For the fuel cell described above in problem 2.14, assuming operation on pure hydrogen fuel, how much water would be produced during 24 hours of operation at P = 2 kW? (Recall: molar mass of water = 18 g/mol, density of water = 1 g/cm3.)
(a) 0.49 L
(b) 10.7 L
(c) 32.2 L
(d) 66.3 L

The average value of [Ca2+] and use to the Ksp of Ca(OH)2 is  1.14 x [tex]10^{-5}[/tex].

The dissolution reaction of calcium hydroxide in water can be represented as:

Ca(OH)2 (s) ⇌ Ca2+ (aq) + 2 OH- (aq)

The ICE table for the dissolution reaction is as follows:

Initial: Ca(OH)2 (s) -- --

Change: - +x +2x

Equilibrium: Ca(OH)2 (s) x 2x

Using the titration data, we can calculate the moles of H+ added to the solution:

Trial 1: 0.0109 L x 0.1045 M = 0.00114 moles H+

Trial 2: 0.01064 L x 0.1045 M = 0.00111 moles H+

Trial 1: [OH-] = 0.00114 moles / (0.025 L x 2) = 0.0228 M

Trial 2: [OH-] = 0.00111 moles / (0.025 L x 2) = 0.0222 M

Using the ICE table, we can calculate the concentration of Ca2+:

Trial 1: [Ca2+] = 2x = 2(0.0228 M) = 0.0456 M

Trial 2: [Ca2+] = 2x = 2(0.0222 M) = 0.0444 M

Finally, we can calculate the average value of [Ca2+] and use it to calculate the Ksp of Ca(OH)2:

[Ca2+]avg = (0.0456 M + 0.0444 M) / 2 = 0.0450 M

Ksp = [Ca2+][OH-]² = (0.0450 M)(0.0225 M)² = 1.14 x [tex]10^{-5}[/tex]

Ksp, or the solubility product constant, is a term used in chemistry to describe the equilibrium constant of a sparingly soluble salt in a solvent. When salt is added to a solvent, it may not completely dissolve due to its limited solubility. At this point, the salt particles in the solution start to interact with the solvent molecules, forming a saturated solution.

The Ksp is a measure of the concentration of ions in the saturated solution, which is in equilibrium with the undissolved salt. It is calculated by multiplying the concentrations of the dissociated ions raised by their stoichiometric coefficients in the balanced chemical equation for the dissolution reaction. Ksp values are unique to each sparingly soluble salt and depend on factors such as temperature, pressure, and the solvent used.

To learn more about Ksp visit here:

brainly.com/question/31384943

#SPJ4

The answers are 1. the value of ΔH° for the combustion of one mole of methane is -801 kJ/mol and 2. the value of ΔE° for the combustion of one mole of methane is also -801 kJ/mol.

For more such question on combustion

https://brainly.com/question/24113573

#SPJ11

In a many-electron atom, only the electrons at the outermost energy level will participate in covalent bonding.

The valence shell is the outermost energy level of an atom. It contains the electrons that are most likely to be involved in chemical interactions, such as covalent bonding. Covalent bonding occurs when two atoms share one or more electrons in order to achieve a more stable electron configuration. The electrons in the valence shell of each atom are the ones that are shared in this process. Therefore, only the electrons in the valence shell of a many-electron atom will participate in covalent bonding.

To learn more about covalent bonding click here https://brainly.com/question/14509196

#SPJ11

Answer:

Explanation:

it's B. 2 HCI: 1 CaCO3 :)

The specifics of when a month starts differ from calendar to calendar; some rely on new, entirety, or crescent moons, while others do complex computations.

In contrast with solar calendars, which annual cycles are only based on the solar year, a lunar calendar includes a calendar built on the monthly phases of the Moon's aspects (synodic months, lunations). The Islamic calendar is the most extensively used lunar calendar.

A lunisolar calendar, in which the lunar months come into alignment to the solar year by some process of intercalation, such as by inserting a leap month, is distinguished from a strictly lunar calendar. The specifics of when a month starts differ from calendar to calendar; some rely on new, entirety, or crescent moons, while others do complex computations.

To know more about lunar calendar, here:

https://brainly.com/question/30488813

#SPJ1

a) The frequency of ultraviolet light is 8.54 * 10^{15} Hz

b) The wavelength of ultraviolet light is 35 nm

To solve for the frequency of ultraviolet light, we can use the equation E = hf, where E is the energy of the photon, h is Planck's constant, and f is the frequency of the photon. Rearranging the equation, we get f = E/h. Plugging in the given values, we get

f = \frac{(5.6610-18 J)}{(6.62607015 * 10^{-34} J s)

f = 8.54 * 10^{15} Hz.
To solve for the wavelength of ultraviolet light, we can use the equation c = λf, where c is the speed of light, λ is the wavelength, and f is the frequency. Rearranging the equation, we get λ = \frac{c}{f}. Plugging in the given values and the speed of light (299,792,458 m/s), we get

λ = \frac{(299,792,458 m/s)}{(8.54 * 10^{15} Hz)

λ= 35 nm (nanometers).
In summary, the frequency of ultraviolet light with a photon energy of 5.6610-18 J is 8.54 * 1015 Hz, and the corresponding wavelength is 35 nm. Ultraviolet light has a shorter wavelength and higher frequency than visible light, making it more energetic and potentially harmful to living organisms.

learn more about Ultraviolet light refer: https://brainly.com/question/28883964

#SPJ11

To calculate the joules of heat energy required to raise the temperature of 15 grams of gold from 22°C to 85°C, you can use the formula: Q = mcΔT where Q is the heat energy in joules, m is the mass in grams, c is the specific heat, and ΔT is the change in temperature.

Given: m = 15 grams c = 0.129 J/(g x °C) Initial temperature = 22°C Final temperature = 85°C First, find the change in temperature (ΔT): ΔT = Final temperature - Initial temperature ΔT = 85°C - 22°C ΔT = 63°C Now, plug the values into the formula: Q = (15 g) x (0.129 J/(g x °C)) x (63°C) Q = 121.635 J Since the answer should be in whole joules, you can round it to the nearest whole number: Q ≈ 122 J None of the given options match the calculated answer. However, option A (121 J) is closest to the calculated value of 122 J, so it can be considered as the best available answer among the provided options.

Learn more about temperature here-

https://brainly.com/question/11640665

#SPJ11

The correct statement concerning galvanic (voltaic) cells and electrolytic cells is that external electric energy must be supplied to an electrolytic cell, while in a galvanic (voltaic) cell, the redox reaction is always spontaneous.

Galvanic cells produce electrical energy from a spontaneous redox reaction, where the anode undergoes oxidation and the cathode undergoes reduction. This flow of electrons generates an electrical current that can be used to power electronic devices. In contrast, electrolytic cells require an external source of electrical energy to drive a non-spontaneous redox reaction. The anode serves as the site of oxidation, and the cathode serves as the site of reduction. By supplying electrical energy, the reaction can proceed in the desired direction, producing a product that would not form spontaneously.
In summary, galvanic cells can serve as a source of electrical energy, while electrolytic cells require external electric energy to drive a non-spontaneous reaction. The cathode is the site of reduction in a galvanic (voltaic) cell, but the cathode is the site of oxidation in an electrolytic cell. Finally, in a galvanic (voltaic) cell, the redox reaction is always spontaneous, while in an electrolytic cell, an external energy source is required to drive the non-spontaneous reaction.

for more such questions on   spontaneous.

https://brainly.com/question/29315358

#SPJ11

The mass of 3.15 mol of AgNO₃ is 533.6 grams, the mass of 0.0901 mol of CaCl₂ is 10.02 grams, and the mass of 11.86 mol of H₂S is 404.5 grams.

To calculate the mass in grams of each of the given substances, we need to use the molar mass of each compound. The molar mass of AgNO₃ (silver nitrate) is 169.87 g/mol, the molar mass of CaCl₂ (calcium chloride) is 110.98 g/mol, and the molar mass of H₂S (hydrogen sulfide) is 34.08 g/mol.

To calculate the mass of 3.15 mol of AgNO₃, we can use the following formula:

mass = moles x molar mass
mass = 3.15 mol x 169.87 g/mol
mass = 533.6 g

Therefore, the mass of 3.15 mol of AgNO₃ is 533.6 grams.

Similarly, to calculate the mass of 0.0901 mol of CaCl₂, we can use the formula:

mass = moles x molar mass
mass = 0.0901 mol x 110.98 g/mol
mass = 10.02 g

Therefore, the mass of 0.0901 mol of CaCl₂ is 10.02 grams.

Finally, to calculate the mass of 11.86 mol of H₂S, we can use the formula:

mass = moles x molar mass
mass = 11.86 mol x 34.08 g/mol
mass = 404.5 g

Therefore, the mass of 11.86 mol of H₂S is 404.5 grams.

To know more about mass, refer to the link below:

https://brainly.com/question/14200145#

#SPJ11

The hydrogen ion concentration ([h]) for a 0.0473 m solution of Barium hydroxide, [tex]Ba(OH)2[/tex] assuming complete dissociation of the compound is 0.0946 mol/L.

The symbol [h] typically refers to the hydrogen ion concentration in a solution.

The balanced equation for the solution of barium hydroxide is

[tex]Ba(OH)_{2} (s)[/tex] → [tex]Ba_{2}[/tex](aq) + 2OH-(aq)

Here [tex]Ba(OH)_{2}[/tex] dissolves completely. The concentration of barium hydroxide and OH- will be equal to the concentration  [tex]Ba(OH)2[/tex] originally added to the solution

The OH- concentration will be calculated as:

[OH-] = 2 × 0.0473 mol/L

[OH-]= 0.0946 mol/L

[h] = [H+] = [OH-] = 0.0946 mol/L

Therefore, we can conclude that the hydrogen ion concentration ([h]) is 0.0946 mol/L.

To learn more about Barium hydroxide

https://brainly.com/question/31327057

#SPJ4

NH3 is commonly known as ammonia and H2O is commonly known as water. Molecular compounds are formed by the combination of two or more non-metal elements.

These compounds are also known as covalent compounds as they are held together by covalent bonds. Covalent bonds are formed by the sharing of electrons between two atoms. Molecular compounds are characterized by their low melting and boiling points and are generally poor conductors of electricity.
NH3, which is ammonia, is a colourless gas with a pungent odour. It is used in the production of fertilizers, cleaning agents, and as a refrigerant. NH3 is composed of one nitrogen atom and three hydrogen atoms. It is a basic compound and reacts with acids to form ammonium salts.
H2O, which is water, is a colourless, odourless, and tasteless liquid. It is essential for all forms of life on Earth and is the most common substance on Earth's surface. Water is composed of two hydrogen atoms and one oxygen atom. It is a polar compound, which means it has a positive and negative end. Water is a versatile solvent and is capable of dissolving many substances.
In conclusion, NH3 is commonly known as ammonia and H2O is commonly known as water. These molecular compounds have unique properties and are essential to life on Earth.

To learn more about molecular compounds, refer:-

https://brainly.com/question/30328923

#SPJ11

The number of electrons transferred in the balanced reaction NiSO₄(aq) + 2Cr(s) → Ni(s) + Cr₂(SO₄)₃(aq) + 3e⁻ are 3.

To balance the given redox reaction, we need to first identify the oxidation states of the elements in the reactants and products. In NiSO₄, the oxidation state of Ni is +2, while in Ni(s) it is 0. In Cr(s), the oxidation state of Cr is 0, while in Cr₂(SO₄)₃, it is +3.

We can balance the equation by adding electrons (e-) to one of the species. The oxidation half-reaction is,

Cr → Cr³⁺ + 3e⁻

The reduction half-reaction is,

Ni²⁺ + 2e⁻ → Ni

By multiplying the oxidation half-reaction by 2 and adding it to the reduction half-reaction, we get the balanced equation:

NiSO₄(aq) + 2Cr(s) → Ni(s) + Cr₂(SO₄)₃(aq) + 3e⁻

In this balanced equation, 3 moles of electrons are transferred.

To know more about balancing redox reaction, visit,

https://brainly.com/question/27907895

#SPJ4

Complete question - Consider the following unbalanced redox reaction,

NiSO₄(aq) + Cr(s) → Ni(s) + Cr₂(SO₄)₃(aq) how many moles of electrons are transferred in the balanced reaction?

Answer: CH4

Explanation: Methane

To create a concise informative plot for each of the terms listed, the following items are required: 1. Reaction, Chemicals or System Being Investigated:
Title: Give a descriptive title that clearly indicates the nature of the investigation.
Axes: Label the x-axis and y-axis with the appropriate variables that are being measured.
Data: Plot the data points on the graph.
Table with Headers Containing Units: Create a table that displays the data collected during the experiment, with headers containing units.
Name or Symbol of the Variable: Clearly identify the variables being measured, either by their name or symbol.

2. Special Conditions of the Experiment:
Title: Include the special conditions being tested in the title.
Axes: Label the x-axis and y-axis with the appropriate variables that are being measured.
Data: Plot the data points on the graph.
Table with Headers Containing Units: Create a table that displays the data collected during the experiment, with headers containing units.
Name or Symbol of the Variable: Clearly identify the variables being measured, either by their name or symbol.

3. Best Fit Line or Curve with an Equation:
Title: Give a descriptive title that clearly indicates the nature of the investigation.
Axes: Label the x-axis and y-axis with the appropriate variables that are being measured.
Data: Plot the data points on the graph.
Best Fit Line or Curve with an Equation: Draw the best fit line or curve through the data points and display the equation on the graph.
Units (if any): Include units on the axes and in the equation.
Name or Symbol of the Variable: Clearly identify the variables being measured, either by their name or symbol.

4. Units (if any):
Title: Give a descriptive title that clearly indicates the nature of the investigation.
Axes: Label the x-axis and y-axis with the appropriate variables that are being measured, including their units.
Data: Plot the data points on the graph.
Table with Headers Containing Units: Create a table that displays the data collected during the experiment, with headers containing units.
Name or Symbol of the Variable: Clearly identify the variables being measured, either by their name or symbol.

5. Table with Headers Containing Units:
Title: Give a descriptive title that clearly indicates the nature of the investigation.
Axes: Label the x-axis and y-axis with the appropriate variables that are being measured.
Table with Headers Containing Units: Create a table that displays the data collected during the experiment, with headers containing units.
Name or Symbol of the Variable: Clearly identify the variables being measured, either by their name or symbol.

To know more about chemical reaction, refer

https://brainly.com/question/25769000

#SPJ11

1. CO: 3 electron pairs are shared.
2. O₂: Two electron pairs are shared.
3. ClO: 1 electron pair is shared.
4. CN: Three electron pairs are shared.

Here's the information about the shared electron pairs (bonds) in each of the molecules and ions:

1. CO - Carbon Monoxide has a triple bond between C and O, which means 3 electron pairs are shared.
2. O₂ - Oxygen molecule has a double bond between the two O atoms, which means 2 electron pairs are shared.
3. ClO - Chlorine Monoxide has a single bond between Cl and O, which means 1 electron pair is shared.
4. CN - Cyanide ion has a triple bond between C and N, which means 3 electron pairs are shared.

For more such questions on Electron pairs.

https://brainly.com/question/18651326#

#SPJ11

The correct option is J, They are gaseous at room temperature and chemically stable" which correctly describes the properties of the elements in Group 18.

Room temperature is typically defined as the temperature range at which a substance or reaction is carried out under normal laboratory conditions, without the need for specialized equipment or procedures to control the temperature. Room temperature is usually considered to be around 20-25 degrees Celsius (68-77 degrees Fahrenheit), although this can vary slightly depending on the specific laboratory or experiment.

At room temperature, most common substances are in a stable, solid or liquid state, and many chemical reactions can take place at a reasonable rate without the need for additional heating or cooling. However, it is important to note that certain reactions or materials may require more precise temperature control in order to ensure accurate results or prevent safety hazards.

To learn more about Room temperature visit here:

brainly.com/question/8739174

#SPJ4

Answer:

D) Oxygen Gas

Explanation:

Early Earth's atmosphere lacked oxygen gas due to the lack of general vegetation on Earth (plants produce O2 gas as a byproduct of photosynthesis) and the large presence of volcanic gases, which are mostly made up of CO2.

Molecules are two or more atoms held together by chemical bonds. Therefore the correct option is option A.

A molecule is created when two or more atoms bind to one another. It doesn't matter whether the atoms are from the same element (like O2) or from different elements (like H2O, which has two hydrogen atoms and one oxygen atom). Covalent, ionic, or metallic chemical bonds can hold the atoms of a molecule together.

The smallest units of a compound that still have their chemical properties are called molecules. Chemical processes can separate them into individual atoms, but physical processes like heating or freezing cannot. Therefore the correct option is option A.

For such more question on Molecules:

https://brainly.com/question/475709

#SPJ11

When some of the NH4NO3 solid is spilled on the lab bench and not successfully added to the calorimeter, it will affect the final temperature of the water/solution in the calorimeter.

A calorimeter is a device used to measure the heat of a chemical reaction or physical change. In this case, the reaction between NH4NO3 and water is being measured.Since a smaller amount of NH4NO3 is added to the calorimeter, the reaction's heat production will be less than expected. As a result, the temperature change of the water/solution in the calorimeter will be smaller. This means that the final temperature of the water/solution will be higher than it would have been if the correct amount of NH4NO3 had been added.In summary, spilling some of the NH4NO3 solid on the lab bench and not adding it to the calorimeter will cause the final temperature of the water/solution in the calorimeter to be higher than expected, as less heat is produced by the reaction with a smaller amount of NH4NO3.

Learn more about calorimeter here

https://brainly.com/question/2963957

#SPJ11

Boric acid is a monoprotic and Lewis acid. B(OH)[tex]_3[/tex] + H[tex]_2[/tex]O ⇌ [BO(OH)[tex]_2[/tex]]− + H[tex]_3[/tex]O+ and HBO[tex]_2[/tex] + H[tex]_2[/tex]O ⇌ [BO[tex]_2[/tex]]− + H[tex]_3[/tex]O+ are the reactions for ionisation of boric acid.

In particular, orthoboric acid is a boron, oxygen, plus hydrogen chemical having the formula B(OH)3. Trihydroxidoboron, hydrogen orthoborate, and boracic acid are other names for it. It occurs naturally as the substance known as sassolite and is typically found as colourless crystals.

A white powder that dissolves in water. It is a weak acid that can react using alcohols to produce borate esters as well as a variety of borate anions and salts. Boric acid is a monoprotic and Lewis acid. B(OH)[tex]_3[/tex] + H[tex]_2[/tex]O ⇌ [BO(OH)[tex]_2[/tex]]− + H[tex]_3[/tex]O+ and HBO[tex]_2[/tex] + H[tex]_2[/tex]O ⇌ [BO[tex]_2[/tex]]− + H[tex]_3[/tex]O+ are the reactions for ionisation of boric acid.

To know more about Boric acid, here:

https://brainly.com/question/14879930

#SPJ1

An effective safety measure when running a new reaction is to start by b. Run the reaction on a small scale.

By conducting the experiment with smaller quantities of reactants, you can minimize potential hazards and more easily monitor the reaction. This allows you to observe any unexpected outcomes or side reactions that may occur.
Keeping the temperature low is another important safety measure. High temperatures can lead to increased reaction rates and the formation of more side products, making the reaction difficult to control. By maintaining a lower temperature, you can better manage the reaction and ensure a safer process.
Running the reaction for a short time is also a useful strategy. By limiting the reaction time, you can quickly identify any issues that may arise, such as excessive heat generation or unexpected byproducts. This enables you to address these issues promptly before they escalate.
While avoiding catalysts may seem like a safe choice, it is essential to understand that catalysts can improve the reaction's efficiency and selectivity. When used correctly, catalysts can make a reaction safer and more controlled. It is crucial to choose an appropriate catalyst and use it in the correct proportions to ensure a safe reaction.
In summary, when running a new reaction, it is essential to implement safety measures such as running the reaction on a small scale, maintaining a low temperature, and limiting the reaction time. Additionally, the proper use of catalysts can enhance reaction safety and control.

To learn more about new reaction, refer:-

https://brainly.com/question/19072147

#SPJ11

Answer:

NUCLEAR FISSION

Explanation:

According to Einstein's equation, E = mc2, where

m

is the mass and

c

is the speed of light states that mass can be converted to energy and vice-versa. In nuclear fission, the mass of reactants is more than mass of the products. The difference in mass is called the mass defect. This mass is converted into energy

Nuclear fission is only experimental however, nuclear fusion is not experimental.

Fission generates energy by breaking heavier atoms, such as uranium, into smaller atoms like iodine, cesium, strontium, xenon, and barium, to mention a few.

Fusion, on the other hand, is the joining of light atoms, such as two hydrogen isotopes.

Both are nuclear reactions that generate energy, but they are not the same. Fusion is the joining of two light nuclei to create a larger nucleus, whereas fission is the breaking of a heavy nucleus into two lighter ones.

Learn more about Nuclear fission and Fusion here:
https://brainly.com/question/3992688

#SPJ1

A chemical equation is balanced when E. the number of atoms of each element is the same in reactants and products because in a balanced chemical reaction the amount of reactants is equal to the amount of products.

A balanced chemical equation represents a chemical reaction with the same number of atoms of each element on both sides of the equation. In other words, the total mass and the number of atoms in the reactants are equal to those in the products.

The balance of the equation is achieved by adjusting the coefficients in front of the chemical formulas of the reactants and products to ensure that the same number of atoms of each element is present on both sides of the equation.  Hence, option E is correct.

Balancing the chemical equation is important as it helps to predict the amount of reactants and products that will be used and formed, respectively, and it also ensures that the reaction follows the law of conservation of mass.

To learn more about chemical equation, click here:

https://brainly.com/question/30087623

#SPJ11

The written formula for Manganese (IV) nitrate is Mn(NO₃)₄.

In this formula, Manganese (Mn) has a +4 charge (indicated by the Roman numeral IV) and Nitrate (NO₃) has a -1 charge.

To create a neutral compound, we need four nitrate ions to balance the +4 charge of Manganese.

Therefore, we write the formula as Mn(NO₃)₄.

Hence, The written formula for Manganese (IV) nitrate is Mn(NO₃)₄, which consists of one Manganese ion with a +4 charge and four nitrate ions, each with a -1 charge, to form a neutral compound.

learn more about Manganese click here:

https://brainly.com/question/28533522

#SPJ11

Mitochondria is a double membrane bound organelle which is found in most eukaryotic organisms. They are found inside the cytoplasm and essentially function as the cells digestive system. Here number 3 represents the mitochondria. The correct option is C.

Mitochondria popularly known as the power house of the cell play an important role in breaking down the nutrients and produce energy rich molecules for the cell. Its size ranges from 0.5 to 1.0 micrometer in diameter.

The mitochondria is a double membraned rod shaped structure which is found both in plants and animals. It comprises of an outer membrane, inner membrane and a gel material called matrix.

Thus the correct option is C.

To know more about mitochondria, visit;

https://brainly.com/question/29763308

#SPJ1

The hydrogen ions from the acid react with the hydroxide ions from the base to form water. This reaction is also known as an acid-base neutralization reaction. The resulting solution is neutral, meaning that it has a pH of 7. The correct option is C.

When an acid is neutralized by a base, the resulting solution contains water and a salt.

In a neutral solution, the concentration of hydrogen ions (H⁺) is equal to the concentration of hydroxide ions (OH⁻). This means that the answer is C - always equal to the concentration of hydroxide ions. The equation for this reaction is:

HA + BOH → H₂O + BA

In this equation, HA represents an acid, BOH represents a base, H₂O represents water, and BA represents a salt.

The pH of a solution can be determined by calculating the concentration of hydrogen ions. If the concentration of hydrogen ions is greater than the concentration of hydroxide ions, the solution is acidic and has a pH less than 7. If the concentration of hydroxide ions is greater than the concentration of hydrogen ions, the solution is basic and has a pH greater than 7. In a neutral solution, the concentration of hydrogen ions is equal to the concentration of hydroxide ions, resulting in a pH of 7.

To know more about neutralization reaction, refer to the link below:

https://brainly.com/question/28970253#

#SPJ11

Ionic bonds lead to the formation of crystal lattices, rather than separate, discrete molecules.

Positively charged cations and negatively charged anions are produced when electrons are transported from one atom to another in an ionic bond.

Then, these ions arrange themselves into a three-dimensional array to reduce the system's potential energy. A repeating unit cell can serve as a representation of the final structure, a crystal lattice.

Instead of distinct, discrete molecules, crystal lattices are formed as a result of ionic bonding.

Strong electrostatic interactions between the ions with opposing charges hold the lattice together. Ionic chemicals do not exist as isolated molecules since the lattice permeates the entire crystal.

For such more question on molecules:

https://brainly.com/question/475709

#SPJ11

The pH of the solution before the addition of any strong acid is 12 and the primary species left in the solution are mixture of the weak base and conjugate acid.

a) Before any strong acid has been added, the solution contains only the weak base B. To find the pH of the solution, we can use the expression for the base dissociation constant:

Kb = [BH⁺][OH⁻]/[B]

At equilibrium, we can assume that [OH⁻] ≈ [BH⁺], since the base is weak and only partially dissociates. Therefore:

Kb = [OH⁻]²/[B]

[OH⁻]² = Kb[B]

[OH⁻] = √(Kb[B]) = √(7.5×10⁻⁶ mol/L × 0.318 L) ≈ 5.4×10⁻³ mol/L

Since Kw = [H⁺][OH⁻], we can find the [H⁺] concentration:

Kw = [H⁺][OH⁻]

[H⁺] = Kw/[OH⁻]

= 1.0×10⁻¹⁴ mol²/L² ÷ 5.4×10⁻³ mol/L

≈ 1.9×10⁻¹² mol/L

The pH of the solution is then:

pH = -log[H⁺] ≈ 12

The pH of the solution is therefore roughly 12 prior to the addition of any strong acids.

b) After adding 30.0 mL of HNO₃, we have added:

n(HNO₃) = C(V) = 0.340 mol/L × 0.0300 L = 0.0102 mol

Since the base is weak, we can assume that all of the added HNO₃ reacts with the base, and that the solution is still basic. The base will be partially neutralized to form the conjugate acid BH⁺, which is also weak. The primary species left in the solution will be a mixture of the weak base B, its conjugate acid BH⁺, and any excess HNO₃ that has not reacted with the base.

To know more about pH value, visit,

https://brainly.com/question/26424076

#SPJ4

Using crystal field theory, the number of unpaired electrons in [Mn(NH₃)₆]²⁺ is three.

Using crystal field theory, we can determine the number of unpaired electrons in the complex ion [Mn(NH₃)₆]²⁺+ as follows:

The complex ion consists of a central Mn²⁺ ion, which is surrounded by six NH₃ ligands. Mn²⁺ has an electron configuration of [Ar] 3d⁵, meaning it has five electrons in its d orbitals. The NH₃ ligands are considered weak field ligands, meaning they cause a small energy difference between the d orbitals.

In weak field complexes, the electrons preferentially occupy the lower energy orbitals in a way that maximizes the number of unpaired electrons (Hund's rule). In an octahedral complex, such as [Mn(NH₃)₆]²⁺, the d orbitals are split into two groups: the t²g orbitals (dxy, dxz, dyz) and the eg orbitals (dz², dx²-y²). The t²g orbitals are lower in energy than the eg orbitals.

As there are five d electrons in Mn²⁺, they will first fill the t²g orbitals, with one electron each (following Hund's rule). This results in three unpaired electrons in the [Mn(NH₃)₆]²⁺ complex ion.

To know more about crystal field theory, refer to the link below:

https://brainly.com/question/29389010#

#SPJ11