A heat pump is used to heat a house in the winter and to cool it in the summer. During the winter, the outside air serves as a low-temperature heat source; during the summer, it acts as a high-temperature heat sink. The heat-transfer rate through the walls and roof of the house is 0.75 kJ s—l for each C of temperature difference between the inside and outside of the house, summer and winter. The heat-pump motor is rated at 1.5 kW. Determine the minimum outside temperature for which the house can be maintained at 200C during the winter and the maximum outside temperature for which the house can be maintained at 250C during the summer.

Answer:

b) C = 0.50 J/(g°C)

Explanation:

∴ Q = 50 J

∴ m = 10.0 g

∴ ΔT = 35 - 25 = 10 °C

specific heat (C) :

⇒ C = Q / mΔT

⇒ C = 50 J / (10.0 g)(10 °C)

⇒ C = 0.50 J/(g°C)

Answer:

Kp = 3.62 x 10 ^ -2  

Explanation:

The relationship between Kc and Kp is given as:

Kp =  Kc (RT) ^ Δn -------- (1)

Where:

Kp = Equilibrium Constant in terms of Molar concentrations = 61

Kc = Equilibrium Constant in terms of Partial Pressures

R = Gas Constant = 0.0821 litre.atm/mole.K

Δn = (Total No. of moles of products) - (Total No. of moles of reactants)

Δn = (2) - (3+1) = -2

T = Temperature (K) = 500 K

Substituting all values in equation (1), we get,

Kp = 61 x [ 0.0821 x 500 ] ^ (-2)

Kp = 3.62 x 10 ^ -2  

The study of chemicals and bonds is called chemistry. There are two types of elements are there are these are metals and nonmetals.

The correct answer is Kp = [tex]3.62 * 10^{-2[/tex]

The relationship between Kc and Kp is given as:

Kp =  Kc (RT)^Δn -------- (1)

Where:

Δn = (2) - (3+1) = -2

Substituting all values in equation (1), we get,

[tex]Kp = 61 * [ 0.0821 * 500 ]^{-2Kp = 3.62*10^{-2[/tex]

Hence, the correct answer is [tex]Kp = 3.62*10^{-2[/tex].

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Answer:

Separated

Explanation:

Stan does not feel he identifies closely with the group. He feels the other members are close knit with each other but he is not part of the group.

For Stan, it would be an illusion to say he has a close relationship with the members of the group

This infers that Stan has a separated self-schema with respect to the group.

Answer:

The average diameter of a helium atom is smaller.

Explanation:

Step 1: Data given

An atom gets larger as the number of electronic shells increase; therefore the radius of atoms increases as you go down a certain group in the periodic table of elements.

In general, the size of an atom will decrease as you move from left to the right of a certain period.

Step 2:

Since hydrogen is more left on the periodic table than helium, the diameter of the atom will decrease moving from hydrogen to helium.

Hydrogen has a bigger diameter than helium.

The average diameter of a helium atom is smaller.

Answer:

The mol fraction of cyclohexane in the liquid phase is 0.368

Explanation:

Step 1: Data given

Mass of cyclohexane = 25.0 grams

Mass of 2-methylpentane = 44.0 grams

Temperature = 35.0 °C

The pressure of cyclohexane = 150 torr

The pressure of 2-methylpentane = 313 torr

The pressure we only need for the mole fraction in gas phase.

Step 2: Calculate moles of cyclohexane

Moles cyclohexane = mass cyclohexane / molar mass

Moles cyclohexane = 25.0 g / 84 g/mol = 0.298 mol of cyclohexane

Step 3: Calculate moles of 2-methylpentane

Moles = 44.0 grams / 86 g/mol = 0.512 mol of 2-methylpentane

Step 4: Calculate mole fraction of cyclohexane in the liquid phase

Mole fraction of C6H12:

0.298 / (0.298 + 0.512) = 0.368

The mol fraction of cyclohexane in the liquid phase is 0.368

The mole fraction of cyclohexane in the liquid phase is 36.8%.

To find the mole fraction of cyclohexane in the liquid phase, we need to calculate the total moles of cyclohexane and 2-methylpentane in the mixture. First, we calculate the moles of each component using their molar masses:

moles of cyclohexane = 25 g / 84.18 g/mol = 0.297 mol

moles of 2-methylpentane = 44 g / 86.18 g/mol = 0.509 mol

Next, we calculate the mole fraction of cyclohexane:

mole fraction of cyclohexane = moles of cyclohexane / (moles of cyclohexane + moles of 2-methylpentane)

mole fraction of cyclohexane = 0.297 mol / (0.297 mol + 0.509 mol) = 0.368 or 36.8%

Answer: The redox reactions that occur spontaneously are Reaction W and Reaction Z.

Explanation:

For the reaction to be spontaneous, the Gibbs free energy of the reaction must come out to be negative.

Relationship between standard Gibbs free energy and standard electrode potential follows:

[tex]\Delta G^o=-nFE^o_{cell}[/tex]

For a reaction to be spontaneous, the standard electrode potential must be positive.

To calculate the [tex]E^o_{cell}[/tex] of the reaction, we use the equation:

[tex]E^o_{cell}=E^o_{cathode}-E^o_{anode}[/tex]       .......(1)

Substance getting oxidized always act as anode and the one getting reduced always act as cathode.

The chemical reaction follows:

[tex]2Al(s)+3Pb^{2+}(aq.)\rightarrow 2Al^{3+}(aq.)+3Pb(s)[/tex]

We know that:

[tex]E^o_{Al^{3+}/Al}=-1.66V\\E^o_{Pb^{2+}/Pb}=-0.13V[/tex]

Calculating the [tex]E^o_{cell}[/tex] using equation 1, we get:

[tex]E^o_{cell}=-0.13-(-1.66)=1.53V[/tex]

As, the standard electrode potential is coming out to be positive. So, the reaction is spontaneous.

The chemical reaction follows:

[tex]Fe(s)+Cr^{3+}(aq.)\rightarrow Fe^{3+}(aq.)+Cr(s)[/tex]

We know that:

[tex]E^o_{Fe^{3+}/Fe}=0.77V\\E^o_{Cr^{3+}/Cr}=-0.74V[/tex]

Calculating the [tex]E^o_{cell}[/tex] using equation 1, we get:

[tex]E^o_{cell}=-0.74-(0.77)=-1.51V[/tex]

As, the standard electrode potential is coming out to be negative. So, the reaction is not spontaneous.

The chemical reaction follows:

[tex]Zn(s)+Ca^{2+}(aq.)\rightarrow Zn^{2+}(aq.)+Ca(s)[/tex]

We know that:

[tex]E^o_{Ca^{2+}/Ca}=-2.87V\\E^o_{Zn^{2+}/Zn}=-0.76V[/tex]

Calculating the [tex]E^o_{cell}[/tex] using equation 1, we get:

[tex]E^o_{cell}=-2.87-(-0.76)=-2.11V[/tex]

As, the standard electrode potential is coming out to be negative. So, the reaction is not spontaneous.

The chemical reaction follows:

[tex]Co(s)+2Cu^{+}(aq.)\rightarrow Co^{2+}(aq.)+2Cu(s)[/tex]

We know that:

[tex]E^o_{Cu^{+}/Cu}=0.34V\\E^o_{Co^{2+}/Co}=-0.28V[/tex]

Calculating the [tex]E^o_{cell}[/tex] using equation 1, we get:

[tex]E^o_{cell}=0.34-(-0.28)=0.62V[/tex]

As, the standard electrode potential is coming out to be positive. So, the reaction is spontaneous.

Hence, the redox reactions that occur spontaneously are Reaction W and Reaction Z.

Answer:

Mole fraction: A =  8.70%, B = 37.00%, C =  19.60%, D = 34.80%

K = 6.86

Standard reaction free energy change: -4.77 kJ/mol

Explanation:

Let's do an equilibrium chart for the reaction:

2A + B ⇄ 3C + 2D

1.00  2.00  0     1.00    Initial

-2x     -x     +3x   +2x    Reacts (stoichiometry is 2:1:3:2)

1-2x    2-x    3x    1+2x  Equilibrium

3x = 0.9

x = 0.3 mol

Thus, the number of moles of each one at the equilibrium is:

A = 1 - 2*0.3 = 0.4 mol

B = 2 - 0.3 = 1.7 mol

C = 0.9 mol

D = 1 + 2*0.3 = 1.6 mol

The molar fraction is the mol of the component divided by the total number of moles (0.4 + 1.7 + 0.9 + 1.6 = 4.6 mol):

A = 0.4/4.6 = 0.087 = 8.70%

B = 1.7/4.6 = 0.37 = 37.00%

C = 0.9/4.6 = 0.196 = 19.60%

D = 1.6/4.6 = 0.348 = 34.80%

The equilibrium constant is the multiplication of the concentration of the products elevated by their coefficients, divided by the multiplication of the concentration of the reactants elevated by their coefficients. Because the volume remains constant, we can use the number of moles:

K = (nC³*nD²)/(nA²*nB)

K = (0.9³ * 1.6²)/(0.4² * 1.7)

K = 6.86

The standard reaction free energy change can be calculated by:

ΔG° = -RTlnK

Where R is the gas constant (8.314 J/mol.K), and T is the temperature (25°C = 298 K)

ΔG° = -8.314*298*ln6.86

ΔG° = -4772.8 J/mol

ΔG° = -4.77 kJ/mol

The Mole fraction: A is = 8.70%, B = 37.00%, C = 19.60%, D = 34.80%

K is = 6.86

Then, The Standard reaction free energy change: -4.77 kJ/mol

Now, Let's do an equilibrium chart for the reaction:

Then, 2A + B ⇄ 3C + 2D

1.00  2.00  0     1.00    Initial

After that, -2x     -x     +3x   +2x    Reacts (stoichiometry is 2:1:3:2)

1-2x    2-x    3x    1+2x  Equilibrium

Then, 3x = 0.9

x = 0.3 mol

Thus, When the number of moles of each one at the equilibrium is:

A is = 1 - 2*0.3 = 0.4 mol

B is = 2 - 0.3 = 1.7 mol

C is = 0.9 mol

D is = 1 + 2*0.3 = 1.6 mol

When The molar fraction is the mol of the component divided by the total number of moles (0.4 + 1.7 + 0.9 + 1.6 = 4.6 mol):

A is = 0.4/4.6 = 0.087 = 8.70%

B is = 1.7/4.6 = 0.37 = 37.00%

C is = 0.9/4.6 = 0.196 = 19.60%

D is = 1.6/4.6 = 0.348 = 34.80%

When The equilibrium constant is the multiplication of the concentration of the products elevated by their coefficients, Also divided by the multiplication of the concentration of the reactants elevated by their coefficients.

Because When the volume remains constant, we can use the number of moles:

K is = (nC³*nD²)/(nA²*nB)

K is = (0.9³ * 1.6²)/(0.4² * 1.7)

K is = 6.86

When The standard reaction free energy change can be calculated by:

Then, ΔG° = -RTlnK

Where R is the gas constant (8.314 J/mol.K), and T is the temperature (25°C = 298 K)

After that, ΔG° = -8.314*298*ln6.86

Then, ΔG° = -4772.8 J/mol

Therefore, ΔG° = -4.77 kJ/mol

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Answer:

K remains the same;

Q < K;

The reaction must run in the forward direction to reestablish the equilibrium;

The concentration of [tex]PCl_3[/tex] will decrease.

Explanation:

In this problem, we're adding an excess of a reactant, chlorine gas, to a system that is already at equilibrium. According to the principle of Le Chatelier, when a system at equilibrium is disturbed, the equilibrium shifts toward the side of the equilibrium that minimizes the disturbance.

Since we'll have an excess of chlorine, the system will try to reduce that excess by shifting the equilibrium to the right. Therefore, the reaction must run in the forward direction to reestablish the equilibrium.

The value of K remains the same, as it's only temperature-dependent, while the value of Q will be lower than K, that is, Q < K, as Q < K is the case when reaction proceeds to the right.

As a result, since [tex]PCl_3[/tex] is also a reactant, its concentration will decrease.

Answer:

Empirical C5H3

Molecular

C20H12

Explanation:

Like all other hydrocarbons, benzopyrene would burn in oxygen or air to form carbon iv oxide and water only.

From the mass of carbon iv oxide produced, we can get the mass of carbon and hence the mass of hydrogen.

It can be seen from the question that 12.73mg of carbon iv oxide was produced. Let us convert this to grammes, we simply divide by 1000 = 0.01273g

Now we need to calculate the number of moles of carbon iv oxide produced. To do this, we simply divide the mass by the molar mass of carbon iv oxide. The molar mass of carbon iv oxide is 44g/mol

The number of moles is thus 0.01273/44 = 0.00028392moles

As we can see that there is only one atom of carbon in a molecule of carbon iv oxide. Hence, the number of moles of carbon iv oxide present is equal to 0.00028392moles

From here we can get the mass of carbon which is equal to the number of moles of carbon multiplied by the atomic mass of carbon. The atomic mass of carbon is 12 a.m.u

The mass of carbon in the benzopyrene is thus 0.00028392 * 12 = 0.003472g

The mass of hydrogen in the compound is 0.003649g - 0.003472g = 0.000177g

We can now deduce the empirical formula by dividing the masses by the atomic masses.

H = 0.000177/1 = 0.000177

C = 0.003572/12 = 0.000289333333

We now divide by the smallest which is that of hydrogen.

H = 0.000177/0.000177= 1

C = 0.000289333333/0.000177 = apprx 1.63

Multiply both by 3 to yield C5H3

The molecular formula is as follows:

[(12* 5) + ( 3 * 1)]n = 252.3

63n = 252.3

n = 4

The molecular formula is thus C20H12

Answer:

a. kc = 1,67x10⁶

b. kc = 1,17x10⁷

c. Drug B is the better choice.

Explanation:

The bind of drug-protein is described as:

Protein + Drug ⇄ Drug-protein

Where kc is:

kc = [Drug-protein] / [Protein] [Drug] (1)

a. For A, the equilibrium concentration of each specie is:

[Protein]: 1,60x10⁻⁶M - x

[Drug]: 2,00x10⁻⁶M - x

[Drug-protein]: x = 1,00x10⁻⁶M

-Where x is reaction coordinate-

Thus:

[Protein]: 1,60x10⁻⁶M - 1,00x10⁻⁶M = 0,60x10⁻⁶M

[Drug]: 2,00x10⁻⁶M - 1,00x10⁻⁶M = 1,00x10⁻⁶M

Replacing in (1):

kc = [1,00x10⁻⁶] / [1,00x10⁻⁶] [0,60x10⁻⁶]

kc = 1,67x10⁶

b. For B:

[Protein]: 1,60x10⁻⁶M - x

[Drug]: 2,00x10⁻⁶M - x

[Drug-protein]: x = 1,40x10⁻⁶M

-Where x is reaction coordinate-

Thus:

[Protein]: 1,60x10⁻⁶M - 1,40x10⁻⁶M = 0,20x10⁻⁶M

[Drug]: 2,00x10⁻⁶M - 1,40x10⁻⁶M = 0,60x10⁻⁶M

Replacing in (1):

kc = [1,40x10⁻⁶] / [0,20x10⁻⁶] [0,60x10⁻⁶]

kc = 1,17x10⁷

c. The drug with the bigger kc will be the more effective because will be the drug that binds more strongly with the protein. Thus, drug B is the better choice.

I hope it helps!

The Kc values for the A-protein and B-protein binding reactions are 3.125 and 4.375, respectively. Drug B, which has the higher Kc value, is the better choice for further research as it binds more strongly to the protein.

a. To calculate the Kc value for the A-protein binding reaction, we need to use the equilibrium concentrations of drug A and the A-protein complex. The Kc value is given by [A-protein complex] / ([A] * [protein]). Plugging in the values, we get Kc = (1.00×10^6) / ((2.00×10^6) * (1.60×10^−6)) = 3.125.

b. Similarly, to calculate the Kc value for the B-protein binding reaction, we use the equilibrium concentrations. Kc = (1.40×10^6) / ((2.00×10^6) * (1.60×10^−6)) = 4.375.

c. The drug that binds more strongly will form a higher concentration of drug-protein complex at equilibrium, indicating greater efficacy. In this case, drug B has a higher Kc value, suggesting that it binds more strongly and would be a better choice for further research.

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Answer:

A

Explanation:

Iron has the ground state electronic configuration [Ar]3d64s2

Fe2+ has the electronic configuration [Ar]3d6.

In an octahedral crystal field, there are two sets of degenerate orbitals; the lower lying three t2g orbitals, and the higher level two degenerate eg orbitals. Strong field ligands cause high octahedral crystal field splitting, there by separating the two sets of degenerate orbitals by a tremendous amount of energy. This energy is much greater than the pairing energy required to pair the six electrons in three degenerate orbitals. Since CN- is a strong field ligand, it leads to pairing of six electrons in three degenerate orbitals

The Fe(CN)64- ion is diamagnetic due to the significant energy difference caused by strong field ligands like CN-, resulting in pairing of electrons in the 3 low energy d orbitals before filling the higher energy ones.

The answer is A. There are 3 low lying d orbitals, which will be filled with 6 electrons before filling the 2, assumed to be degenerate, higher energy orbitals. When a metal ion is coordinated to ligands, such as in Fe(CN)64-, the degeneracy of the 3d orbitals is broken (they have different energies), due to the electrostatic interactions between the ligands and the orbitals. In the case of strong-field ligands like CN-, the energy difference is significant enough to cause pairing of electrons in the 3 low energy d orbitals before the 2 high energy orbitals are populated, resulting in a diamagnetic species.

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a)Exothermic

b) it goes up

c) The piston must move out

d)The energy is released by the system

e)ΔE = -616 kJ

Explanation:

sign convention for heat flow:

if the heat flows into the system it is marked with positive sign

when the heat flows out the system it is marked with negative sign

sign convention for work

if work is done on the system it is marked positive

if work is done by the system it is marked negative

sign convention for internal energy

if energy absorbed by system mark positive

if energy released by system mark negative

a)

the heat flow flowing out of the system (q= -300 kJ)

thus the reaction is Exothermic

b)

In exothermic reaction, heat flows from the system to surroundings.

surrounding here is water bath.

As the system is exothermic, hence the temperature of water bath goes up

c)

It is given that 316 kJ of work is done by the system, applying expansion.

To maintain constant pressure of 1 atm the decreased pressure can be compensated with an increase on volume . To increase volume the piston must move out

d)

According to 1st law of thermodynamics,

ΔE =q +w            ⇒1

here,

ΔE = q +w  

ΔE =  -300 kJ -316 kJ

ΔE = -616 kJ          ⇒2

the negative sign denotes the energy is released by the system

e)

from ΔE = -616 kJ   the amount of energy released by the reaction is ΔE = -616kJ  

The concentration of free Ag+ ions at equilibrium is calculated by assuming full complexation of Ag+ with CN- due to a large formation constant, and then considering any small dissociation of the complex back to Ag+ and CN-. The exact concentration can be determined by applying the formation constant for the complex, which is not provided here.

To calculate the concentration of free Ag+ ions at equilibrium in a silver plating operation, we need to consider the following reaction:

Ag+(aq) + 2 CN-(aq) \<--> Ag(CN)2-(aq)

First, we determine the initial concentrations of Ag+ and CN-. AgNO3 completely dissociates in water, so the initial concentration of Ag+ is 0.21 M in 90.0 L. NaCN also dissociates completely, providing 5.0 M of CN- ion in 9.0 L.

Mixing the solutions, we have a total volume of 99.0 L (90.0 L + 9.0 L). The concentration of CN- is calculated as follows:

(5.0 M)(9.0 L) / 99.0 L = 0.4545 M

Since the formation constant (Kf) of the Ag(CN)2- complex is large, we can assume that all the Ag+ will react to form the complex, leaving a negligible concentration of free Ag+ ions. Any remaining CN- ions will affect the equilibrium concentration of free Ag+ ions due to the shift in reaction to the left, as described by Le Chatelier's principle.

We assume that essentially all 0.21 M of the Ag+ ion forms the complex. To find the equilibrium concentration of Ag+, we use the dissociation of the complex, simplified by assuming that the dissociation is so small that it's negligible compared to the remaining CN- concentration.

Since we do not have the exact Kf value provided here, we would normally express the equilibrium concentration of Ag+ in terms of Kf and the concentration of remaining CN-, but to give an exact numerical answer, the specific Kf value for the Ag(CN)2- complex is required from a reliable source like a textbook or scientific database.

Explanation:

It is known that,

       No. of moles = Concentration × volume

As 5 ml of 2.08 M NaCl NaS added to 95 ml of serum then,

        Total volume = (95 + 5) ml = 100 ml

Therefore, total moles of [tex]Na^{+}[/tex] = (5 × 2.08) + (95 × x)

where,      x =  concentration of [tex]Na^{+}[/tex] in original serum

Hence, signal obtained for this NaS = 7.8 mV

Let us assume same volume, that is, 100 ml Serum then [tex]Na^{+}[/tex] will be (100 × x) mol.

Signal obtained for this is 4.27 mV.

Now, the ratio of signal is equal to the ratio of mole.

So,   [tex]\frac{4.27}{7.98} = \frac{100x}{(5 \times 2.08) + 95x}[/tex]

                           x = 0.113

Thus, we can conclude that original concentration of [tex]Na^{+}[/tex] in Serum is 0.113.

The original concentration of Na+ in serum is found by using the provided signals before and after spiking with NaCl, identifying the change in signal due to added Na+, and back-calculating to find the initial Na+ level in serum. The calculation reveals that the original concentration of Na+ is approximately 0.126 M.

To find the original concentration of Na+ in serum, we use the information provided by the atomic emission analysis before and after spiking the serum with a known amount of NaCl. We are given that the unspiked serum produced a signal of 4.27 mV and the spiked serum produced a signal of 7.98 mV after adding 5 mL of 2.08 M NaCl to 95.0 mL of serum.

Step 1: Calculate the moles of Na+ added from the NaCl solution.
Moles of NaCl = 2.08 mol/L × 0.005 L = 0.0104 mol

Step 2: Since the reaction of NaCl in water leads to one mole of Na+ for every mole of NaCl, moles of Na+ added = 0.0104 mol.

Step 3: Calculate the increase in signal due to the added Na+.

Signal increase = 7.98 mV - 4.27 mV = 3.71 mV

Step 4: Determine the signal per mole of Na+ added.

Signal per mole = 3.71 mV / 0.0104 mol = 356.73 mV/mol

Step 5: Calculate the original moles of Na+ in serum from its signal.
Moles of Na+ in serum = 4.27 mV / 356.73 mV/mol = 0.01196 mol

Step 6: Calculate the concentration of Na+ using the serum volume.
Concentration of Na+ = 0.01196 mol / 0.095 L = 0.126 mol/L

The original concentration of Na+ in serum is approximately 0.126 M.

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Answer:  B. you will need 53.2 g Cl2 for complete reaction and will produce 66.7 g of AlCl3.

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.

To calculate the moles, we use the equation:

[tex]\text{Number of moles of aluminium}=\frac{\text{Given mass}}{\text {Molar mass}}=\frac{13.5g}{27g/mol}=0.5moles[/tex]

The balanced reaction is:

[tex]2Al+3Cl_2(g)\rightarrow 2AlCl_3[/tex]

2 moles of aluminium react with= 3 moles of chlorine

Thus 0.5 moles of aluminium react with=[tex]\frac{3}{2}\times 0.5=0.75[/tex]  moles of chlorine

Mass of chlorine=[tex]moles\times {\text{Molar Mass}}=0.75\times 71=53.2g[/tex]

2 moles of aluminium produce = 2 moles of aluminium chloride

Thus 0.5 moles of aluminium react with=[tex]\frac{2}{2}\times 0.5=0.5[/tex]  moles of aluminium chloride

Mass of aluminium chloride=[tex]moles\times {\text{Molar Mass}}=0.5\times 133.34=66.7g[/tex]

Thus 53.2 g of chlorine is used and 66.7 g of  aluminium chloride is produced.

Answer:

The mass fraction of ferric oxide in the original sample :[tex]\frac{723}{3110}[/tex]

Explanation:

Mass of the mixture = 3.110 g

Mass of [tex]Fe_2O_3=x[/tex]

Mass of [tex]Al_2O_3=y[/tex]

After heating the mixture it allowed to react with hydrogen gas in which all the ferric oxide reacted to form metallic iron and water vapors where as aluminum oxide did not react.

[tex]Fe_2O_3(s)+3H_2(g)\rightarrow 2Fe(s)+3H_2O(g)[/tex]

Mass of mixture left after all the ferric oxide has reacted = 2.387 g

Mass of mixture left after all the ferric oxide has reacted = y

[tex]x=3.110 g- y=3.110 g - 2.387 g = 0.723 g[/tex]

The mass fraction of ferric oxide in the original sample :

[tex]\frac{0.723 g}{3.110 g}=\frac{723}{3110}[/tex]

To find the missing equilibrium constant, we can use stoichiometry and the first given equilibrium constant. The missing equilibrium constant for the second reaction is the square of the given Kc value.

To determine the missing equilibrium constant, you can use the concept of equilibrium constant expressions.

In the first reaction, 2 HD(g) ⇌ H2(g) + D2(g), the equilibrium constant is given as Kc = 0.28.

To find the value of the missing equilibrium constant for the second reaction, 2 H2(g) + 2 D2(g) ⇌ 4 HD(g), we can use the stoichiometry.

Since the equilibrium constant is a ratio of product concentrations to reactant concentrations, and the stoichiometric coefficients for the second reaction are all multiplied by 2 compared to the first reaction, the missing equilibrium constant would be the square of the given Kc value.

Therefore, the missing equilibrium constant is 0.28 squared, which is approximately 0.0784.

The equilibrium constant for the reaction 2 H₂(g) + 2 D₂(g) ⇌ 4 HD(g) is D) 13

To determine the equilibrium constant for the reaction 2 H₂(g) + 2 D₂(g) ⇌ 4 HD(g) given the equilibrium constant for the reverse reaction, 2 HD(g) ⇌ H₂(g) + D₂(g), which is Kc = 0.28, we can use the concept that the equilibrium constant for the reverse reaction is the reciprocal of the equilibrium constant for the forward reaction.

The given reaction is:

2 HD(g) ⇌ H₂(g) + D₂(g), Kc = 0.28

The reverse reaction is:

H₂(g) + D₂(g) ⇌ 2 HD(g), K'c = 1 / 0.28

K'c = 3.57

The target reaction is twice the reverse reaction:

2 H₂(g) + 2 H₂(g) ⇌ 4 HD(g)

When the reaction coefficients are doubled, the equilibrium constant is squared:

Kc = K'c²

Kc = 3.57² = 12.75

Therefore, the equilibrium constant for the reaction 2 H₂(g) + 2 D₂(g) ⇌ 4 HD(g) is 12.798

Rounding of to two significant figures, the Equilibrium constant is D) 13

Complete question is - The equilibrium constant is given for one of the reactions below. Determine the value of the missing equilibrium constant.

2 HD (g) = H2 (g) + D2 (g) Kc = 0.28

2 H2 (g) + 2 D2 (g) = 4 HD (g) Kc = ?

A) 7.8 x 10⁻²

B) 3.6

C) 0.53

D) 13

E) 1.9

Answer:

Nitrogen is an example of an element (option B)

Explanation:

Water, glucose and salt are sort of compound.

They are compounds that have certain elements linked by specific bonds.

H₂O - Water

C₆H₁₂O₆ - Glucose

NaCl - Salt

Nitrogen is an example of an element. Unlike water, glucose, and salt, which are compounds, nitrogen exists as a diatomic molecule with the chemical formula N₂.

An example of an element is B) Nitrogen. Nitrogen is a chemical substance that is represented by the symbol N and is found in the air we breathe as a diatomic molecule (N₂).

In the context of other options presented in such questions, water (H₂O) is a compound consisting of hydrogen and oxygen, glucose (C₆HO₆) is a carbohydrate compound, and salt commonly refers to sodium chloride (NaCl), which is also a compound.

Answer:

contains the maximum amount of solute that will dissolve in that solvent at that temperature.

Explanation:

Solution= solute+ solvent

The solubility of a solute depends on temperature. A solution containing just the right (maximum) amount of solute that can normally dissolve at a given temperature is said to be saturated.

A saturated solution contains the maximum amount of solute that dissolves in a solvent at a given temperature. Exceeding the solubility leads to a supersaturated solution and solute precipitation. Solubility varies with temperature.

A saturated solution is one that contains the maximum amount of solute that will dissolve in that solvent at that particular temperature. The solubility of a solute in a particular solvent is the maximum concentration that may be achieved under given conditions when the dissolution process is at equilibrium. In a saturated solution, the solute concentration equals its solubility. If a solute's concentration exceeds its solubility, it forms a supersaturated solution which is an unstable condition and results in solute precipitation when perturbed. The extent to which a substance may be dissolved in water, or any solvent, is quantitatively expressed as its solubility. Solubilities for gaseous solutes decrease with increasing temperature, while those for most, but not all, solid solutes increase with temperature.

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In a chemical reaction, the total mass of reactants is equals to the total mass of the products. Here, A and B react to produce C and D. Given that 21g of A and 22g of B (43g in total) are converted into 17g of C and x grams of D, the mass of D is therefore 43g - 17g = 26g.

The law of conservation of mass states that matter cannot be created or destroyed in a chemical reaction. In your hypothetical reaction, 21g of A and 22g of B react to create C and D. Combined, the reactants have a total mass of 43g. In the product, we have 17g of C and the mass of D which we're trying to find. Now, given that mass of reactants = mass of products, we can say that 43g (total mass of A+B) = 17g (mass of C) + mass of D. By rearranging the equation, we find that mass of D = 43g - 17g = 26g. So, 26g of D will be produced according to the law of conservation of mass.

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Final answer:

Upon decomposition, lithium nitride (Li₃N) breaks down into lithium (Li) and nitrogen (N₂) gas. The balanced chemical equation for this decomposition is 2 Li₃N(s) → 6 Li(s) + N₂(g). This is an example of chemical decomposition in chemistry.

Explanation:

Predicting the products of the decomposition of lithium nitride, Li₃N, involves understanding the reactions of ionic compounds. Lithium nitride is comprised of lithium (Li) ions and nitride (N³⁻) ions. Upon decomposition, lithium nitride would likely break down into its constituent elements, lithium (Li) and nitrogen (N₂). The balanced equation for this decomposition would be: 2 Li₃N(s) → 6 Li(s) + N₂(g)

Here, solid lithium nitride (Li₃N) decomposes into solid lithium (Li) and nitrogen gas (N₂) when subjected to suitable conditions such as heating. This type of reaction demonstrates basic principles of chemical decomposition and stoichiometry in chemistry.

Explanation:

It is known that the atomic number of magnesium is 12 and its electronic distribution is 2, 8, 2. And, in order to attain stability a magnesium atom will tend to lose its valence electrons.

That is, being a metal magnesium atom will lose its 2 valence electrons and hence it forms a [tex]Mg^{2+}[/tex] ion.

Equation for this type of loss is as follows.

                [tex]Mg \rightarrow Mg^{2+} + 2e^{-}[/tex]

Therefore, we can conclude that the charge of the ion formed by the [tex]_{12}Mg[/tex] atom is +2.

Answer:

2.12*10^-4 moles

Explanation:

If 3.03ml contains 1.35*10^-4mol then 7.79 will contain 7.79ml*1.35*10^-4/3.03= 3.47*10^-4 moles

Amount added= (3.47-1.35)*10^-4=2.12*10^-4moles

Answer: 2.12 X 10^-4

Explanation:

First, find the final number of moles of radon in the container after the addition by rearranging Avogadro's law to solve for n2.

n2= V2 × n1 / V1

Substitute the known values ofn1, V1, and V2.

n2 = 7.79 mL × 1.35 × 10^−4 mol / 3.03 mL = 3.47 × 10^−4 mol

Find the difference between the final number of moles (n2) and the initial number of moles (n1).

n2−n1 = 3.47 × 10^-4 mol −1 .35 × 10^−4 mol= 2.12 × 10^−4mol

The radioactive uranium decays to produce thorium and it emits an alpha particle or helium atom. Thus, option A is correct.

Unstable heavy isotopes of elements undergo nuclear decay to produce stable atoms by the emission of charged particle such as alpha or beta particles.

Based on the emitted particle, there are two types of decay process namely alpha decay and beta decay. In alpha decay atoms emits alpha particles which are helium nuclei and the atom losses its mass number by 4 units and atomic number by two units,

In beta decay, electrons are emitted by the atom, where no change occurs in mass number and atomic number increases by one unit. Uranium undergo alpha decay by emitting alpha particle or helium nuclei.

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Answer:

The Emf of the given cell at [Fe2+] = 2.0 M and [Fe3+] = 1.9 M is 0.48 V

Explanation:

The half cell reaction can be written as :

Anode-Half (oxidation) :

[tex]Fe^{2+}\rightarrow Fe^{3+} + 1e^{-}[/tex] ......E = 0.77 V

(multiply this equation by 4 to balance the electrons)

Cathode-half (reduction)

[tex]4H^{+} +O_{2} + 4e^{-} \rightarrow 2H_{2}O[/tex]....E= 1.23 V

[tex]E^{0}_{cell} = E_{cathode} - E_{anode}[/tex]

[tex]E^{0}_{cell} = 1.23 - 0.77[/tex]

[tex]E^{0}_{cell} = 0.46 V[/tex]

According to Nernst Equation

[tex]E_{cell} = E^{0} - \frac{RT}{nF}lnQ[/tex]

[tex]E_{cell} = E^{0} - \frac{0.059}{n}logQ[/tex]

n = number of electron transferred in the cell reaction = 4

The balanced equation is :

[tex]4Fe^{2+} + 4H^{+} +O_{2} \rightarrow 4Fe^{3+} + 2H_{2}O[/tex]

[tex]E_{cell} = 0.46 - \frac{0.059}{4}logQ[/tex]

[tex]log Q = \frac{[Fe^{3+}]^{4}}{[Fe^{2+}]^{4}}[/tex]

[tex]log Q = \left ( \frac{[Fe^{3+}]}{[Fe^{2+}]} \right )^{4}[/tex]

[tex]log Q = \left ( \frac{1.9}{2.0} \right )^{4}[/tex]

Insert the value of log Q in Nernst  Equation:

[tex]E_{cell} = 0.46 - \frac{0.059}{4} log\left ( \frac{1.9}{2.0} \right )^{4}[/tex]

(using :[tex]log^{a}b = a\log b[/tex]

)

[tex]E_{cell} = 0.46 - log\frac{1.9}{2.0}[/tex]

[tex]E_{cell} = 0.46 - log(0.95)[/tex]

[tex]E_{cell} = 0.46 -(-0.0227)[/tex]

[tex]E_{cell} = 0.482 V[/tex]

The cell EMF is obtained from Nernst equation as 0.451 V.

The reaction equation is given by;

4Fe2+ (aq) + O2(g) + 4H+ (aq)-------->4Fe3+(aq)+2H2O(l)

We have the following information;

EMF under standard conditions = 0.46 V

[Fe2+]= 2.0M

[Fe3+]= 1.9 M

From Nernst equation;

Ecell = E°cell - 0.0592/n logQ

Where;

E°cell = 0.46 V

n = 4

Q =  [Fe3+]^4/ [Fe2+]^4

Q = [1.9]^4/[2.0]^4

Q = 0.8

Substituting values;

Ecell =  0.46 - 0.0592/4 log (0.8)

Ecell = 0.451 V

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Answer:

Option B

Explanation:

Energy required to remove outermost electron from an neutral atom is called ionization energy or first ionization energy ([tex]IE_1[/tex])

Energy required to remove an electron from M+ ion is called second ionization energy ([tex]IE_2[/tex]).

Energy required to remove an electron from M2+ ion is called third ionization energy [tex]IE_2[/tex]).

Therefore, among the given options:

[tex]Al+e^- \rightarrow Al^{+}(g),\ IE_1[/tex]

[tex]Al^++e^- \rightarrow Al^{2+}(g),\ IE_2[/tex]

[tex]Al^{2+}+e^- \rightarrow Al^{3+}(g),\ IE_3[/tex]

Therefore, the correct option is b

The third ionization of aluminum refers to the removal of the third electron from an aluminum atom. The correct representation is: B) Al2+ (g) --------> Al3+(g) + e-. This represents the transition from a double positive ion to a triple positive ion of aluminum.

In Chemistry, the ionization energy of an element refers to the energy required to remove an electron from an atom or an ion. The process of ionization occurs in successive stages for each electron removed. When considering the third ionization of aluminum, it implies that two electrons have already been removed, and we're focusing on the removal of a third electron from the resulting ion.

The correct option that represents the third ionization of aluminum is:

B) Al

2+

(g) --------> Al

3+

(g) + e

-

This is because option B represents the transition of aluminum from a double positive ion (Al2+) to a triple positive ion (Al3+) with the removal of an electron.

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Answer:

(a) 0.699 kJ/K

(b) -0.671 kJ/K

(c) 0.028 kJ/K

Explanation:

The Refrigerant-134a flows into the evaporator as a saturated liquid-vapor mixture and flows out as a saturated vapor at a saturation pressure of 160 kPa and temperature of -15.64°C (estimated from the Saturated Refrigerant-134a Temperature Table).

(a) The entropy change of the refrigerant (ΔS[tex]_{R-134a}[/tex]) = Q/T[tex]_{1}[/tex]

Q = 180 kJ

T[tex]_{1}[/tex] = -15.64 + 273.15 = 257.51 K

ΔS[tex]_{R-134a}[/tex] = Q/T[tex]_{1}[/tex] = 180/257.51 = 0.699 kJ/K

(b) The entropy change (ΔS[tex]_{c}[/tex]) of the cooled space (ΔS[tex]_{c}[/tex]) = -Q/T[tex]_{2}[/tex]

Q = -180 kJ

T[tex]_{2}[/tex] = -5 + 273.15 = 268.15 K

ΔS[tex]_{c}[/tex] = Q/T[tex]_{2}[/tex] = -180/268.15 = -0.671 kJ/K

(c) The total entropy change for this process (ΔS[tex]_{t}[/tex]) = ΔS[tex]_{R-134a}[/tex] + ΔS[tex]_{c}[/tex] = 0.699 - 0.671 = 0.028 kJ/K

Answer:

c. Ice, H₂O, has a solid structure with alternating H−O interactions.

e. HF has a higher boiling point than HCl.

Explanation:

For molecules to interact through hydrogen bonding, it is required that there is an H atom bonded to a more electronegative atom, such as N, O or F.

Select the interactions that can be explained by hydrogen bonding. Check all that apply.

a. CH₄ molecules interact more closely in the liquid than in the gas phase.  NO. The electronegativity of C is not high enough to form hydrogen bondings.

b. HF is a weak acid neutralized by NaOH. NO. This reaction occurs in water and it is better explained by ion-ion forces.

c. Ice, H₂O, has a solid structure with alternating H−O interactions. YES. This structure is a consequence of the hydrogen bonding.

d. H₂Te has a higher boiling point than H₂S.  NO. The electronegativities of Te and S are not high enough to form hydrogen bondings.

e. HF has a higher boiling point than HCl. YES. The stronger hydrogen bonding interactions in HF explain the higher boiling point.

Final answer:

Hydrogen bonding explains interactions such as HF being a weak acid, the solid structure of ice (H2O), and the higher boiling point of HF compared to HCl.

Explanation:

In the context of the provided information, the interactions that can be explained by hydrogen bonding are:

Hydrogen bonding occurs when a hydrogen atom is bonded to a highly electronegative atom such as oxygen, nitrogen, or fluorine, creating a strong dipole-dipole interaction.

These interactions are responsible for the higher boiling points and particular properties of substances like water (H2O) and hydrogen fluoride (HF).

Answer:see attached image

Explanation:

In organic chemistry, a product may be kinetically or thermodynamically favoured. A kinetically favours product forms faster, it may not necessarily be the more stable product. The thermodynamically favoured product forms at a slower rate but is more stable. Often times, the kinetically favoured product rearranges itself to form the thermodynamically favoured product at equilibrium. The endo product of the Diels Alder reaction mentioned in the question is first formed (kinetically favoured) but rearranges to form the exo product (thermodynamically favoured) at equilibrium. This is clear shown in the reaction mechanism attached below.

The balanced net ionic equations for the reactions are:

a. Cr2(SO4)3(aq) + 3(NH4)2CO3(aq) → 2Cr(CO3)3(s) + 6NH4NO3(aq),

b. Ba(NO3)2(aq) + K2SO4(aq) → BaSO4(s) + 2KNO3(aq),

c. Fe(NO3)2(aq) + 2KOH(aq) → Fe(OH)2(s) + 2KNO3(aq)

Net ionic equations represent the actual chemical change occurring in a reaction, excluding spectator ions. Examples include the exchange of ions to form water in a neutralization reaction and the formation of precipitates such as calcium phosphate or silver chloride.

Thus, the net balanced ionic equations of given reactions are:

a. Cr2(SO4)3(aq) + 3(NH4)2CO3(aq) → 2Cr(CO3)3(s) + 6NH4NO3(aq)

b. Ba(NO3)2(aq) + K2SO4(aq) → BaSO4(s) + 2KNO3(aq)

c. Fe(NO3)2(aq) + 2KOH(aq) → Fe(OH)2(s) + 2KNO3(aq)