All categories

3 years ago

What is the ph of a 4.8 m pyridine solution that has kb = 1.9 × 10-9? the equation for the dissociation of pyridine is?

Chemistry

2 answers:

Arte-miy333 [17]3 years ago

7 0

C5H5N(aq)+H2)⇄C5H5NH+(aq)+OH-(aq)

Eddi Din [679]3 years ago

4 0

Answer: 9.98

Explanation:

1) The equation for the dissociation of pyridine is:

C₅H₅N₅(aq )+ H₂O(l) ⇄ C₅H₅NH⁺(aq) + OH⁻(aq)

2) Kb equation:

Kb = [C₅H₅NH⁺(aq)] [OH⁻(aq)] / [C₅H₅N₅(aq )]

Where:

[C₅H₅NH⁺(aq)] = [OH⁻(aq)] ← from the equilibrium reaction

[C₅H₅N₅(aq )] = 4.8 M ← from the statement

⇒ 1.9 × 10 ⁻⁹ = x² / 4.8 ⇒ x² = 9.12 × 10⁻⁹

⇒ x = 9.55 × 10⁻⁵ = [OH⁻(aq)]

3) pOH

pOH = - log [OH⁻(aq)] = 4.02

4) pOH + pH = 14

⇒ pH = 14 - 4.02 = 9.98

You might be interested in

Aluminum oxide (Al2O3) is a widely used industrial abrasive (known as emery or corundum), for which the specific application dep

ivanzaharov [21]

Answer:

On the Moh's scale of hardness, aluminum oxide is positioned just below to diamond due to which it is considered as one of the hardest known compounds. This also shows that the compound exhibit an enormous amount of lattice energy, as to transform the oxide into its constituent ions, the energy is required to overcome.

Based on the chemical formula of the compound, that is, Al2O3, it is shown that the ions of Al3+ and O2- are kept close due to the activity of the strong electrostatic ionic bonds. The electrostatic forces and the ionic bonding between the ions are extremely robust due to the presence of the ions high charge density. Therefore, to dissociate the bonds, an enormous amount of energy is needed, and at the same time, a high amount of lattice energy is present.

7 0

3 years ago

Which of the following is NOT an example of a chemical change?

Katyanochek1 [597]

Answer:

hi there !!

B) Water evaporates into steam.

this is correct because only physical state changes, steam can be cooled down to get water again.

4 0

3 years ago

Read 2 more answers

Problem PageQuestion The airbags that protect people in car crashes are inflated by the extremely rapid decomposition of sodium

Shalnov [3]

Answer:

1. 2NaN₃(s) → 2Na(s) + 3N₂(g)

2. 14.5 g NaN₃

Explanation:

The answer is incomplete, as it is missing the required values to solve the problem. An internet search shows me these values for this question. Keep in mind that if your values are different your result will be different as well, but the solving methodology won't change.

" The airbags that protect people in car crashes are inflated by the extremely rapid decomposition of sodium azide, which produces large volumes of nitrogen gas. 1. Write a balanced chemical equation, including physical state symbols, for the decomposition of solid sodium azide (NaN₃) into solid sodium and gaseous dinitrogen. 2. Suppose 71.0 L of dinitrogen gas are produced by this reaction, at a temperature of 16.0 °C and pressure of exactly 1 atm. Calculate the mass of sodium azide that must have reacted. Round your answer to 3 significant digits. "

1. The reaction that takes place is:

2NaN₃(s) → 2Na(s) + 3N₂(g)

2. We use PV=nRT to calculate the moles of N₂ that were produced.

P = 1 atm

V = 71.0 L

n = ?

T = 16.0 °C ⇒ 16.0 + 273.16 = 289.16 K

1 atm * 71.0 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 289.16 K

n = 0.334 mol

Now we convert N₂ moles to NaN₃ moles:

0.334 mol N₂ * $\frac{2molNaN_{3}}{3molN_2}$ = 0.223 mol NaN₃

Finally we convert NaN₃ moles to grams, using its molar mass:

0.223 mol NaN₃ * 65 g/mol = 14.5 g NaN₃

6 0

3 years ago

Enter the appropriate symbol for an isotope of phosphorus-32 corresponding to the isotope notation AZX. Express your answer as a

Lelechka [254]

Answer:

$^{32}_{15}P$

Explanation:

Atomic number : It is defined as the number of electrons or number of protons present in a neutral atom.

However, when we talk about the atomic number of the ion, it is not equal to the number of electrons as electron can be gained or loosed.

This is why, more appropriately, the number of the protons which are present in the nucleus of the atom is called the atomic number.

Thus, atomic number of phosphorus = 15

Mass number is the number of the entities present in the nucleus which is the equal to the sum of the number of protons and electrons.

Given, Mass number = 32

Thus, the symbol of the isotope is:-

$^{32}_{15}P$

8 0

3 years ago

A major component of gasoline is octane (C8H18). When liquid octane is burned in air it reacts with oxygen gas to produce carbon

Paraphin [41]

Answer:

The answer to your question is 0.4 moles of Oxygen

Explanation:

Data

Octane (C₈H₈)

Oxygen (O₂)

Carbon dioxide (CO₂)

Water (H₂O)

moles of water = ?

moles of Oxygen = 1

Balanced chemical reaction

C₈H₈ +10O₂ ⇒ 8CO₂ + 4H₂O

Reactant Element Products

8 C 8

8 H 8

20 O 20

Use proportions to solve this problem

10 moles of Oxygen ----------------- 4 moles of water

1 mol of Oxygen ------------------ x

x = (4 x 1) / 10

x = 4 / 10

x = 0.4 moles of water

7 0

3 years ago