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3 years ago

14. What is the pH of a 0.24 M solution of sodium propionate, NaC3H502, at 25°C? (For

Chemistry

1 answer:

Murrr4er [49]3 years ago

5 0

Answer:

9.1

Explanation:

Step 1: Calculate the basic dissociation constant of propionate ion (Kb)

Sodium propionate is a strong electrolyte that dissociates according to the following equation.

NaC₃H₅O₂ ⇒ Na⁺ + C₃H₅O₂⁻

Propionate is the conjugate base of propionic acid according to the following equation.

C₃H₅O₂⁻ + H₂O ⇄ HC₃H₅O₂ + OH⁻

We can calculate Kb for propionate using the following expression.

Ka × Kb = Kw

Kb = Kw/Ka = 1.0 × 10⁻¹⁴/1.3 × 10⁻⁵ = 7.7 × 10⁻¹⁰

Step 2: Calculate the concentration of OH⁻

The concentration of the base (Cb) is 0.24 M. We can calculate [OH⁻] using the following expression.

[OH⁻] = √(Kb × Cb) = √(7.7 × 10⁻¹⁰ × 0.24) = 1.4 × 10⁻⁵ M

Step 3: Calculate the concentration of H⁺

We will use the following expression.

Kw = [H⁺] × [OH⁻]

[H⁺] = Kw/[OH⁻] = 1.0 × 10⁻¹⁴/1.4 × 10⁻⁵ = 7.1 × 10⁻¹⁰ M

Step 4: Calculate the pH of the solution

We will use the definition of pH.

pH = -log [H⁺] = -log 7.1 × 10⁻¹⁰ = 9.1

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"an acid is a substance that forms hydrogen ions when dissolved in water." this is an example of —

LenaWriter [7]

Answer is: this is an example of an Arrhenius acid.

An Arrhenius acid is a substance that dissociates in water to form hydrogen ions or protons (H⁺).

For example hydrochloric acid: HCl(aq) → H⁺(aq) + Cl⁻(aq).

An Arrhenius base is a substance that dissociates in water to form hydroxide ions (OH⁻).
In this example lithium hydroxide is an Arrhenius base:

LiOH(aq) → Li⁺(aq) + OH⁻(aq).

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3 years ago

What is the charge on the phosphorus atom in the polyatomic ion: PO4-3

oee [108]

Explanation:

The given radical is PO₄³⁻

To solve this problem, we need to understand what oxidation number entails.

The extent of the oxidation of each atom is expressed by the oxidation number.

Here are some rules for assigning them:

Elements in an uncombined state or elements that combines with one another, their oxidation number is zero.
The charge on an ion is its oxidation number
In an neutral compound, algebraic sum of all the oxidation numbers of all atoms is zero.
In a radical, the algebraic sum of all the oxidation numbers of the ions is equal to the charge on them.

Oxygen is known to have an oxidation number of -2;

PO₄³⁻

P + 4(-2) = -3

P -8 = -3

P = -3 + 8 = +5

The charge on phosphorus is +5

learn more:

Oxidation number brainly.com/question/2086855

#learnwithbrainly

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3 years ago

A substance with a pH of 4.0?

IrinaVladis [17]

Tomato juice or acid rain

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3 years ago

Read 2 more answers

which are correct formulas for ionic compounds? for those that are not correct, give the correct formula and justify your answer

skelet666 [1.2K]

Answer:

Ionic compounds have a metal and nonmetal.

Ionic compounds are made up of ions.

Explanation:

You did not provide any formulas for me to correct, but:

ionic compounds tend to have metals and nonmetals. (EX: NaCl)You can look at the periodic table to see which elements are metals and which are not.
ionic compounds are made up of ions. Ions are elements that have a charge (Like $Cu^{2+}$ or $O^{-}$ ). To have a correct ionic compound, make sure that the ions inside of it "cancel" each other out.

EX: Na has a +1 charge. Cl has a -1 charge. When they are paired up, they successfully cancel each other out (become neutral) and become the ionic compound NaCl.

The chart below shows you the charge of each element. Make sure the charge of the elements in an ionic compound "cancel" each other out.

The very last chart shows the metals and nonmetals

Chart 1:found in https://chem.libretexts.org/Courses/Oregon_Tech_PortlandMetro_Campus/OT_-_PDX_-_Metro%3A_General_Chemistry_I/03%3A_Nuclei_Ions_and_the_Periodic_Table/3.03%3A_Predicting_Charges_of_Ions

Chart 2: found in https://sciencenotes.org/metals-metalloids-nonmetals/

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2 years ago

1. Which of the following statements about mechanical waves is true?

Anna [14]

1. The answer is "a".

Mechanical waves require a medium to travel. If there is no medium, the mechanical wave doesn't travel. Since, they are waves; they have a wavelength, frequency, speed and also amplitude. The speed depends on the medium and type of the wave. An example for the mechanical waves is sound wave.

2. E = hf, where E is energy, h is plank constant and f is the frequency. Hence, if the frequency is high, then the energy is high.

v = fλ , where v is the speed, f is the frequency and λ is the wavelength. If the frequency is high, then the wavelength is low.

According to the given choices, gamma rays have the shortest wavelength and highest energy on electromagnetic spectrum.

3. The wavelength of X-rays are smaller the wavelength of infrared.

According to the v=fλ, lower the wavelength, then higher the frequency. According to the E = hf, if the frequency is high, then the energy is also high.

Hence, the correct answer is "d"

4. In a longitudinal wave (compression wave) the particles of a matter move parallel.

There are two types of waves according to the particle movement. They are transverse waves and longitudinal waves. In transverse waves, the particles of the medium move perpendicular to the direction of the wave and longitudinal waves have parallel movement of particles to the direction of wave.

5. In regard to spend of sound, sound travels slowest in gases.

Solids have the highest speed of sound while gases have the lowest. This is because of the particle arrangement of each phase. Solid phase has very tightly packed particle arrangement and due to that the transfer of sound wave in easy than in gases.

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3 years ago