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
Tatiana [17]
3 years ago
13

You need to prepare 1 L of the citric acid/citrate buffer. You have chosen to use Method 1 (see lab presentation). Calculate the

pH of a solution prepared by mixing 300 mL of 0.45 M citric acid acid and 100 mL of 0.65 M NaOH plus water to a final volume of one liter. The Ka of citric acid is 7.24 x 10-4.
Chemistry
1 answer:
prisoha [69]3 years ago
8 0

Answer:

3.11 is the pH of the buffer

Explanation:

The pH of a buffer is obtained using H-H equation:

pH = pKa + log [Conjugate base] / [Weak acid]

<em>Where pH is the pH of the buffer, pKa = -log Ka = 3.14 for the citric buffer and [] could be taken as the moles of each species.</em>

The citric acid,HX (Weak acid), reacts with NaOH to produce sodium citrate, NaX (weak base) and water:

HX + NaOH → H2O + NaX

That means the moles of NaOH added = Moles of sodium citrate produced

And the resulitng moles of HX = Initial moles - Moles NaOH added

<em>Moles HX and NaX:</em>

Moles NaOH = 0.100L * (0.65mol / L) = 0.065 moles NaOH = Moles NaX

Moles HX = 0.300L * (0.45mol / L) = 0.135 moles HX - 0.065 moles NaOH = 0.070 moles HX

Replacing in H-H equation:

pH = 3.14 + log [0.065mol] / [0.070mol]

pH = 3.11 is the pH of the buffer

You might be interested in
Which two formulas represent compounds
SVEN [57.7K]

CO2 ; H20- They are the only ones that, on both sides, combined with another element and bonding of atoms

4 0
3 years ago
Which of the following statements is true? A) This reaction will be spontaneous only at high temperatures. B) This reaction will
viktelen [127]

Answer:

D) This reaction will be nonspontaneous only at high temperatures.

Explanation:

According the equation of Gibb's free energy -

∆G = ∆H -T∆S

∆G = is the change in gibb's free energy

∆H = is the change in enthalpy

T = temperature

∆S = is the change in entropy .

And , the sign of the  ΔG , determines whether the reaction is Spontaneous or non Spontaneous or at equilibrium ,

i.e. ,

if

  • ΔG < 0 , the reaction is Spontaneous
  • ΔG > 0 , the reaction is non Spontaneous
  • ΔG = 0 , the reaction is at equilibrium

The reaction has the value for ∆H = negative , and ∆S = negative ,

Now ,

∆G = ∆H -T∆S

     = ( - ∆H ) - T( - ∆S )

     =  ( - ∆H ) +T(  ∆S )

Now, for making the reaction Spontaneous ΔG = negative ,

Hence ,

The temperature is low, then the value for  ΔG will be negative , i.e. , Spontaneous reaction .

And , vice versa , at higher temperature , the reaction will have ΔG positive , and the reaction will be non -Spontaneous reaction .

The standard free energy of formation will be zero , only for the compounds that are in their pure form ,

Hence , Al(s) will have ΔG = 0 .

7 0
3 years ago
No links please. How many moles of methane (CH4) are in 7.31x10^25 molecules?
ad-work [718]

Answer:

molar mass of methane CH4

= C + 4 H  

= 12.0 + 4 x 1.008

= 12.0 +  4.032

= 16.042g/mol

7.31 x 10^25 molecules x             1 mole  CH4      = 121.43 moles

                                      6.02 x 10^23 CH4 molecules

121.43 moles CH4 are present.

Explanation:

not to certain if this is right or not.. but hope it helps!

4 0
2 years ago
Which units represent destiny? Select all that apply.
ozzi
The basic units for density is \frac{mass}{volume} and any get of units that has those units in the proper place can be considered a density unit.  The ones that has those specifically are A, B, E and F
7 0
3 years ago
Read 2 more answers
72.40% iron,27.60% Oxygen Empirical formula
VARVARA [1.3K]

Explanation:

Fe. O

72.40/ 56 27.60/16

____________________

1.29/1.29 1.725/1.29

_____________________

1. :. 1

<h3>Emperical formula = FeO</h3>
6 0
3 years ago
Other questions:
  • The decay constant of plutonium-239, a waste product from nuclear reactors, is 2.88×10−5year−1. part a what is the half-life of
    8·1 answer
  • A student collected a 40.0 mL sample of H_{2} 2 ​ gas at a temperature of 20.0°C and pressure of 720.0 mmHg. The next day the te
    12·1 answer
  • To what category of elements does an element belong if it is a poor conductor of electricity
    13·1 answer
  • Complete the chart. Atomic Number: 10. 1s
    7·1 answer
  • 27.4 g of Aluminum nitrite and 169.9 g of ammonium chloride react to form aluminum chloride, nitrogen, and water. How many grams
    6·1 answer
  • The vapor pressure of pure water at 250C is 23.77 torr. What is the vapor pressure of water above a solution that is 1.500 m glu
    6·1 answer
  • What is the volume of 50.0 g of table sugar if the density of the sugar is 1.59 gcm3 ?
    13·1 answer
  • 4. Consider the following reaction:
    5·1 answer
  • Which of the following is not a part of the carbon cycle
    9·2 answers
  • Which of the following choices are the characteristics of life
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!