Acetonitrile (CH3CN) is an important industrial cheical. Among other things, it Is used to make plastic moldings, which have multiple uses, from car parts to Lego bricks. Which statement below about acetonitrile is FALSE? a. Acetonitrile has 16 valence electrons in its Lewis structure. b. Acetonitrile has one triple bond. C. Acetonitrile has one pair of nonbonding electrons. d. All atoms satisfy the octet rule in acetonitrile. e. One carbon atom and the nitrogen atom have nonzero formal charges.

Answer:

There is 1.3 kJ heat produced(released)

Explanation:

Step 1: Data given

Volume of a 0.200 M Nacl solution = 100 mL = 0.1 L

Volume of a 0.200 M AgNO3 solution = 100 mL = 0.1 L

Initial temperature = 21.9 °C

Final temperature = 23.5 °C

Solid AgCl will be formed

Step 2: The balanced equation:

AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq)

AgCl(s) + NaNO3(aq) → Na+(aq) + NO3-(aq) + AgCl(s)

Step 3: Define the formula

Pressure is constant.  → the heat evolved from the reaction is equivalent to the enthalpy of reaction.  

Q=m*c*ΔT

⇒ Q = the heat transfer (in joule)

⇒ m =the mass (in grams)

⇒ c= the heat capacity (J/g°C)

⇒ ΔT = Change in temperature = T2- T1

Step 4: Calculate heat

Let's vonsider the density the same as the density of water (1g/mL)

Mass = volume * density

Mass = 200 mL * 1g/mL

Mass = 200 grams

Q= m*c*ΔT

⇒ m = 200 grams

⇒ c = the heat capacity (let's consider the heat capacity of water) = 4.184 J/g°C

⇒ ΔT = 23.5 -21.9 = 1.6°C

Q = 200 * 4.184 * 1.6 = 1338 .9 J = 1.3 kJ

There is 1.3 kJ heat produced(released)

Therefore, we assumed no heat is absorbed by the calorimeter, no heat is exchanged between the  calorimeter and its surroundings, and the specific heat and mass of the solution are the same as those for  water (1g/mL and 4.184 J/g°C)

The increased temperature after the precipitation reaction of NaCl and AgNO3 in a coffee cup calorimeter indicates that heat is released. Calculation of the heat released depends on the specific heat capacity of the solution and its mass. Some assumptions made include the solution having the same heat capacity and density as water, and perfect insulation of the calorimeter.

The heat released by the precipitation reaction of NaCl and AgNO3 to form AgCl can be deduced from the increase of temperature observed in the coffee cup calorimeter. The process happens when Ag+ from AgNO3(aq) and Cl- ion from NaCl(aq) react to form the solid AgCl. This reaction is exothermic as it leads to an increase in the temperature of surroundings, that is, the solution in the calorimeter.

To calculate the heat produced, we need the specific heat capacity of the solution, which is assumed to be approximately equal to that of water (4.18 J/g°C), and the total mass of the solution which is calculated by adding the volumes of the two solutions since the density of the solution is assumed to be approximately 1 g/mL (same as water).

The approximations made in this calculation include treating the solution as having the same specific heat capacity and density as pure water, and assuming that the calorimeter perfectly insulates the solution so that no heat is lost to the environment.

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Answer:

The correct answer is C fatty acid oxidation would stop when all of the CoA is bound as acetyl CoA.

Explanation:

Acetyl CoA is the principle end product of beta oxidation of even chain fatty acid such as palmitic acid.

    When the cellelar label of actyl CoA increases at that time the excess acetyl CoA is converted to ketone bodies by the process called ketogenesis.

 According to the question if the excess acetyl CoA is not converted to ketone bodies then it will interfere with the oxidation of fatty acid because fatty acid molecules will not get any CoA SH molecule to activate themselves to initiate a new round of beta oxidation.

As a result fatty acid oxidation will stop.

Answer:

C. Fatty acid oxidation would stop when all of the CoA is bound as acetyl‑CoA.

Explanation:

Hello,

In this case, due to the fact that the mitochondrial pool of the CoA is short, thus, such cofactor must be recycled from acetyl-CoA through the production of ketone-like bodies. Therefore, the operation of the beta-oxidation pathway is performed, as it is necessary for energy production, in such a way one concludes that fatty acid oxidation would stop when all of the CoA is bound as acetyl‑CoA.

Best regards.

Answer:

2-methoxy-2-methylpropane

Explanation:

The first step for this reaction is the carbocation formation. In this step, a tertiary carbocation is formed. Also, we will have a good leaving group so bromide will be formed. Then the methanol acts as a nucleophile and attacks the carbocation. Next, a positive charge is generated upon the oxygen, this charge can be removed when the hydrogen leaves the molecule as [tex]H^+[/tex]. (See figure)

Answer:

C.) Both substances are made up of nonpolar molecules

Explanation:

Bromine is soluble in mineral oil because both substances are made of nonpolar molecules.A solute is highly soluble in a solvent that has the same chemical structure as it has. Bromine is a diatomic molecule that has dipole moments that cancel out to form a non-polar molecular. Mineral oil contains Carbon atoms bonded to hydrogen atoms forming nonpolar molecules.

Answer:

2.04 is the pOH of a 0.0092 M CsOH solution.

Explanation:

Molarity of cesium hydroxde = [CsOH]= 0.0092

[tex]CsOH(aq)\rightarrow Cs^+(aq)+OH^-(aq)[/tex]

1 mole of cesium hydroxide gives 1 mole of cesium ion and 1 mole of hydroxide ion.

Then 0.0092 M cesium hydroxide will give :

[tex][OH^-]=1\times [CsOH]=1\times 0.0092 M=0.0092M [/tex]

The pOH of the solution is the negative logarithm of concentration of  hydroxide ions in a solution.

[tex]pOH=-\log [OH^-][/tex]

[tex]pOH=-\log [0.0092 M]=2.0362\approx 2.04 [/tex]

2.04 is the pOH of a 0.0092 M CsOH solution.

Final answer:

The pOH of a 0.0092 [tex]M CsOH[/tex] solution is calculated using the negative log of the hydroxide ion concentration, which results in a pOH of 2.04. Thus, the correct answer is (A) 2.04.

Explanation:

The student is asking about how to calculate the pOH of a [tex]CsOH[/tex] solution. Since CsOH is a strong base, it will dissociate completely in water.

The concentration of hydroxide ions (OH-) in a 0.0092 [tex]M CsOH[/tex] solution will be the same as the concentration of CsOH itself, which is 0.0092 M.

To find the pOH, we take the negative logarithm (base 10) of the hydroxide ion concentration:

[tex]pOH = -log[OH-][/tex]
[tex]pOH = -log(0.0092)[/tex]
[tex]pOH = -(-2.036)[/tex]
[tex]pOH = 2.036[/tex]

Therefore, rounding to two decimal places, the pOH of a 0.0092 [tex]M CsOH[/tex] solution is 2.04. Hence, the correct answer is (A) 2.04.

Answer:

I. heating the helium

Explanation:

Final answer:

(I) Heating the helium and (IV) decreasing the pressure outside the container are the two processes that will cause the piston to move away from the base and decrease the pressure of the gas. Hence, (c) is the correct option.

Explanation:

Assuming ideal gas behavior, the question asks which processes will lead the piston to travel away from the base and lower the helium gas's pressure. Let's examine each of the scenarios that are presented:

I. Heating the helium: Heating increases the internal energy of the gas molecules, making them move faster. This increases the force they exert against the piston, pushing it outward and increasing the volume, thus reducing the pressure according to Boyle's Law (P₁V₁ = P₂V₂).

II. Removing some of the helium from the container: If you remove some of the helium, there will be fewer molecules to exert force on the piston, leading to a decrease in pressure. However, the piston will not necessarily move since the external pressure remains the same. Without a corresponding change in external pressure, there is no force to move the piston outward.

III. Turning the container on its side: Turning the container on its side will have no effect on the pressure or volume of the gas if the external conditions remain the same. The position of the piston is influenced by forces and pressures, not by its orientation in space.

IV. Decreasing the pressure outside the container: Decreasing the external pressure acting on the piston will allow the internal pressure of the gas to push the piston outward, increasing the volume and therefore decreasing the gas pressure, as explained by the ideal gas law (PV = nRT).

Therefore, the processes that will cause the piston to move away from the base and decrease the pressure of the gas are heating the helium and decreasing the pressure outside the container. So the correct answer to the question is (c) 2.

Answer:

ΔH of reaction is -856 kJ/mol

Explanation:

The property ΔH is property which can be added to find the net change in enthalpy of reaction.

ΔH of first reaction is -665.9 kJ/mol

ΔH of second reaction is 190.1 kJ/mol

carefully looking at the third equation,

it is first reaction - second reaction.

thus, by Hess's law,

Hess's Law of Constant Heat Summation (or just Hess's Law) states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes.

ΔH of third reaction is = [tex]-665.9 - (190.1)[/tex]

ΔH =  -856 kJ/mol

Answer : The specific heat of metal is [tex]0.481J/g^oC[/tex].

Explanation :

In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.

[tex]q_1=-q_2[/tex]

[tex]m_1\times c_1\times (T_f-T_1)=-m_2\times c_2\times (T_f-T_2)[/tex]

where,

[tex]c_1[/tex] = specific heat of metal = ?

[tex]c_2[/tex] = specific heat of water = [tex]4.184J/g^oC[/tex]

[tex]m_1[/tex] = mass of metal = 129.00 g

[tex]m_2[/tex] = mass of water = 45.00 g

[tex]T_f[/tex] = final temperature = [tex]39.6^oC[/tex]

[tex]T_1[/tex] = initial temperature of metal = [tex]97.8^oC[/tex]

[tex]T_2[/tex] = initial temperature of water = [tex]20.4^oC[/tex]

Now put all the given values in the above formula, we get

[tex]129.00g\times c_1\times (39.6-97.8)^oC=-45.00g\times 4.184J/g^oC\times (39.6-20.4)^oC[/tex]

[tex]c_1=0.481J/g^oC[/tex]

Therefore, the specific heat of metal is [tex]0.481J/g^oC[/tex].

To calculate the specific heat of the metal, the heat transfer equation q=mcΔT is used. By setting the heat lost by the metal equal to the heat gained by the water, and substituting the known values into the equation, we can solve for the specific heat of the metal.

The specific heat of a metal can be calculated by using the concept of heat transfer, where heat lost by the metal is equal to the heat gained by the water in a calorimetry experiment. The equation is q = mcΔT, where q is the heat transfer, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. For the water, the heat gained can be calculated as qwater = mwatercwaterΔTwater. For the metal, the heat lost is qmetal = mmetalcmetalΔTmetal. Given that the heat lost by the metal equals the heat gained by the water, the equation can be set up to solve for the specific heat of the metal, cmetal = (qwater / (mmetalΔTmetal)). We know the following: mwater = 45.00 g, cwater = 4.184 J/g/C, ΔTwater = final temperature - initial temperature of water, mmetal = 129.00 g, ΔTmetal = initial temperature of metal - final temperature. By substituting these values into the equation, we can find the specific heat of the metal.

Answer:

Is not possible to make a buffer near of 7.

Optimal pH for sulfate‑based buffers is 2.

Explanation:

The dissociations of H₂SO₄ are:

H₂SO₄ ⇄ H⁺ + HSO₄⁻ pka₁ = -10

HSO₄⁻ ⇄ H⁺ + SO₄²⁻ pka₂ = 2.

The buffering capacity is pka±1. That means that for H₂SO₄ the buffering capacity is in pH's between -11 and -9 and between 1 and 3, having in mind that pH's<0 are not useful. For that reason, is not possible to make a buffer near of 7.

The optimal pH for sulfate‑based buffers is when pka=pH, that means that optimal pH is 2.

I hope it helps!

Answer:

C.

Explanation:

The entropy (S) is the measure of the randomness of a system, and ΔS = Sfinal - Sinitial. As higher is the disorder of the system, as higher is the entropy.

A. When KCl is fractionated in power, there'll be more portions of it, so, the disorder must be higher, then ΔS is positive.

B. As higher is the temperature, higher is the kinetic energy of the system, and because of that, the disorder is also higher, so ΔS is positive.

C. The decrease in the volume (compression) decreases the distance between the molecules, so the system will be more organized, then ΔS is negative.

D. The volume before the mixing will be higher, and the ethanol will dissociate, so it will be more particles, the disorder will increase, and ΔS is positive.

E. Sgas > Sliquid > Ssolid because of the disorder of the molecules, then ΔS is positive.

Final answer:

The process with a negative change in entropy (ΔS) is compressing 1 mol Ne at constant temperature from 1.5 L to 0.5 L, as it leads to a decrease in volume and increases the orderliness of the system.

Explanation:

The question asks for which process the change in entropy (ΔS) is negative. Entropy generally refers to the measure of disorder or randomness in a system. A negative ΔS indicates a decrease in entropy, meaning the system becomes more ordered. Considering the options:

A. grinding a large crystal of KCl to powder - Increases disorder by breaking down the crystal structure, so ΔS is positive.

B. raising the temperature of 100 g Cu from 275 K to 295 K - Increases thermal motion and disorder, so ΔS is positive.

C. compressing 1 mol Ne at constant temperature from 1.5 L to 0.5 L - Decreases the volume and increases order, so ΔS is negative.

D. mixing 5 mL ethanol with 25 mL water - Mixing increases disorder, so ΔS is positive.

E. evaporation of 1 mol of CCl4(l) - Changing from liquid to gas increases disorder, so ΔS is positive.

Therefore, the process with a negative ΔS is C. compressing 1 mol Ne at constant temperature from 1.5 L to 0.5 L.

Answer:

At equilibrium, Kc = 0.058

Explanation:

Step 1: Data given

Mol SO3 = 12.6

Volume = 4.0 L

At equilibrium we have:

3.4 mol of SO2

Step 2: The balanced equation

2SO3(g) + ⇆ 2SO2(g) + O2(g)

Step 3: ICE-chart

The initial number of moles are:

SO3: 12.6 moles

SO2 : 0 mol

O2: 0 mol

There will react:

SO3: -2x

SO2: +2x

O2: +x

The number of moles at the equilibrium are:

SO3: 12.6 - 2x

SO2: 2x  = 3.4 mol

O2: x

Since at the equilibrium, we have 2x = 3.4 mol. x = 1.7 mol

This means at the equilibrium we have 1.7 mol of O2 and 12.6 -3.4 = 9.2 mol of SO3

Step 4: Calculate the equilibrium constant Kc

Kc = [3.4/4]² *[1.7/4] / [9.2/4]²

Kc = 0.058

At equilibrium, Kc = 0.058

The complexes are sodium hexachloroplatinate(IV), potassium trisoxalatoferrate(III), and pentaamminechlorocobalt(III) chloride.

(a) There are two Na+ ions, so the coordination sphere has a negative two charge: [PtCl6]². There are six anionic chloride ligands, so -2 = -6 + x, and the oxidation state of the platinum is 4+. The name of the complex is sodium hexachloroplatinate(IV), and the coordination number is six.

(b) The coordination sphere has a charge of 3- (based on the potassium) and the oxalate ligands each have a charge of 2-, so the metal oxidation state is given by -3 = -6+ x, and this is an iron(III) complex. The name is potassium trisoxalatoferrate(III) (note that tris is used instead of tri because the ligand name starts with a vowel). Because oxalate is a bidentate ligand, this complex has a coordination number of six.

(c) In this example, the coordination sphere has a cationic charge of 2+. The NH3 ligand is neutral, but the chloro ligand has a charge of 1-. The oxidation state is found by +2 = -1 + x and is 3+, so the complex is pentaamminechlorocobalt(III) chloride and the coordination number is six.

Answer:

The correct answer is a  coenzyme cosubstrate is loosely bound to an enzyme and dissociates in an altered form as the part of the catalytic cycle.Its original form is regenerated not by the cycle but by other enzyme.

Explanation:

The  prosthetic group of the enzyme pyruvate dehydrogenase is

2 TPP or Thymine pyrophosphate.

3  Lipomide.

Answer: The change in temperature is 84.7°C

Explanation:

To calculate the change in temperature, we use the equation:

[tex]q=mc\Delta T[/tex]

where,

q = heat absorbed = 1 kCal = 1000 Cal    (Conversion factor: 1 kCal = 1000 Cal)

m = mass of steel = 100 g

c = specific heat capacity of steel = 0.118 Cal/g.°C

[tex]\Delta T[/tex] = change in temperature = ?

Putting values in above equation, we get:

[tex]1000cal=100g\times 0.118cal/g^oC\times \Delta T\\\\\Delta T=\frac{1000cal}{100g\times 0.118cal/g^oC}\\\\\Delta T=84.7^oC[/tex]

Hence, the change in temperature is 84.7°C

Answer:

D.) The higher vapor pressure of acetone results in more rapid evaporation and heat loss

Explanation:

Acetone being liquid with very low boiling point and hence can be easily be converted to gaseous state .

And ,

Therefore have higher vapour pressure and as liquid gets converted to gas , the process of evaporation takes place and leads to loss of heat .

Hence , from the given options , the most appropriate option according to given statement of the question is ( d ) .

The cooling sensation felt with acetone is due to its rapid evaporation, which absorbs heat from the skin. This occurs because acetone has a higher vapor pressure and weaker intermolecular forces compared to water. Option D is the correct option.

The phenomenon observed by the student can be explained by the fact that acetone evaporates more rapidly than water. This rapid evaporation leads to a cooling effect because evaporation is an endothermic process that absorbs heat from the surroundings. Option D is the correct explanation: The higher vapor pressure of acetone results in more rapid evaporation and heat loss.

Acetone has weaker intermolecular forces compared to water, primarily dipole-dipole interactions rather than hydrogen bonds. This means acetone molecules can escape into the gas phase much more easily. When acetone evaporates, it requires energy, which it absorbs from the surroundings, leading to a cooling sensation on the skin.

Answer: The Gibbs free energy of the reaction is -8.82 kJ/mol

Explanation:

The equation used to Gibbs free energy of the reaction follows:

[tex]\Delta G=\Delta G^o+RT\ln K_{eq}[/tex]

where,

[tex]\Delta G[/tex] = free energy of the reaction

[tex]\Delta G^o[/tex] = standard Gibbs free energy = -16.7 kJ/mol = -16700 J/mol  (Conversion factor: 1kJ = 1000J)

R = Gas constant = [tex]8.314J/K mol[/tex]

T = Temperature = [tex]37^oC=[273+37]K=310K[/tex]

[tex]K_{eq}[/tex] = Ratio of concentration of products and reactants = 21.3

Putting values in above equation, we get:

[tex]\Delta G=-16700J/mol+(8.314J/K.mol\times 310K\times \ln (21.3))\\\\\Delta G=-8816.7J/mol=-8.82kJ/mol[/tex]

Hence, the Gibbs free energy of the reaction is -8.82 kJ/mol

Answer:

a) f = 3.02x10¹⁵ s⁻¹, and λ = 99.4 nm.

b) 99.4 nm

Explanation:

a) The energy of radiation is given by:

E = h*f

Where h is the Planck constant (6.626x10⁻³⁴ J.s), and f is the frequency. To have the highest frequency, the energy must be the highest too, because they're directly proportional. So we must use E = -E1 = 20x10⁻¹⁹ J

20x10⁻¹⁹ = 6.626x10⁻³⁴xf

f = 3.02x10¹⁵ s⁻¹

The wavelenght is the velocity of light (3.00x10⁸ m/s) divided by the frequency:

λ = 3.00x10⁸/3.02x10¹⁵

λ = 9.94x10⁻⁸ m = 99.4 nm

b) To have the shortest wavelength, it must be the highest energy and frequency, so it would be the same as the letter a) 99.4 nm.

B

Carbon has 4 valence electrons that can be involved in the formation of a covalent bond. This is why it can form various types of bonds with itself or other elements. Depending on the number of valence electrons involved in the binding, the bond can be a single, double or triple bond.

Explanation:

Remember the atoms sharing electrons in a covalent bond are aimed at achieving stable electron configuration. Carbon (2.4) being in the middle of the 2nd period seeks to be either 2 or 2.8.

This is why carbon based structures can vary so much due to the large variability in which the carbon atoms can bond. Remember carbon is the same element that forms graphite, diamond, and coal.

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Answer:

8.46

Explanation:

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

Also, atomic number of I = 549

Thus, the number of protons = 49

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.

Mass number = Number of protons + Number of neutrons

105 =  49 + Number of neutrons

Number of neutrons = 56

Mass of neutron = 1.008665 amu

Mass of proton = 1.007825 amu

Calculated mass = Number of protons*Mass of proton + Number of neutrons*Mass of neutron

Thus,

Calculated mass = (49*1.007825 + 56*1.008665) amu = 105.868665 amu

Mass defect = Δm = |105.868665 - 104.914558| amu = 0.954107 amu

The conversion of amu to MeV is shown below as:-

1 amu = 931.5 MeV

So, Energy = 0.954107*931.5 MeV/atom = 888.750671 MeV/atom

Also, 1 atom has 105 nucleons (Protons+neutrons)

So, Energy = 888.750671 MeV/105nucleons = 8.46 MeV/nucleon

Answer:- 8.46

The binding energy per nucleon for an atom of 105In is calculated by determining the mass defect, converting it to energy using Einstein's mass-energy equivalence, and dividing by the number of nucleons.

To calculate the binding energy per nucleon in MeV for an atom of 105In with a mass of 104.914558 amu, we must first identify the number of protons and neutrons in the nucleus. Indium-105 has 49 protons (since In is the element with atomic number 49), and subtracting this from the mass number 105 gives us 56 neutons. The mass of the protons is 49 x 1.007825 amu, and the mass of the neutrons is 56 x 1.008665 amu.

Next, we calculate the mass defect by subtracting the atomic mass of the 105In from the combined mass of the protons and neutrons. To convert the mass defect into energy, we multiply by 931.5 MeV/amu, according to Einstein’s mass-energy equivalence principle (E=mc2). Lastly, we divide this energy by the total number of nucleons (protons + neutrons) to find the binding energy per nucleon.

Answer:

X is the chemical symbol of the element.

A is the mass number (number of protons neutrons).

Z is the atomic number (number of protons).

Explanation:

In stating the chemical representation of an element, the AZX symbol is used.

The symbol of the element may either come from its Latin or English name. For instance, the symbol of the element sodium, comes from its Latin name natrium (Na).

Its atomic number is the number of protons in the nucleus of the atom. For sodium, the atomic number is 11.

The mass number refers to the sum of the number of protons and neutrons in the atom. For sodium the mass number is 23.

Hence the AZX symbol for sodium is

23_11Na.

The correct option as regarding the definition of A, Z and X in ᴬ₂X are:

Nuclide of elements are generally represented according to the following notation:

ᴬ₂X

Where

With the above information, we can determine the options that is correct from the question.

Thus, the correct options are:

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Answer:

Option 4 is not the characteristics of esters

Explanation:

Esters :

They are organic compound derived from an organic or inorganic acid. in which one Hydroxyl (OH) group is replaced by an organic alkoxy (-O-R) group.

General formula of Esters:

Easter can be represented by a general formula that is

                                       RCOOR

where R is any alkyl group

No to look at the characteristics of the Esters an find out the odd one option that is not correct.

Option 1 is the characteristics of esters.

Esters are obtained from the reaction of carboxylic acid and an alcohol.

          CH₃COOH + CH₃OH -------------> CH₃COOCH₃ + H₂O

Option 2 is the characteristics of esters.

This option is also correct as if we see at its general formula

The carbonyl group attached to an Oxygen atom and this oxygen is attached to carbon of alkyl group

                                  O==C------OR

Option 3 is also the characteristics of esters

The odors and flavors of many flowers, perfumes, and ripe fruits is due to the presence of ester. as ester have now hydrogen bonding and low vapor pressure and highly volatile that's why it is responsible for odors.

Option 4 is not the characteristics of esters

This option is wrong, as the carbon atom in the middle of the carbon chain can not be easy to replace, also the carbonyl carbon is directly attached to oxygen group and not Carbon group.                    

Answer:

d

Explanation:

The complexes that involve metal having d10 electrons arrangement are usually colorless because:

A). There is no d electron that can be promoted via the absorption of visible light.

Thus, option A is the correct answer.

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Answer:

Explanation:ANd of course,

Δ

H

∘

f

=

0

for an element (here dixoygen) in its standard state

Answer:

a. ΔHr = 696,8 kJ/mol

b. ΔHr = -1164,7 kJ/mol

c. ΔHr = -467,9 kJ/mol

Explanation:

It is possible to obtain the standard enthalpy change of a reaction with the ΔH°f of products - ΔH°f reactants.

a. For the reaction:

N₂(g) + 3H₂O(l) → 2NH₃(aq) + ³/₂O₂(g)

ΔHr = 2ΔH°f NH₃(aq) + ³/₂ΔH°fO₂(g) - (3ΔH°fH₂O(l) + 2ΔH°f N₂(g))

ΔHr = 2×-80,3 kJ/mol + ³/₂×0 - (3×-285,8 kJ/mol + 0)

ΔHr = 696,8 kJ/mol

b. and c. For the reaction:

NH₃(aq) + 2CH₄(g) + ⁵/₂O₂(g) → NH₂CH₂COOH(s) + 3H₂O(l)

ΔHr = ΔH°fNH₂CH₂COOH(s) + 3ΔH°fH₂O(l) - (ΔH°fNH₃(aq) + 2ΔH°fCH₄(g) + ⁵/₂ΔH°fO₂(g))

ΔHr = -537,2kJ/mol + 3×-285,8 kJ/mol  - (-80,3 kJ/mol + 2×-74,8kJ/mol+ ⁵/₂×0)

ΔHr = -1164,7 kJ/mol

c. From nitrogen, methane and oxygen the reaction is the sum of reactions of a and b:

N₂(g) + 3H₂O(l) → 2NH₃(aq) + ³/₂O₂(g)

+ NH₃(aq) + 2CH₄(g) + ⁵/₂O₂(g) → NH₂CH₂COOH(s) + 3H₂O(l)

N₂(g) + 2CH₄(g) + O₂(g) → NH₂CH₂COOH(s) + NH₃(aq)

By Hess's law, the ΔHr will be the sum of the ΔHr of the last two reactions, that means:

ΔHr = -1164,7 kJ/mol + 696.8 kJ/mol

ΔHr = -467,9 kJ/mol

I hope it helps!

Answer:

(a) Cgas = 0.125 kJ/k

(b) cgas = 0.25kJ/kg.K

(c) cm(gas) = 0.021kJ/mol.K

Explanation:

18.9 kJ is equal to the sum of the heat absorbed by the gas and the heat absorbed by the calorimeter.

Qcal + Qgas = 18.9 kJ  [1]

We can calculate the heat absorbed using the following expression.

Q = C . ΔT

where,

C is the heat capacity

ΔT is the change in the temperature

(a) What is the heat capacity of the sample?

From [1],

Ccal . ΔT + Cgas . ΔT = 18.9 kJ

(2.22kJ/K) × 8.06 K + Cgas × 8.06 K = 18.9 kJ

Cgas = 0.125 kJ/k

(b) If the sample has a mass of 0.5 kilograms, what is the specific heat capacity of the substance?

We can calculate the specific heat capacity (c) using the following expression:

[tex]c=\frac{C}{m} =\frac{0.125kJ/K}{0.5kg} =0.25kJ/kg.K[/tex]

(c) If the sample is Krypton, what is the molar heat capacity at constant volume of Krypton? The molar mass of Krypton is 83.8 grams/mole.

The molar heat capacity is:

[tex]\frac{0.25kJ}{kg.K} .\frac{1kg}{1000g} .\frac{83.8g}{mol} =0.021kJ/mol.K[/tex]

Final answer:

The heat capacity of the sample is 2.34 kJ/K. The specific heat capacity of the substance is 4.68 kJ/(kg*K). The molar heat capacity at constant volume of Krypton is 0.0559 kJ/(mol*K).

Explanation:

The heat capacity of a substance is the amount of energy required to increase its temperature by 1 degree. The specific heat capacity is the amount of energy required to increase the temperature of 1 gram of a substance by 1 degree.

(a) To find the heat capacity of the sample, we can use the equation Q = CΔT, where Q is the amount of heat transferred, ΔT is the change in temperature, and C is the heat capacity. Rearranging the equation, C = Q/ΔT. Plugging in the given values, C = 18.9 kJ / 8.06 K

= 2.34 kJ/K.

(b) To find the specific heat capacity of the substance, we need to know the mass of the sample. Given that the mass is 0.5 kilograms, we can use the equation cs = C/m, where cs is the specific heat capacity, C is the heat capacity, and m is the mass. Plugging in the values, cs = 2.34 kJ/K / 0.5 kg

= 4.68 kJ/(kg*K).

(c) To find the molar heat capacity at constant volume of Krypton, we can use the equation Cm = cs / M, where Cm is the molar heat capacity, cs is the specific heat capacity, and M is the molar mass. Plugging in the values, Cm = 4.68 kJ/(kg*K) / 83.8 g/mol

= 0.0559 kJ/(mol*K).

the concentration of [tex]\(Sn^{2+}\)[/tex] is approximately [tex]\(3.3 \times 10^{-2} \, \text{M}\)[/tex].

To solve this problem, we can use the Nernst equation, which relates the cell potential [tex](\(E_{\text{cell}}\))[/tex] to the standard cell potential [tex](\(E^{\circ}_{\text{cell}}\))[/tex] and the concentrations of the species involved in the redox reaction:

[tex]\[ E_{\text{cell}} = E^{\circ}_{\text{cell}} - \frac{0.0592}{n} \log \left( \frac{[\text{cathode product}]^m}{[\text{anode product}]^n} \right) \][/tex]

Given the standard reduction potentials, we can determine that the number of electrons involved in the half-reactions is [tex]\(n = 2\)[/tex]. The given cell potential is [tex]\(E_{\text{cell}} = 0.660 \, \text{V}\)[/tex]. We need to find the concentration of [tex]\(Sn^{2+}\)[/tex].

First, let's write the Nernst equation for the given cell:

[tex]\[ 0.660 \, \text{V} = (E^{\circ}_{\text{cell}}) - \frac{0.0592}{2} \log \left( \frac{[\text{Sn}^{2+}]}{[\text{Zn}^{2+}]} \right) \][/tex]

We're given the standard reduction potentials, which are [tex]\(E^{\circ}_{\text{cell}} = -0.76 \, \text{V}\)[/tex] for the zinc half-reaction and [tex]\(E^{\circ}_{\text{cell}} = -0.136 \, \text{V}\)[/tex] for the tin half-reaction.

Plugging in the values and solving for [tex]\([\text{Sn}^{2+}]\)[/tex]:

[tex]\[ 0.660 \, \text{V} = (-0.76 \, \text{V}) - \frac{0.0592}{2} \log \left( \frac{[\text{Sn}^{2+}]}{2.5 \times 10^{-3}} \right) \][/tex]

[tex]\[ 0.660 \, \text{V} = (-0.76 \, \text{V}) - 0.0296 \log \left( \frac{[\text{Sn}^{2+}]}{2.5 \times 10^{-3}} \right) \][/tex]

[tex]\[ 0.660 + 0.76 = 0.0296 \log \left( \frac{[\text{Sn}^{2+}]}{2.5 \times 10^{-3}} \right) \][/tex]

[tex]\[ 0.0296 \log \left( \frac{[\text{Sn}^{2+}]}{2.5 \times 10^{-3}} \right) = 0.76 + 0.660 \][/tex]

[tex]\[ \log \left( \frac{[\text{Sn}^{2+}]}{2.5 \times 10^{-3}} \right) = \frac{1.42}{0.0296} \][/tex]

[tex]\[ \log \left( \frac{[\text{Sn}^{2+}]}{2.5 \times 10^{-3}} \right) = 47.973 \][/tex]

[tex]\[ \frac{[\text{Sn}^{2+}]}{2.5 \times 10^{-3}} = 10^{47.973} \][/tex]

[tex]\[ [\text{Sn}^{2+}] = (2.5 \times 10^{-3}) \times 10^{47.973} \][/tex]

[tex]\[ [\text{Sn}^{2+}] \approx 3.3 \times 10^{45} \, \text{M} \][/tex]

Therefore, the concentration of [tex]\(Sn^{2+}\)[/tex] is approximately [tex]\(3.3 \times 10^{-2} \, \text{M}\)[/tex].

Answer:

4) Each cytochrome has an iron‑containing heme group that accepts electrons and then donates the electrons to a more electronegative substance.

Explanation:

The cytochromes are proteins that contain heme prosthetic groups. Cytochromes undergo oxidation and reduction through loss or gain of a single electron by the iron atom in the heme of the cytochrome:

[tex]Cytochrome-Fe²⁺ ⇄ cytochrome-Fe³⁺-e⁻[/tex]

The reduced form of ubiquinone (QH₂), an extraordinarily mobile transporter, transfers electrons to cytochrome reductase, a complex that contains cytochromes b and c₁, and a Fe-S center. This second complex reduces cytochrome c, a water-soluble membrane peripheral protein. Cytochrome c, like ubiquinone (Q), is a mobile electron transporter, which is transferred to cytochrome oxidase. This third complex contains the cytochromes a, a₃ and two copper ions. Heme iron and a copper ion of this oxidase transfer electrons to O₂, as the last acceptor, to form water.

Each transporter "downstream" is more electronegative than its neighbor "upstream"; oxygen is located in the inferior part of the chain. Thus, the electrons fall in an energetic gradient in the electron chain transport to a more stable localization in the electronegative oxygen atom.

Answer:

The correct option is: C. form stable hydrogen-bonded dimers

Explanation:

Boiling point is the temperature at which a particular substance changes from liquid state to vapor state.

The boiling point of a chemical substance depends upon the intermolecular forces present between the molecules.

Carboxylic acids are the organic molecules containing carboxyl functional group (COOH). They tend to have greater boiling point than alcohols, ketones, or aldehydes.

This is because only carboxylic acids are capable of forming dimers that are stabilized by hydrogen bonding.

Answer : The final concentration of KOH, HF and KF are 0 M, 1.0 M and 1.0 M respectively.

Explanation :

The given chemical reaction is:

                      [tex]HF(aq)+KOH(aq)\rightarrow KF(aq)+H_2O(l)[/tex]

Initial conc.   2.0 M       1.0 M            0 M

Final conc.    1.0 M         0 M             1.0 M

When 1.0 M of KOH react with 2.0 M HF  then 1.0 M KOH will react with 1.0 M HF to form 1.0 M KF and 1.0 M HF remain unreacted.

So, the final solution contains 1.0 M HF and 1.0 M KF that means the solution contains equal amount of weak acid and salt.

Therefore, the final concentration of KOH, HF and KF are 0 M, 1.0 M and 1.0 M respectively.

The final concentration of KOH, HF and KF are 0 M, 1.0 M and 1.0 M respectively.

HF ( aq ) + KOH ( aq ) ⟶ KF ( aq ) + H₂O ( l )

Initial conc.   2.0 M       1.0 M            0 M

Final conc.    1.0 M         0 M             1.0 M

When 1.0 M of KOH react with 2.0 M HF then 1.0 M KOH will react with 1.0 M HF to form 1.0 M KF and 1.0 M HF remain unreacted. So, the final solution contains 1.0 M HF and 1.0 M KF that means the solution contains equal amount of weak acid and salt.

Therefore, the final concentration of KOH, HF and KF are 0 M, 1.0 M and 1.0 M respectively.

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Answer:

We would expect to form 7.35 moles of grignard reagent.

Explanation:

Step 1: Data given

Mass of magnesium = 210.14 grams

Volume bromobenzene = 772 mL

Density of bromobenzene = 1.495 g/mL

Molar mass of Mg = 24.3 g/mol

Molar mass of bromobenzene = 157.01 g/mol

Step 2: The balanced equation

C6H5Br + Mg ⇒ C6H5MgBr

Step 3: Calculate mass of bromobenzene

Mass bromobenzene = density bromobenzene * volume

Mass bromobenzene = 1.495 g/mL * 772 mL

Mass bromobenzene = 1154.14 grams

Step 4: Calculate number of moles bromobenzene

Moles bromobenzene = mass bromobenzene / molar mass bromobenzene

Moles bromobenzene = 1154.14g / 157.01 g/mol

Moles bromobenzene = 7.35 moles

Step 5: Calculate moles of Mg

Moles Mg = 210.14 grams /24.3 g/mol

Moles Mg = 8.65 moles

Step 6: The limiting reactant

The mole ratio is 1:1 So the bromobenzene has the smallest amount of moles, so it's the limiting reactant. It will be completely consumed ( 7.35 moles). Magnesium is in excess, There will react 7.35 moles. There will remain 8.65 - 7.35 = 1.30 moles

Step 7: Calculate moles of phenylmagnesium bromide

For 1 mole of bromobenzene, we need 1 mole of Mg to produce 1 mole of phenylmagnesium bromide

For 7.35 moles bromobenzene, we have 7.35 moles phenylmagnesium bromide

We would expect to form 7.35 moles of grignard reagent.

In "condensed structural formula" each carbon atom and its attached hydrogen atoms are written in group in the linear form is correct about organic chemistry.

Option B

Explanation:

"condensed structural formula" is a method of writing or presenting organic structures in line of text. It presents all the atoms, but excludes the vertical bonds and all the horizontal single bonds. In condensed structural formula, or we can say semi-structural formula, covalent bonds are not always presented or shown. When the formula or representation is written in line with covalent bonds being shown, then it is referred to as linear formula. For example- the condensed structural formulas of ethane, propane, and ethanol is written as follows:-  

[tex]\mathrm{CH}_{3} \mathrm{CH}_{3},\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{3},\text { and } \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}[/tex]

Apart from these Statement, all others are false because they do not have any logic with respect to organic chemistry.

The correct statement about organic chemistry is:  Alkanes are a type of organic compound that have at least one multiple bond between two carbon atoms.

The correct answer is option C.

a. Organic compounds typically contain carbon and hydrogen, but they can also include other elements like oxygen, nitrogen, sulfur, and more. So, the word "only" in this statement is incorrect.

b. In a condensed structural formula, each carbon atom and its attached hydrogen atoms are typically written as a group, but the arrangement isn't necessarily linear. It represents a simplified way to depict the structure of organic compounds, but the linear form is not a strict requirement. The statement is generally correct but could be misleading due to the term "linear."

c. Alkanes are a type of organic compound that consists of single bonds between carbon atoms, not multiple bonds. The statement is correct.

d. Conformations in organic chemistry refer to the different three-dimensional arrangements of atoms or groups around single bonds, such as in alkanes. The statement is incorrect because it mistakenly refers to the "double bond," which is not characteristic of alkanes.

In summary, statement (c) is the correct one. Alkanes are indeed organic compounds with only single bonds between carbon atoms. The other statements have minor inaccuracies or incorrect terms that make them less precise or entirely incorrect.

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