure of a gas is 100.0 kPa and its volume is 500.0 ml. If the volume increases to 1,000.0 ml, what is the new pressur
    13·1 answer
  •  why don't we ever see solid or liquid oxygen on earth?
    14·1 answer
  • How many moles would be in 14.6 g of Sodium?
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!