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Dmitrij [34]
3 years ago
14

What is the ph of a 0.45 m solution of aniline (c6h5nh2)? (pkb  9.40)?

Chemistry
1 answer:
mote1985 [20]3 years ago
7 0

Answer is: pH of aniline is 9.13.<span>
Chemical reaction: C</span>₆H₅NH₂(aq)+ H₂O(l) ⇌ C₆H₅NH₃⁺(aq) + OH⁻(aq).

pKb(C₆H₅NH₂) = 9.40.

Kb(C₆H₅NH₂) = 10∧(-9.4) = 4·10⁻¹⁰.

c₀(C₆H₅NH₂) = 0.45 M.

c(C₆H₅NH₃⁺) = c(OH⁻) = x.

c(C₆H₅NH₂) = 0.45 M - x.

Kb = c(C₆H₅NH₃⁺) · c(OH⁻) / c(C₆H₅NH₂).

4·10⁻¹⁰ = x² /  (0.45 M - x). 

Solve quadratic equation: x = c(OH⁻) = 0.0000134 M.

pOH = -log(0.0000134 M.) = 4.87.

pH = 14 - 4.87 = 9.13.

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"the osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant
ASHA 777 [7]

Answer: -

The concentration is 0.91 mol/ L

Explanation: -

The osmotic pressure = 23 atm

Absolute temperature = 309 K

Universal gas constant = 0.08206 L atm mol⁻¹ K⁻¹

We know the formula

Osmotic pressure = molar concentration x universal gas constant x absolute temperature

Plugging in the values

23 atm = molar concentration x 0.08206 L atm mol⁻¹ K⁻¹ x 309 K

Molar concentration = \frac{23}{0.08206 x 309} mol/ L

                                  = 0.91 mol / L

8 0
3 years ago
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What is the density of a rectangle solid with dimensions
Hunter-Best [27]

Answer:

5625000gm/cm^3

Explanation:

volume=w*h*l=25*15*5=1875cm^3

density=mass*volume

=1875*3000

=5625000gm/cm^3

8 0
3 years ago
Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation isC7H6
prisoha [69]

<u>Answer:</u>

<u>For a:</u> The mass of acetic anhydride needed is 73.91 grams.

<u>For b:</u> The theoretical yield of aspirin is 130.43 grams.

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}   .....(1)

  • <u>For a:</u>

Given mass of salicylic acid = 1.00\times 10^2g=100g

Molar mass of salicylic acid = 138.121 g/mol

Putting values in equation 1, we get:

\text{Moles of salicylic acid}=\frac{100g}{138.121g/mol}=0.724mol

For the given chemical reaction:

C_7H_6O_3+C_4H_6O_3\rightarrow C_9H_8O_4+CH_3COOH

By stoichiometry of the reaction:

1 mole of salicylic acid reacts with 1 mole of acetic anhydride.

So, 0.724 moles of salicylic acid will react with = \frac{1}{1}\times 0.724=0.724mol of acetic anhydride.

Now, to calculate the mass of acetic anhydride, we use equation 1:

Moles of acetic anhydride = 0.724 moles

Molar mass of acetic anhydride = 102.09 g/mol

Putting values in equation 1, we get:

0.724mol=\frac{\text{Mass of acetic anhydride}}{102.09g/mol}\\\\\text{Mass of acetic anhydride}=73.91g

Hence, the mass of acetic anhydride needed is 73.91 grams.

  • <u>For b:</u>

By stoichiometry of the reaction:

1 mole of salicylic acid is producing 1 mole of aspirin.

So, 0.724 moles of salicylic acid will produce = \frac{1}{1}\times 0.724=0.724mol of aspirin.

Now, to calculate the mass of aspirin, we use equation 1:

Moles of aspirin = 0.724 moles

Molar mass of aspirin = 180.158 g/mol

Putting values in equation 1, we get:

0.724mol=\frac{\text{Mass of aspirin}}{180.158g/mol}\\\\\text{Mass of aspirin}=130.43g

Hence, the theoretical yield of aspirin is 130.43 grams.

4 0
3 years ago
The elements present in a group of periodic table have
MissTica

Answer:

group 1 elements(hydrogen,sodium,etc)

Explanation:

bexause if noticed all the element in the same group have the same eletron in thr outer most shell for example the group 1 elements are said to have 1 outermost elect ron which make them react so the same

7 0
3 years ago
Why is it dangerous to react sodium and potassium with dulute sulphuric acid?​
spin [16.1K]

Answer:

Because sodium and potassium are very reactive metals so they react explosively with HCL and H2SO4 evolving a large amount of heat.

Explanation:

5 0
3 years ago
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