What is the approximate
Hrxn for the hydrogen combustion reaction given the following bond energies?

O-H 470 kJ/mole, H - H 430 kJ/mole, O=O 500 kJ/mole. 2H2(g) + O2(g) --> 2H2O(g)

The enthalpy of the reactions include:

Using the heat of formation values listed below:

ΔHf°(Si) = 0 kJ/mol

ΔHf°(SiF₄) = -1613 kJ/mol

ΔHf°(F₂) = 0 kJ/mol

ΔHf°(H₂O) = -286 kJ/mol

ΔHf°(SO) = 248 kJ/mol

ΔHf°(H₂SO₄) = -814 kJ/mol

ΔHf°(KOH) = -424 kJ/mol

ΔHf°(K₂O₂) = -496 kJ/mol

ΔHf°(O₂) = 0 kJ/mol

ΔHf°(Fe₃O₄) = -1118 kJ/mol

ΔHf°(HCl) = -92 kJ/mol

ΔHf°(FeCl₂) = -341 kJ/mol

ΔHf°(FeCl₃) = -399 kJ/mol

The enthalpy of each reaction is:

(a) ΔH°rxn = [ΔHf°(Si) + 2ΔHf°(F₂)] - ΔHf°(SiF₄)

ΔH°rxn = [0 + 2(0)] - (-1613) kJ/mol

ΔH°rxn = 1613 kJ/mol

(b) ΔH°rxn = [ΔHf°(Si) + 2ΔHf°(F₂)] - ΔHf°(SiF₄)

ΔH°rxn = [0 + 2(0)] - (-1613) kJ/mol

ΔH°rxn = 1613 kJ/mol

(c) ΔH°rxn = [ΔHf°(H₂SO₄)] - [ΔHf°(SO) + ΔHf°(H₂O)]

ΔH°rxn = (-814) - [248 + (-286)] kJ/mol

ΔH°rxn = -276 kJ/mol

(d) ΔH°rxn = [6ΔHf°(KOH) + ΔHf°(O₂)] - [3ΔHf°(K₂O₂) + 3ΔHf°(H₂O)]

ΔH°rxn = [6(-424) + 0] - [3(-496) + 3(-286)] kJ/mol

ΔH°rxn = -1296 kJ/mol

(e) ΔH°rxn = [2ΔHf°(FeCl3) + ΔHf°(FeCl2) + 4ΔHf°(H₋O)] - [ΔHf°(Fe₃O₄) + 8ΔHf°(HCl)]

ΔH°rxn = [2(-399) + (-341) + 4(-286)] - [(-1118) + 8(-92)] kJ/mol

ΔH°rxn = -203 kJ/mol

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The body is capable of producing all of the amino acids it need, but it must have enough energy to do so. False

The body is capable of producing some of the amino acids it needs, but there are nine essential amino acids that it cannot make and must be obtained from the diet. Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine are among the necessary amino acids.

The body also requires energy to synthesize non-essential amino acids, and if there is insufficient energy, the body may not be able to produce enough of these amino acids. Therefore, both dietary intake and energy availability are important for optimal amino acid production and overall health.

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The statement "The body is capable of manufacturing all of the amino acids it needs but it must have sufficient energy to be able to do so. " is False.

The body is capable of producing some of the amino acids it needs, but there are nine essential amino acids that it cannot make and must be obtained from the diet. These essential amino acids include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

The body also requires energy to synthesize non-essential amino acids, and if there is insufficient energy, the body may not be able to produce enough of these amino acids. Therefore, both dietary intake and energy availability are important for optimal amino acid production and overall health.

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Answer:

We can use the ideal gas law to solve for the number of moles of gas:

PV = nRT

where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is temperature in Kelvin.

Plugging in the given values:

(1.35 atm)(25 L) = n(0.0821 L·atm/mol·K)(300 K)

n = (1.35 atm)(25 L) / (0.0821 L·atm/mol·K)(300 K)

n = 1.29 mol

Therefore, there are 1.29 moles of gas in the container.

The molality of concentrated hydrochloric corrosive is around 163.8 mol/kg. 

To discover the molality of hydrochloric corrosive, we ought to know the mass of HCl in 1 kg of the dissolvable (water).

Able to utilize the thickness of the arrangement and the molarity of the HCl to discover the mass of HCl in a given volume of the arrangement, and after that utilize the molar mass of HCl to change over mass to moles. At last, we will utilize the mass of water to calculate the molality of the arrangement.

The molar mass of HCl is around 36.5 g/mol.

To begin with, we ought to calculate the mass of HCl in 1 L (1000 mL) of the arrangement:

Mass of HCl in 1 L of arrangement = (thickness of arrangement) x (volume of solution) x (molarity of HCl) x (molar mass of HCl)

Mass of HCl in 1 L of arrangement = (1.18 g/mL) x (1000 mL) x (12.0 mol/L) x (36.5 g/mol) = 5.142 kg

Following, we have to calculate the mass of water within the arrangement:

Mass of water in 1 L of arrangement = (thickness of arrangement) x (volume of arrangement) - (mass of HCl in 1 L of arrangement)

Mass of water in 1 L of arrangement = (1.18 g/mL) x (1000 mL) - (5.142 kg) = 858 g

Presently able to calculate the molality of the arrangement:

Molality of HCl arrangement = (moles of solute) / (mass of dissolvable in kg)

MoL of solute (HCl) in 1 L of arrangement = (mass of HCl in 1 L of arrangement) / (molar mass of HCl) = 5.142 kg / 36.5 g/mol = 140.6 mol

Mass of dissolvable (water) in 1 L of arrangement = 858 g / 1000 g/kg = 0.858 kg

Molality of HCl arrangement = 140.6 mol / 0.858 kg = 163.8 mol/kg

Hence, the molality of concentrated hydrochloric corrosive is around 163.8 mol/kg. 

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Answer: exothermic reaction

Explanation: To create more heat, shift to the product side with the exothermic reaction. An exothermic reaction produces heat. The equation is:

N2(g) + 3H2(g) <-> 2NH3(g) + heat. It's exothermic because heat is a product.

The sigma bond between b and f in tetrafluoroborate ion, bf4-, is formed by the overlap of the atomic orbitals of boron and fluorine. Specifically, each of which contributes one p orbital to form a sp3-p sigma bond.

In the tetrafluoroborate ion (BF4-), the bond between boron (B) and fluorine (F) is a sigma (σ) bond. The σ bond is formed by the overlap of atomic or hybrid orbitals.Boron in BF4- is sp3 hybridized, which means that it has four hybrid orbitals that are involved in bonding. Three of these hybrid orbitals are involved in bonding with three of the fluorine atoms, while the fourth hybrid orbital is used to form the σ bond with the fourth fluorine atom.Fluorine is a halogen and has the electron configuration of 1s2 2s2 2p5. In BF4-, each of the fluorine atoms is also involved in the formation of the σ bond with boron. Fluorine has three unpaired electrons in its 2p orbitals that can form a σ bond by overlapping with the sp3 hybrid orbital of boron.Therefore, the σ bond between boron and fluorine in BF4- is formed by the overlap of the sp3 hybrid orbital of boron and the 2p orbital of the fluorine atom.

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The answer is (C) HS.

Each of the other options can donate a proton (act as a Brönsted acid) in certain conditions and accept a proton (act as a Brönsted base) in other conditions. However, HS is only capable of acting as a Brönsted base and accepting a proton, but it cannot donate a proton and act as a Brönsted acid.

Out of the given options, the one that cannot act as both an acid and a base is (C) HS. This is because HS can only act as a brönsted acid by donating a proton to a brönsted base, but it cannot act as a brönsted base by accepting a proton from a brönsted acid. This is because it lacks a lone pair of electrons on the sulfur atom, which is necessary for accepting a proton.

On the other hand, [tex]HCO_{3}[/tex] ,[tex]NH_{4}[/tex]+, and [tex]H_{2}[/tex][tex]O_{4}[/tex]P can all act as both brönsted acids and bases depending on the reaction conditions.

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(B) NH4⁺,  cannot act as both a Brønsted acid and a Brønsted base.

A Brønsted acid is a species that can donate a proton (H⁺), while a Brønsted base is a species that can accept a proton (H⁺).

(A) HCO3⁻ can act as an acid by donating a proton to form CO3²⁻ or as a base by accepting a proton to form [tex]H_{2}CO_{3}[/tex].
(C) HS⁻ can act as an acid by donating a proton to form S²⁻ or as a base by accepting a proton to form [tex]H_{2}S[/tex].
(D) H2PO4⁻ can act as an acid by donating a proton to form HPO4²⁻ or as a base by accepting a proton to form [tex]H_{3}PO_{4}[/tex].

However,
(B) NH4⁺ can only act as a Brønsted acid by donating a proton to form [tex]NH_{3}[/tex] but cannot act as a Brønsted base since it has no lone pair of electrons to accept a proton.

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Okay, let's solve this step-by-step without using quadratics:

1) The equilibrium constant Kc = 0.36 means the equilibrium lies to the left. So there will be more N2O4 than NO2 at equilibrium.

2) The initial concentration of N2O4 is 0.1 mol dm^-3. Let's call this [N2O4]initial.

3) At equilibrium, the concentrations of N2O4 and NO2 will be [N2O4]equil and [NO2]equil respectively.

4) We know the equilibrium constant expression for this reaction is:

Kc = ([NO2]equil)^2 / [N2O4]equil

5) Setting this equal to 0.36 and plugging in 0.1 for [N2O4]initial, we get:

0.36 = ([NO2]equil)^2 / (0.1 - [NO2]equil)

6) Simplifying, we get:

0.036 = [NO2]equil^2

7) Taking the square root of both sides, we get:

[NO2]equil = 0.06 mol dm^-3

So the equilibrium concentration of NO2 is 0.06 mol dm^-3.

Let me know if you have any other questions! I can also provide a more step-by-step explanation if needed.

The moles of NaF that must be dissolved in 1.00 liter of a saturated solution of PbF₂ at 25˚C to reduce the [Pb²⁺] to 1 x 10⁻⁶ molar is 2.0 x 10⁻⁵.

The solubility product expression for PbF₂ is given by:

At equilibrium, the product of the ion concentrations must be equal to the solubility product constant. We are given that the [Pb²⁺] in the saturated solution is 1 x 10⁻⁶ M. Therefore, we can use the Ksp expression to calculate the concentration of F- in the solution:

Now, we can calculate the amount of NaF needed to reduce the [F⁻] concentration to 2.0 x 10⁻¹ M. Since NaF is a 1:1 electrolyte, the concentration of F- will be equal to the concentration of NaF added.

However, we need to dissolve this amount of NaF in a saturated solution of PbF₂. Therefore, we need to check that the amount of NaF we added will not exceed the maximum amount that can dissolve in the solution at 25˚C.

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The number of grams of argon needed to fill a light bulb with a volume of 0.475 liters at 0 degrees Celsius and 1.5 atmospheres can be calculated using the ideal gas law.

The ideal gas law states that the product of pressure, volume, and temperature (in Kelvin) is equal to the number of moles of gas times the ideal gas constant (R). To convert Celsius to Kelvin, add 273.15.

Therefore, the number of moles of argon can be calculated as (1.5 atm)(0.475 L)(273.15 K) / (0.082 L atm K mol-1) = 68.9 moles. Since there are 28.0 g of argon in one mole, the total number of grams of argon needed to fill the light bulb is 68.9 moles x 28.0 g/mol = 1940 gb.

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The given equation for testing the presence of lead cations (Pb) using potassium chromate (K₂CrO₄) is incorrect. The correct equation is Pb(aq) + K₂CrO₄(aq) ⇒ PbCrO4(s) + 2K+(aq).

The incorrect equation, Pb(aq) + CrO₄(aq) ⇔ PbCrO(aq), is incorrect because it does not take into account the charge balance of the species involved in the reaction. In the correct equation, two potassium ions (2K+) are formed as counter ions to balance the charge on the lead chromate (PbCrO₄) precipitate.

In addition, the incorrect equation refers to PbCrO(aq), which implies that lead chromate is in a dissolved state. However, lead chromate is highly insoluble in water and precipitates as a yellow solid. Therefore, the correct equation includes the formation of a solid precipitate of lead chromate.

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The complete question is:

Group 1 cations precipitate easily in a relatively high concentration of hydrochloric acid. After the separation from the other group 1 cations, the presence of lead can be tested by addition of potassium chromate. Explain what is wrong with the given equation for this test. Pb(aq) + CrO₄(aq) ⇔ PbCrO(aq)

As a result, it is important to store NaOH in a dry and cool place, away from any sources of moisture or water.

NaOH, also known as sodium hydroxide, is a highly hygroscopic solid. This means that it can easily absorb moisture from its surroundings, including the air. When NaOH absorbs water, it can become more corrosive and potentially dangerous.

This is why it is also important to handle NaOH with care and wear appropriate protective gear, such as gloves and goggles. Additionally, any spills or leaks should be cleaned up immediately and properly disposed of according to local regulations.

By following these precautions, NaOH can be safely used in a variety of applications, including in the production of soap, paper, and textiles.

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The correct answer is option D. All of the above. It is necessary to slowly add the sulfuric acid to the p-cresol/acetic acid mixture in the test tube to prevent any accidents or injuries.

If sulfuric acid is added too soon, the solution may boil and the acid will spew out of the test tube, perhaps resulting in burns.

Sulfuric acid is also an endothermic reaction, which means it takes energy from its surroundings and has the potential to crystallise or cause the solution to harden.

Last but not least, adding the sulfuric acid gradually enables more precise measurement of the supplied sulfuric acid volume.

It is crucial to gradually add the sulfuric acid to the test tube mixture of p-cresol and acetic acid as a result of all these considerations.

Complete Question:

Why would it be necessary to slowly add the sulfuric acid to the p-cresol/acetic acid mixture in the test tube?

Options:

A.  To ensure accurate measurement of the volume of sulfuric acid added.

B. To prevent the solution from boiling and splattering the acidic solution out of the test tube.

C. To prevent the endothermic reaction from solidifying the solution.

D. All of the above.

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The pressure of gas is 1.05 atm when a 1.25 g sample of CO₂ is contained in a 750ml flask at 22.5°C.

Molecular weight of CO₂ is 1.25g ,Volume of CO₂ is 750ml,Temperature of CO₂ is 22.5°C and the gas constant is 0.08206 L atm/mol K.

Using the ideal gas law equation the pressure is found to be 1.05 atm.

To calculate the pressure of the gas, we can use the ideal gas law equation: [tex]PV=nRT[/tex]
Where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature in Kelvin.
First, we need to convert the volume to liters by dividing by 1000: 750 ml = 0.75 L.
Next, we need to calculate the number of moles of CO₂ present in the flask. We can use the molecular weight of CO₂ to convert from grams to moles:

[tex]1.25 * (1 /44.01 ) = 0.0284 mol[/tex]
Now we can plug in the values into the ideal gas law equation:

[tex]PV=nRT[/tex]
[tex]P * 0.75 L = 0.0284 mol  * 0.08206 L*atm/mol*K * (22.5 + 273.15) K[/tex]
Simplifying and solving for P, we get:
[tex]P = (0.0284 * 0.08206 * 295.65) / 0.75 = 1.05 atm[/tex]
Therefore, the pressure of the gas in the flask is 1.05 atm.

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False. In a closed system, matter can not enter or exit that is there is no change in the matter of the system.

Three types of systems exist in nature:

1. Open System: In this system, the matter can interact with the surroundings or matter can enter or exit the system from the surrounding. Similarly, the energy of the system also interacts with its surroundings and can be lost or gained.

For example oceans etc.

2. Closed system: In this system, the matter is unable to interact with the surroundings that are matter can't exit or enter the system. While the energy of the system is able to interact with the surroundings.

For example Earth etc

3. Isolated system: In this system, both matter and energy are unable to interact with the surrounding. There is no exchange between matter and the energy of surroundings.

For example thermos-teel bottles etc.

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Yes, the reaction worked. Three key signals that suggest the reaction worked include the appearance of the product, the presence of the expected starting material, and the absence of any other byproducts.

The product, 1-methoxy-2-chloro-4-nitrobenzene, can be identified by its distinct color, smell, and boiling point. Additionally, if the expected starting material is present, then it shows that the reaction has taken place.

Lastly, the absence of any other byproducts such as unreacted starting material implies that the reaction was successful. All together, all three signals indicate that the reaction worked.

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The concentration in molarity of the solution is 2.72 M.

To calculate the molarity of the solution, we need to first calculate the number of moles of KOH present in the solution.

Next, we need to calculate the volume of the solution in liters.

Finally, we can calculate the molarity of the solution using the formula:

Therefore, the concentration in molarity of the solution made by dissolving 20.0 grams of KOH in 150.0 mL of H2O is 2.72 M.

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The pattern in the graph may be explained by selection for large males over small males. Large males are more successful in defending territory, so they are more likely to reproduce and pass on their genes.

Territory is an area of land, sea or airspace with a defined boundary that is under the jurisdiction of a particular state, nation or governing body. It is often used to refer to a region or area with specific political, cultural, geographical or historical characteristics. Territory can also refer to a section of a country or region, or a group of related countries or regions, that are considered to be part of a larger political entity. In international law, a territory is an area that is subject to the authority of a state, but is not considered to be part of the state itself.

Over time, this has led to an increase in the proportion of large males relative to small males, resulting in the shifted distribution shown in the graph.

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Energetic molecules such as NADH and ATP are often reactants of exergonic reactions.

Exergonic reactions are those that discharge energy and have a harmful Gibbs-free energy change. In these reactions, the reactants have more free energy than the products, so the excess energy is cast in the state of heat. An exergonic reaction is a chemical reaction where the shift in the free energy is negative.

Energetic molecules like NADH and ATP store energy in their chemical adhesives, which can be emitted in exergonic reactions to drive endergonic responses that need energy input. Therefore, they are usually employed as reactants in exergonic reactions.

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In an equilibrium mixture of 1m each of CO² and H² at 25 degrees, the substance with the highest concentration is CO².

This is because when these two substances are brought together, they will react to form water and Carbon Monoxide (CO). The reaction is exothermic, meaning that energy is released in the form of heat.

This energy will cause the reaction to favor the formation of CO² over H², as H² requires more energy to form. As a result, the equilibrium mixture will have a higher concentration of CO² than H².

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Answer: NA = no of molecules / no of moles

NA = no of molecules × molecular weight /weight

Explanation:

To calculate the total hardness of the water sample, we need to first convert the concentrations of Ca2+ and Mg2+ from mg/L to mEq/L:

1 mEq/L = atomic weight (mg/L) / valence

The atomic weights and valences for Ca2+ and Mg2+ are:

Ca2+: atomic weight = 40.08 g/mol, valence = 2

Mg2+: atomic weight = 24.31 g/mol, valence = 2

Converting the concentrations to mEq/L:

Ca2+: (90 mg/L) / (40.08 g/mol / 2) = 2.24 mEq/L

Mg2+: (45 mg/L) / (24.31 g/mol / 2) = 1.85 mEq/L

The total hardness of the water sample is the sum of the molar concentrations of Ca2+ and Mg2+:

Total hardness = 2.24 mEq/L + 1.85 mEq/L = 4.09 mEq/L

To express the total hardness as mg/L as CaCO3, we can use the conversion factor of 1 mEq/L = 50 mg/L as CaCO3:

Total hardness = 4.09 mEq/L x 50 mg/L as CaCO3/mEq = 204.5 mg/L as CaCO3

Based on the total hardness value, this water sample would be classified as "hard water."

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Answer:

432 grams of Ag

Explanation:

First, we need to determine the limiting reagent between Mg and AgNO3.Using the stoichiometry of the balanced chemical equation, we can see that 1 mole of Mg reacts with 2 moles of AgNO3 to produce 2 moles of Ag.

The number of moles of Mg present in 48 grams can be calculated as:

48 g / 24 g/mol = 2 moles Mg

Now, let's calculate the number of moles of Ag that can be produced from 2 moles of Mg:

2 moles Mg x (2 moles Ag / 1 mole Mg) = 4 moles Ag

Finally, we can calculate the mass of Ag produced by multiplying the number of moles of Ag by its molar mass:

4 moles Ag x 108 g/mol = 432 grams Ag

Therefore, 48 grams of Mg will produce 432 grams of Ag in this reaction.

The reaction of both cis and trans isomers of 2,3-dimethyloxirane with HBr gives butane-2,3-diol. However, one of these stereoisomers gives a single achiral product, while the other gives two chiral enantiomers.

The reaction of 2,3-dimethyloxirane with itself is an example of an intramolecular nucleophilic substitution reaction.

The cis isomer of 2,3-dimethyloxirane has a plane of symmetry and is therefore an achiral molecule. When it reacts with itself, it will only form a single product nucleophilic substitution reaction.

The trans isomer of 2,3-dimethyloxirane is a chiral molecule and does not have a plane of symmetry. When it reacts with itself, it will form two enantiomers of the product, one being the mirror image of the other.

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The term defined as a pollutant that is formed by a chemical reaction between a primary pollutant and another compound in the atmosphere (either natural or human-made) is "secondary pollutant".

Primary pollutants are directly emitted into the atmosphere from sources such as cars, factories, and power plants. Examples of primary pollutants include carbon monoxide (CO), sulfur dioxide (SO₂), and nitrogen oxides (NOₓ).

Secondary pollutants, on the other hand, are not directly emitted into the atmosphere, but are formed through chemical reactions between primary pollutants and other compounds in the atmosphere. Examples of secondary pollutants include ground-level ozone (O₃), which is formed through the reaction of NOₓ and volatile organic compounds (VOCs), and acid rain, which is formed through the reaction of SO₂ and NOₓ with water, oxygen, and other chemicals in the atmosphere.

The formation of secondary pollutants is often dependent on factors such as temperature, sunlight, and the presence of other chemicals in the atmosphere. Secondary pollutants can be just as harmful to human health and the environment as primary pollutants, and are an important consideration in air pollution control strategies.

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The two types of the information are found in the elements box in the periodic table are Atomic number and the Chemical symbol. The correct option are B and D.

The atomic number of the element can be defines as the number of the protons of the element. The neutral atom contains the number of the electrons will equal to the number of the protons.

There are the total 118 elements in the periodic table and the elements are classified into the different group and the periods. The Elements for the same number of the valence electrons and they have the similar physical and the chemical properties that are classified into the group. Therefore, the correct option are B and D.

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A 100.0-mL buffer solution is 0.175 M in HClO and 0.150 M in NaClO

The pH of a solution gives a measure of the concentration of hydronium ions in the solution, and therefore, indicates the level of acidity or basicity of the solution.

We have a buffer solution made of 0.175 M HClO and 0.150 M NaClO

Part A :

pH of buffer solution can be calculated using equation, which is given below

pH =  pKa +  log  [ Base]/[Acid]

We have [acid] = [ HClO] = 0.175 M

[Base] = [NaClO] = 0.150 M

Ka of HClO is 3.5 x 10⁻⁸   (  Note : Ka value is taken from online resource. Please check the value given to you and make the changes accordingly)

pKa =  - log ( Ka)

pKa = - log ( 3.5 x 10⁻⁸)

pKa = 7.46

pH =   7.46 +  log  ( 0.150/0.175)

pH = 7.46 + ( -0.0669)

pH = 7.39

Part B:

When we add HBr to this buffer, basic component of buffer which is NaClO would try to neutralize effect of acid HBr.

Let's write the reaction that takes place here

HBr  +   NaClO  ------------->  HClO   +   NaBr

Let's find moles of HBr , HClO and NaClO we have

mol HBr = 150 mg HBr x  1 g/1000 mg x   1mol / 80.9 g = 0.00185 mol

mol NaClO = 100 mL x 1 L/1000 mL x  0.150 mol/L = 0.015 mol

mol HClO = 100 mL x 1 L/1000 mL x  0.175 mol/L = 0.0175 mol

pH = 7.46 +  log ( 0.01315/0.01935)   ( Note : we can use mole values instead of concentration terms in this case)

pH = 7.46 + (-0.1678)

pH = 7.29

Part C:

When NaOH is added to the buffer, acidic component , HClO of the buffer tries to neutralize its effect.

The reaction  given below

NaOH  +  HClO ----->  NaClO +   H2O

mol NaOH = 85 mg NaOH x 1 g/1000 g x 1 mol/40 g = 0.002125 mol

Equilibrium mol of base NaClO = 0.0171 and acid , HClO= 0.0154

pH = 7.46 +  log ( 0.0171/0.0154)

pH = 7.46 + 0.0455

pH = 7.51.

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Complete question:

1) A 100.0-mL buffer solution is 0.175 M in HClO and 0.150 M in NaClO.

Part A: What is the initial pH of this solution?

Part B: What is the pH after addition of 150.0 mg of HBr?

Part C: What is the pH after addition of 85.0 mg of NaOH?

To determine the initial pH of the buffer solution, we can use the Henderson-Hasselbalch equation:

pH = pKa + log([base]/[acid])

where pKa is the dissociation constant of the weak acid (HClO), [base] is the concentration of the conjugate base (ClO-), and [acid] is the concentration of the weak acid (HClO).

First, we need to calculate the pKa of HClO. The Ka of HClO is 3.0 x 10^-8, so the pKa is:

pKa = -log(Ka) = -log(3.0 x 10^-8) = 7.52

Next, we can plug in the concentrations of HClO and NaClO into the Henderson-Hasselbalch equation:

pH = 7.52 + log(0.150/0.175)

pH = 7.52 - 0.080

pH = 7.44

Therefore, the initial pH of the buffer solution is 7.44.

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The change of state described is melting (option C). In melting, the particles of a substance gain energy and change from a regular ordered structure to a disordered structure with large distances between the particles, which results in the substance changing from a solid to a liquid state.

Melting is a physical process in which a substance changes from its solid state to its liquid state. It occurs when a solid substance absorbs enough heat energy to overcome the forces of attraction between its particles, causing the particles to move faster and become less ordered.

As a result, the substance loses its definite shape and takes the shape of the container in which it is placed, while retaining its volume. The temperature at which a substance melts is known as its melting point.

An example of melting is the melting of ice. At the melting point of water, which is 0°C (32°F) at standard pressure, ice changes from its solid state to its liquid state. The resulting liquid water takes the shape of its container, such as a glass, but still has the same volume as the ice from which it was melted.

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The axial stereoisomer is the most reactive in this type of reaction.

In an SN2 reaction with intramolecular catalysis, the most reactive stereoisomer is the one with an axial thioether group.

This is because in the axial position, the thioether group is closer to the leaving group (chlorine), allowing for more efficient overlap of their orbitals and a lower energy transition state.

The equatorial thioether group is farther away from the leaving group, resulting in a higher energy transition state and a slower reaction. Therefore, the axial stereoisomer is the most reactive in this type of reaction.

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