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3 years ago

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.
Chemical reaction: C₆H₅NH₂(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

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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

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3 years ago

Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation isC7H6

prisoha [69]

Answer:

For a: The mass of acetic anhydride needed is 73.91 grams.

For b: The theoretical yield of aspirin is 130.43 grams.

Explanation:

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

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

For a:

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.

For b:

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.

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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

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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:

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