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
geniusboy [140]
3 years ago
12

The benzoate ion, c6h5coo− is a weak base with kb=1.6×10−10. how many moles of sodium benzoate are present in 0.50 l of a soluti

on of nac6h5coo if the ph is 9.04?
Chemistry
2 answers:
lyudmila [28]3 years ago
8 0

NaC6H5COO \rightarrow Na{^{+}} + C6H5COO^{-}

Here the base is a benzoate ion, which is a weak base and reacts with water.

C6H5COO^{-}(aq) + H2O (l)\leftrightarrow C6H5COOH(aq)+ OH^{-}(aq)

The equation indicates that for every mole of OH- that is produced , there is one mole of C6H5COOH produced.

Therefore [OH-] = [C6H5COOH]

In the question value of PH is given and by using pH we can calculate pOH and then using pOH we can calculate [OH-]

pOH = 14 - pH

pH given = 9.04

pOH = 14-9.04 = 4.96

pOH = -log[OH-] or [OH^{-}] = 10^{^{-pOH}}

[OH^{-}] = 10^{^{-4.96}}

[OH^{-}] = 1.1\times 10^{-5}

The base dissociation equation kb = \frac{Product}{Reactant}

kb =\frac{[C6H5COOH][OH^{-}]}{[C6H5COO^{-}]}

H2O(l) is not included in the 'kb' equation because 'solid' and 'liquid' are taken as unity that is 1.

Value of Kb is given = 1.6\times 10^{-10}

And value of [OH-] we have calculated as 1.1\times 10^{-5} and value of C6H5COOH is equal to OH-

Now putting the values in the 'kb' equation we can find the concentration of C6H5COO-

kb =\frac{[C6H5COOH][OH^{-}]}{[C6H5COO^{-}]}

1.6\times 10^{-10} = \frac{[1.1\times 10^{-5}][1.1\times 10^{-5}]}{[C6H5COO^{-}]}

[C6H5COO^{-}] = \frac{[1.1\times 10^{-5}][1.1\times 10^{-5}]}{1.6\times 10^{-10}}

[C6H5COO^{-}] = 0.76 M or 0.76\frac{mol}{L}

So, Concentration of NaC6H5COO would also be 0.76 M and volume is given to us 0.50 L , now moles can we calculated as : Moles = M X L

Moles of NaC6H5COO would be = 0.76(\frac{mol}{L}) \times (0.50L)

Moles of NaC6H5COO (sodium benzoate) = 0.38 mol

mr_godi [17]3 years ago
5 0

Answer : The number of moles of sodium benzoate is, 0.375 moles

Solution :

First we have to calculate the pOH.

pOH=14-pH=14-9.04=4.96

Now we have to calculate the concentration of [tex[OH^-[/tex] ions.

pOH=-\log [OH^-]

4.96=-\log [OH^-]

[OH^-]=1.096\times 10^{-5}

The equilibrium reaction for dissociation of weak base is,

                   C_6H_5COO^-+H_2O\rightleftharpoons OH^-+C_6H_5COOH

initially conc.         c                              0         0

At eqm.              c(1-\alpha)                      c\alpha        c\alpha

The expression for dissociation constant is,

k_b=\frac{c\alpha\times c\alpha}{c(1-\alpha)}

when \alpha is very very small the, the expression will be,

k_b=\frac{c^2\alpha^2}{c}=c\alpha^2\\\\\alpha=\sqrt{\frac{k_b}{c}}

And,

[OH^-]=c\alpha

Thus the expression will be,

[OH^-]=\sqrt{k_b\times c}

Now put all the given values in this expression, we get

1.096\times 10^{-5}=\sqrt{(1.6\times 10^{-10})\times c}

c=0.75M

Now we have to calculate the moles of sodium benzoate.

Moles=concentration\times volume=0.75M\times 0.5L=0.375moles

Therefore, the number of moles of sodium benzoate is, 0.375 moles

You might be interested in
If 75 grams of oxygen react, how many grams of aluminum are required?
german

Answer:

84.24 g

Explanation:

Given data:

Mass of oxygen = 75 g

Mass of Al required to react = ?

Solution:

Chemical equation:

4Al + 3O₂     →   2Al₂O₃

Number of moles of oxygen:

Number of moles = mass/ molar mass

Number of moles = 75 g/ 32 g/mol

Number of moles = 2.34 mol

Now we will compare the moles of oxygen with Al.

                          O₂         :          Al

                           3          :             4

                        2.34        :         4/3×2.34 = 3.12 mol

Mass of Al required:

Mass = number of moles × molar mass

Mass = 3.12 mol × 27 g/mol

Mass = 84.24 g

5 0
3 years ago
What is the pOH of a solution of HNO3 that has [OH-] = 9.50 10-9 M?
bekas [8.4K]

Answer:

The pOH of HNO₃ solution that ha OH⁻ concentration 9.50 ×10⁻⁹M is 8.

Explanation:

Given data:

[OH⁻] = 9.50 ×10⁻⁹M

pOH = ?

Solution:

pOH = -log[OH⁻]

Now we will put the value of OH⁻ concentration.

pOH = -log[9.50 ×10⁻⁹M]

pOH = 8

Thus the pOH of HNO₃ solution that ha OH⁻ concentration 9.50 ×10⁻⁹M is 8.

6 0
3 years ago
Read 2 more answers
Which of the following is a chemical property of water? It ___________.
lbvjy [14]
The answer is A beautiful
4 0
3 years ago
Since the new oceanic crust is created at the mid-ocean ridges, then the Earth is getting bigger.
Svet_ta [14]

Answer:

False

Explanation:

It is true that new crust is being created at the mid-oceanic ridges, but this does not make the Earth any bigger despite the the growth of oceanic crusts in these regions.

The reason that Earth does not get bigger is because the same plates that are being created at the divergent plate boundaries are recycled into the mantle at the subduction zones. Because of this, the surface area of the Earth remains the same.

7 0
3 years ago
An 80 kg long jumper in flight accelerates at a rate of 10 m/s^2. What is the force of the long jumper
Katarina [22]

Answer:

F = 800 N

Explanation:

Given data:

Mass = 80 Kg

Acceleration = 10 m/s²

Force = ?

Solution:

Formula:

<em>F = m × a </em>

F = force

m = mass

a = acceleration

Now we will put the values in formula:

<em>F = m × a </em>

F = 80 kg <em>× </em>10 m/s²

F = 800 kg.m/s²

kg.m/s² = N

F = 800 N

6 0
3 years ago
Other questions:
  • O, li, c which electrons experience the greatest effective nuclear charge? express your answer as a chemical formula.
    10·1 answer
  • In your double replacement reaction, the more reactive metal "pushed" the other one out of its place. Without using the Internet
    12·1 answer
  • How many moles of hydrogen gas would be needed to react with excess carbon dioxide to produce 99.1 moles of water vapor?
    14·1 answer
  • How many minutes will it take for a car traveling 74 miles per hour to cover 6.50 kilometers?
    13·1 answer
  • Help me!!! :(<br> Plissss!!!!!
    11·1 answer
  • How are you able to light a bunsen burner​
    10·1 answer
  • How do you describe the particles in a liquid? ​
    9·2 answers
  • A gene is being copied to be passed from a parent to an offspring. While being copied from the parent, a
    12·1 answer
  • 1a) Why do we study gases since reformation​
    8·1 answer
  • (a) Is a weak Brønsted-Lowry base necessarily a weak Lewis base? Explain with an example.
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!