At a certain temperature, the K p for the decomposition of H 2 S is 0.739 . H 2 S ( g ) − ⇀ ↽ − H 2 ( g ) + S ( g ) Initially, only H 2 S is present at a pressure of 0.215 atm in a closed container. What is the total pressure in the container at equilibrium?

Answer:

pH after the addition of 10 ml NaOH = 4.81

pH after the addition of 20.1 ml NaOH = 8.76

pH after the addition of 25 ml NaOH = 8.78

Explanation:

(1)

Moles of butanoic acid initially present = 0.1 x 20 = 2 m moles  = 2 x 10⁻³ moles,

Moles of NaOH added = 10 x 0.1 = 1 x 10⁻³ moles

                          CH₃CH₂CH₂COOH + NaOH ⇄ CH₃CH₂CH₂COONa + H₂O

Initial conc.            2 x 10⁻³                 1 x 10⁻³           0            

Equilibrium             1 x 10⁻³                   0                  1 x 10⁻³

Final volume = 20 + 10 = 30 ml = 0.03 lit

So final concentration of Acid = [tex]\frac{0.001}{0.03} = 0.03mol/lit[/tex]

Final concentration of conjugate base [CH₃CH₂CH₂COONa][tex]=\frac{0.001}{0.03} = 0.03 mol/lit[/tex]

Since a buffer solution is formed which contains the weak butanoic acid and conjugate base of that acid .

Using Henderson Hasselbalch equation to find the pH

[tex]pH=pK_{a}+log\frac{[conjugate base]}{[acid]} \\\\=-log(1.54X10^{-5} )+log\frac{0.03}{0.03} \\\\=4.81[/tex]

During titration of butanoic acid with NaOH, we can calculate the pH at various points using the Henderson-Hasselbalch equation for buffer scenarios. After 10.00mL of NaOH, the pH will be 4.74. After 20.10 mL, the pH will be 8.27, and after 25.00 mL, the pH will be 12.30.

This involves calculating the pH at various stages during a titration procedure. Here the titration involves a weak acid, butanoic acid, with a strong base, NaOH. We can simplify the reaction as follows: CH₃CH₂CH₂COOH + OH- --> CH₃CH₂CH₂COO- + H₂O.

(a) After 10.00 mL of NaOH is added, the system isn't at equivalence. Here, the reaction hasn't fully completed and a buffer solution is present. Using the Henderson-Hasselbalch equation, we can find the pH: pH = pKa + log([base]/[acid]). After calculating, we can find pH = 4.74.

(b) After 20.10 mL NaOH is added, the system reaches past equivalence. The pH can be determined by finding pOH using the remaining OH- concentration and then subtracting from 14. After the calculation, the pH = 8.27.

(c) For 25.00 mL of NaOH, the system is beyond equivalence and extra OH- ions increase pH. The pH calculation is like previous step and the result will be pH = 12.30.

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Answer: Option (b) is the correct answer.

Explanation:

When the student opens up the bottle lid then due to the difference in atmospheric pressure and pressure inside the bottle will lead the carbon dioxide to form more number of bubbles.

Also, when the bottle opens up then tiny bubbles around the neck of bottle will tend to float towards the open surface. Hiss sound appears because on opening the lid of bottle excess gas tends to come out of the bottle causing the sound.

Thus, we can conclude that when the student opens the bottle and hears a loud hiss as gas under pressure escapes from the bottle the bubbles will grow, and more may appear.

When a carbonated soft drink bottle is opened, the decrease in pressure reduces the solubility of CO₂, leading to the formation of more bubbles. Thus, the correct answer is b) The bubbles will grow, and more may appear.

When a carbonated soft drink is in an unopened bottle, it is under high CO₂ pressure. This high pressure keeps a large amount of carbon dioxide dissolved in the liquid. The bubbles seen inside the bottle are carbon dioxide gas clinging to the container. When the bottle is opened, the pressure above the liquid decreases significantly, causing a loud hiss as the gas escapes.

According to Henry's Law, the solubility of a gas in a liquid decreases as the pressure decreases. Consequently, the solubility of CO₂ in the soda is reduced, which means that more dissolved CO₂ will leave the solution and form bubbles. This explains why more bubbles will appear and existing bubbles will grow after opening the bottle.

Answer:

90/38 Sr

Explanation:

Gamma decay involves rearrangements in an atomic nucleus usually following a nuclear change. When a nuclear change occurs, the daughter nuclei is in excited state, a high energy state. The nucleons quickly rearrange themselves and rapidly lower the energy of the daughter nucleus. The corresponding amount of excited state energy is emitted as the daughter nuclei return to ground state as short range, high energy electromagnetic gamma rays.

Hence, the number of nucleons in the nucleus remain the same before and after a gamma decay.

Answer:

4 Sb (+3) +  2 Br (2) O (3) ----> 4 SbBr + 3 O(-2)

In the equation, place the valences in parentheses and the stoichiometric balance numbers so that the reaction is balanced, place them in bold.

Explanation:

In this chemical equation it seems to me that the valences of BrO are wrong.

That is why I will complete the equation, demonstrating the chemical reaction, and also use the appropriate valences.

Assuming that Sb has a valence of +3 and that the Br that appears in the form of oxide with oxygen (valence -2) has a valence of +3 (because -3 does not exist as valence or oxidation state of bromine).

Answer:

Explanation:

pKa = 3.86

-log Ka = pKa

- log Ka = 3.86

Ka = 1 / ( 10^(3.86)) = 1.38 × 10⁻⁴

lactic → (H⁺) + lactate

but Ka ( equilibrium constant ) = ( H⁺) (lactate) / ( lactic acid)

when HCl dissociate, it forms

HCl → H ⁺ + Cl⁻

0.08 M of HCl will yield 0.08 M H⁺, lactate ion = 0.1 M

1.38 × 10⁻⁴ = (0.08) (lactate) / 0.1

(1.38 × 10⁻⁴  × 0.1) / 0.08 = lactate

lactate = 1.73 × 10⁻⁴

Answer:

27.3 kJ/mol

Explanation:

You would use the Arrhenius Equation to solve this problem.

[tex]ln(\frac{k_{2} }{k_{1} } )=\frac{E_{a} }{R} (\frac{1}{T_{1} } -\frac{1}{T_{2} } )[/tex]

Plug the rate constants into k1 and k2.  Plug the temperatures into T1 and T2. R is a constant and is equal to 8.314.  Solve for Ea.

Your answer should be 27,303.03 J/mol or 27.3 kJ/mol.

Hope this helps! <3

The activation energy will be equal to "12.40 kJ/mol". To understand the calculation, check below.

According to the question,

For 1st order, rate constant = 0.060 s⁻¹

Temperature, T₁ = 298 K

                       T₂ = 331 K

Increased rate constant = 0.18s⁻¹

We know the formula,

→ ln k = ln A - [tex]\frac{E_a}{RT}[/tex]

By substituting the rate constant value,

  ln 0.06 = ln A - [tex]\frac{E_a}{298 \ R}[/tex] ...(equation 1)

  ln 0.18 = ln A - [tex]\frac{E_a}{318 \ R}[/tex] ...(equation 2)

From "equation 1 and 2", we get

Activation energy, 1.09 = [tex]\frac{83 \ E_a}{113538 \ R}[/tex]

                                  [tex]E_a[/tex] = 12.40 kJ/mol

Thus the above answer is correct.

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Answer:

The average rate of formation of I₂(g) is 6.00x10⁻⁵Ms⁻¹

Explanation:

The question is:

The average rate of formation of I2 over the same time period is______M s-1.

Based in the reaction:

2 HI(g) ⇄ H₂(g) + I₂(g)

If 2 moles of HI(g) disappears in a rate of 1.20x10⁻⁴Ms⁻¹, 1 mole of  I₂(g) will appears at:

1 mole I₂(g) × (1.20x10⁻⁴Ms⁻¹ / 2 mol) = 6.00x10⁻⁵Ms⁻¹ I₂(g)

Answer:

The correct option is  d isothermal

Explanation:

Step 1: Data given

An adiabatic process is a process in which no heat is gained or lost by the system.

A constant- volume process, also called an isochoric process is a process in which the volume is held constant, meaning that the work done by the system will be zero.

An Isobaric process is a thermodynamic process taking place at constant pressure

An isothermal process is a thermodynamic process, in which the temperature of the system remains constant

Step 2: This situation

The container is slowly compressed, while the temperature is kept constant.

This is  an isothermal process.

The correct option is  d isothermal

Answer:

19,623 J or 19.6 kJ of heat is needed to change ice at 0°C to water at 45°C

Explanation:

To calculate the energy needed to change 37.5g of ice at 0°C to water at 45.0°C, we obtain the individual values of energy needed to convert the ice from 0° to water at 0 °C and the value of energy needed to convert the water from 0 °C to water at 45°C and then add the values together.

Heat (q) = mΔHf + mCpΔT

So;

1. heat needed to change from solid to liquid = m ΔHf

q = 37.5 * 335

q = 12,562.5 Joules

2. heat needed to convert the water at 0C to water at 45 C

q = mcΔT

q= 37.5 * 4.184 * ( 45-0)

q = 37.5 * 4.184 * 45

q = 7,060.5 J

The heat needed to change the ice to water at 45 C = 12, 562.5 + 7.060.5 = 19,623 J or 19.6 kJ of heat.

Answer:

We need 19620 joules

Explanation:

Step 1: Data given

Mass of ice = 37.5 grams

Temperature of ice = 0.00 °C

Final temperature of water = 45.0°C

(Heat of fusion = 335J/g,

Specific heat of liquid water= 4.184J/g°C

Heat of vaporization = 2259 J/g

Step 2: Calculate the energy needed to melt ice to water at 0°C

Q = m*ΔHfus

Q = 37.5 grams * 335J/g

Q = 12562.5 J = 12.56 kJ

Step 3: Calculate energy needed to heat water from 0 to 45 °C

Q = m*c*ΔT

⇒with Q = the enegy needed to heat water from 0 to 45 °C

⇒with m =the mass of water = 37.5 grams

⇒with ΔT = the change of temperature = 45 °C

⇒with c = the specific heat of water = 4.184 J/g°C

Q = 37.5g * 4.184 J/g°C * 45 °C

Q = 7060.5 J = 7.06 kJ

Step 4: Calculate the total heat needed

Total heat = 12.56 kJ + 7.06 kJ

Total heat = 19.62 kJ = 19620 J

We need 19620 joules

Answer:

See explaination

Explanation:

Molar absorptivity, also known as the molar extinction coefficient, is a measure of how well a chemical species absorbs a given wavelength of light.

It is commonly used in chemistry and should not be confused with the extinction coefficient, which is used more often in physics.

Please kindly check attachment for the step by step solution of the given problem.

Answer:

lemon juice

Explanation:

lemons are acidic.

Answer:

the answer is lemon.

Explanation:

Answer:

According to Le Chatelier's principle, increasing the reaction temperature of an exothermic reaction causes a shift to the left and decreasing the reaction temperature causes a shift to the right.

Explanation:

C6H12O6(s) + 6O2(g) ⇌6CO2(g) + 6H2O(g)

We are told that the forward reaction is exothermic, meaning heat is removed from the reacting substance to the surroundings.

According to Le Chatelier's principle,

1. for an exothermic reaction, on increasing the temperature, there is a shift in equilibrium to the left and formation of the product is favoured.

2. if the temperature of the system is decreased, the equilibrium shifts to right and the formation of the reactants is favoured.

3. if the reaction temperature is kept constant, the system is at equilibrium and there is no shift to the right nor to the left.

Answer:

Increasing temperature = balance will shift to the left

Decreasing temperature = balance will shift to the right

Explanation:

Step 1: Data given

The increase or decrease in temperature can have an influence on the position of the equilibrium.

If the temperature is increased, the system will ensure that less heat is released. So the balance will shift to the left.

When the temperature drops, however, the system will produce more heat: the balance will shift to the right.

Step 2: The balanced equation

C6H12O6(s) + 6O2(g) ⇌ 6CO2(g) + 6H2O(g)

This is an endothermic reaction

Step 3: Increasing the temperature

If the temperature were increased, the heat content of the system would increase.

In exothermic reactions, increase in temperature decreases the K value. This means less products will be formed. The balance will shift to the left.

Step 4: Decreasing the temperature

If the temperature were decreased, the heat content of the system would increase.

In exothermic reactions, decrease in temperature increases the K value. This means more products will be formed, less reactants. The balance will shift to the right.

Answer:

1.12 g of oxygen.

Explanation:

First step is to determine the decomposition reaction:

Ammonium perchlorate → NH₄ClO₄

2NH₄ClO₄ (s) →  N₂(g) + Cl₂(g) + 2O₂(g) + 4H₂O(g)

We define the moles of the reactant:

4.1 g . /117.45 g/mol = 0.0349 moles

As ratio is 2:2, If I use 0.0349 moles of perchlorate I would produce the same amount of moles of oxygen.

0.0349 mol of O₂ are produced by the reaction

We convert to mass:  0.0349 mol . 32 g /1mol = 1.12 g

Answer:

Explanation:

During a phase change, the temperature remains constant because the energy supplied via heat is used differently. While not changing states, the heat (energy) goes into changing the kinetic energy of every particle in the body that receives it.

Answer:

Neither of them will neutralize the buffer solution.

Explanation:

The buffer solution of HNO₂ and KNO₂ will be neutralized when the acid reacts and consume all of the base of the buffer solution or when the base added reacts and consume all of the acid of the buffer solution.

First, we need to calculate the number of moles of the acid and the base of the buffer:

[tex] n_{HNO_{2}} = C*V = 0.100 M*0.500 L = 0.050 moles [/tex]

[tex] n_{KNO_{2}} = C*V = 0.150 M*0.500 L = 0.075 moles [/tex]

Now, let's evaluate each case.

A) 250 mg of NaOH:

We need to calculate the number of moles of NaOH

[tex] n_{NaOH} = \frac{m}{M} [/tex]

Where m: is the mass = 250 mg, and M: is the molar mass = 39.99 g/mol  

[tex] n_{NaOH} = \frac{0.250 g}{39.99 g/mol} = 6.25 \cdot 10^{-3} moles [/tex]

The number of moles of the acid HNO₂ after reaction with the base added NaOH is:

[tex] n_{a_{T}} = n_{a} - n_{b} = 0.050 moles - 6.25 \cdot 10^{-3} moles = 0.044 moles [/tex]

After the reaction of HNO₂ with the NaOH remains 0.044 moles of acid, hence, 250 mg of NaOH would not exceed the capacity of the buffer to neutralize it.

B) 350 mg KOH:

The number of moles of KOH is:

[tex]n_{KOH} = \frac{m}{M} = \frac{0.350 g}{56.1056 g/mol} = 6.23 \cdot 10^{-3} moles[/tex]

Now, the number of moles of HNO₂ that remains in the solution is:

[tex] n_{T} = 0.050 moles - 6.23 \cdot 10^{-3} moles = 0.044 moles[/tex]

Therefore, 350 mg of KOH would not exceed the capacity of the buffer to neutralize it.

C) 1.25 g of HBr:

The number of moles of HBr is:

[tex] n_{HBr} = \frac{m}{M} = \frac{1.25 g}{80,9119 g/mol} = 0.015 moles [/tex]

Now, the number of moles of the base KNO₂ that remains in solution after the reaction with HBr is:

[tex] n_{T} = 0.075 moles - 0.015 moles = 0.06 moles [/tex]

Hence, 1.25 g of HBr would not exceed the capacity of the buffer to neutralize it.

D) 1.35 g of HI:

The number of moles of HI is:

[tex] n_{HI} = \frac{m}{M} = \frac{1.35 g}{127.91 g/mol} = 0.0106 moles [/tex]

Now, the number of moles of the base KNO₂ that remains in solution after the reaction with HI is:

[tex] n_{T} = 0.075 moles - 0.0106 moles = 0.0644 moles [/tex]

Hence, 1.35 g of HI would not exceed the capacity of the buffer to neutralize it.

Therefore, neither of them will neutralize the buffer solution.

I hope it helps you!

Part A: No

Part B: Yes

Part C: Yes

Part D: Yes

Part A: To determine if 250 mg of NaOH would exceed the buffer capacity, we first need to calculate the number of moles of NaOH added and compare it to the number of moles of HNO2 in the buffer.

The moles of NaOH added are calculated as follows:

Part A: No

Part B: Yes

Part C: Yes

Part D: Yes

Part A: To determine if 250 mg of NaOH would exceed the buffer capacity, we first need to calculate the number of moles of NaOH added and compare it to the number of moles of HNO2 in the buffer.

 The moles of NaOH added are calculated as follows:

[tex]\[ \text{moles of NaOH} = \frac{\text{mass of NaOH}}{\text{molar mass of NaOH}} = \frac{250 \times 10^{-3} \text{g}}{40.0 \text{g/mol}} = 6.25 \times 10^{-3} \text{mol} \][/tex]

The volume of the buffer solution is 500.0 mL, which is equivalent to 0.500 L. The moles of HNO2 in the buffer are calculated by: [tex]\[ \text{moles of HNO2} = \text{concentration of HNO2} \times \text{volume of buffer} = 0.100 \text{M} \times 0.500 \text{L} = 5.00 \times 10^{-2} \text{mol} \][/tex]

 Since the moles of NaOH added (6.25 × 10^-3 mol) are less than the moles of HNO2 in the buffer (5.00 × 10^-2 mol), the buffer can neutralize the added NaOH. Therefore, the answer is No.

Part B: Similarly, for 350 mg of KOH, we calculate the moles of KOH:

[tex]\[ \text{moles of KOH} = \frac{350 \times 10^{-3} \text{g}}{56.1 \text{g/mol}} = 6.24 \times 10^{-3} \text{mol} \][/tex]

 Since the moles of KOH are approximately equal to the moles of NaOH added in Part A and are less than the moles of HNO2 in the buffer, the buffer can neutralize the added KOH. Therefore, the answer is No.

 Part C: For 1.25 g of HBr, we calculate the moles of HBr:

[tex]\[ \text{moles of HBr} = \frac{1.25 \times 10^{-3} \text{g}}{80.9 \text{g/mol}} = 1.55 \times 10^{-2} \text{mol} \][/tex]

 Since the moles of HBr added (1.55 × 10^-2 mol) are greater than the moles of HNO2 in the buffer (5.00 × 10^-2 mol), the buffer cannot neutralize the added HBr. Therefore, the answer is Yes.

 Part D: For 1.35 g of HI, we calculate the moles of HI:

[tex]\[ \text{moles of HI} = \frac{1.35 \times 10^{-3} \text{g}}{127.9 \text{g/mol}} = 1.06 \times 10^{-2} \text{mol} \][/tex]

Since the moles of HI added (1.06 × 10^-2 mol) are greater than the moles of HNO2 in the buffer (5.00 × 10^-2 mol), the buffer cannot neutralize the added HI. Therefore, the answer is Yes.

Correction: In Part B, the moles of KOH calculated are slightly less than the moles of HNO2 in the buffer, so the buffer can neutralize the added KOH. The initial answer provided was incorrect; it should be No, not Yes. The corrected answer is No for Part B."

The volume of the buffer solution is 500.0 mL, which is equivalent to 0.500 L. The moles of HNO2 in the buffer are calculated by:

[tex]\[ \text{moles of HNO2} = \text{concentration of HNO2} \times \text{volume of buffer} = 0.100 \text{M} \times 0.500 \text{L} = 5.00 \times 10^{-2} \text{mol} \][/tex]

Since the moles of NaOH added (6.25 × 10^-3 mol) are less than the moles of HNO2 in the buffer (5.00 × 10^-2 mol), the buffer can neutralize the added NaOH. Therefore, the answer is No.

 Part B: Similarly, for 350 mg of KOH, we calculate the moles of KOH:

[tex]\[ \text{moles of KOH} = \frac{350 \times 10^{-3} \text{g}}{56.1 \text{g/mol}} = 6.24 \times 10^{-3} \text{mol} \][/tex]

 Since the moles of KOH are approximately equal to the moles of NaOH added in Part A and are less than the moles of HNO2 in the buffer, the buffer can neutralize the added KOH. Therefore, the answer is No.

Part C: For 1.25 g of HBr, we calculate the moles of HBr:

[tex]\[ \text{moles of HBr} = \frac{1.25 \times 10^{-3} \text{g}}{80.9 \text{g/mol}} = 1.55 \times 10^{-2} \text{mol} \][/tex]

 Since the moles of HBr added (1.55 × 10^-2 mol) are greater than the moles of HNO2 in the buffer (5.00 × 10^-2 mol), the buffer cannot neutralize the added HBr. Therefore, the answer is Yes.

Part D: For 1.35 g of HI, we calculate the moles of HI:

[tex]\[ \text{moles of HI} = \frac{1.35 \times 10^{-3} \text{g}}{127.9 \text{g/mol}} = 1.06 \times 10^{-2} \text{mol} \][/tex]

 Since the moles of HI added (1.06 × 10^-2 mol) are greater than the moles of HNO2 in the buffer (5.00 × 10^-2 mol), the buffer cannot neutralize the added HI. Therefore, the answer is Yes.

 Correction: In Part B, the moles of KOH calculated are slightly less than the moles of HNO2 in the buffer, so the buffer can neutralize the added KOH. The initial answer provided was incorrect; it should be No, not Yes. The corrected answer is No for Part B."

Answer:

CN⁻(aq) + H⁺(aq) → HCN(l)

Explanation:

The reactants are aqueous solutions:

NaCN(aq) and HBr(aq)

When you mix these compounds you make pure HCN (l)

The molecular equation is:

NaCN(aq) + HBr(aq) → NaBr(aq) + HCN(l)

When you dissociate the reactants, you have:

Na⁺(aq) +CN⁻(aq) + H⁺(aq) + Br⁻(aq) → Na⁺(aq) + Br⁻(aq) + HCN(l)

Sodium bromide, it is a salt, that can also be dissociated in the solution

To make, the net ionic equation you remove the repeated ions

CN⁻(aq) + H⁺(aq) → HCN(l)

The net ionic equation for the reaction between sodium cyanide and hydrobromic acid, resulting in sodium bromide and hydrocyanic acid, is CN-(aq) + H+(aq) → HCN(aq). This equation only includes the reacting species.

The reaction between sodium cyanide (NaCN) and hydrobromic acid (HBr) results in the formation of sodium bromide (NaBr) and hydrocyanic acid (HCN). This can be written as a chemical equation: NaCN(aq) + HBr(aq) → NaBr(aq) + HCN(aq). The net ionic equation for the reaction is: CN-(aq) + H+(aq) → HCN(aq). This equation represents only the species that are involved in the reaction and doesn't include the spectator ions (in this case, Na+ and Br-).

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Answer:

C7H603   +    CH3OH --> C8H803  + H2O

Balanced equation with corresponding stoichiometric numbers.

Explanation:

the salicylic acid, also called aspirin, when reacting with methanol produced an irreversible reaction giving methyl salicylate and water

Answer:

Q< K hence a precipitate will not form.

Explanation:

First convert the concentration to molL-1

For number of moles of K^+ = 0.05×20/1000 = 1×10^-3 moles

If we have 1×10^-3 moles in 20cm3

Then in 1000cm^3 we have 1×10^-3 moles×1000/20= 0.05 M

For ClO4^-= 0.50×80/1000= 0.04 moles

If we have 0.04 moles in 80cm3

Then in 1000cm^3 we have 0.04 moles×1000/80= 0.5 M

Q= [K^+] [ClO4^-]

Q= [0.05] [0.5]

Q= 0.025= 2.5×10-2

Q< K hence a precipitate will not form.

Answer:

The answer is -791.5 kJ (option c)

Explanation:

You know:

SO₂ (g) → S (s) + O₂ (g) ΔH°rxn = +296.8 kJ

2 SO₂ (g) + O₂ (g) → 2 SO₃ (g) ΔH°rxn = -197.8 kJ

You must add them to obtain the desired equation:

2 S(s) + 3 O₂(g) → 2 SO₃(g) ΔH°rxn = ?

You want to calculate the ∆H (heat of reaction) of the combustion reaction, that is, the heat that accompanies the entire reaction. The calculation is made using Hess's law. This law states: when the reactants are converted to products, the enthalpy change is the same, regardless of whether the reaction is carried out in one step or in a series of steps.

In Hess's law he explains that the enthalpy changes are additive, ΔHneta = ΣΔHr and contains three rules:

The sum of the fitted equations should give the problem equation. In this case:

2*( S(s) +  O₂(g)  → SO₂ )     To obtain the desired reaction, this equation must be inverted, so the enthalpy value is also inverted.  It must also be multiplied by 2, then the whole equation is multiplied, both reactants and products and the value of the enthalpy.  So ΔH°rxn = (-296.8 kJ)*2= -593.6 kJ

2 SO₂(g) + O₂(g) → 2 SO₃ (g)               ΔH°rxn = -197.8 kJ

____________________________________________________

2 S(s) + 3 O₂(g) → 2 SO₃(g)    ΔH°rxn =  -791.4 kJ ( Enthalpies are added algebraically)

The answer is -791.5 kJ (option c)

The value of ΔH°rxn for the 2S(s) + 3O₂(g) → 2SO₃(g) is -791.4 kJ.

Enthalpy of the reaction tells about the amount of heat released or absorbed during any chemical reaction.

Given that,

2SO₂(g) + O₂(g) → 2SO₃(g)               ΔH°rxn = -197.8 kJ

SO₂(g) → S(s) + O₂(g)                         ΔH°rxn =  296.8 kJ

To obtain the required reaction first we have to invert the second equation and multiply that by 2 and then add with the left hand side as well as the right hand side of the reaction, we get:

2S(s) + 3O₂(g) → 2SO₃(g)

ΔH°rxn of the reaction will be calculated as-

ΔH°rxn = -2(296.8 kJ) + (-197.8 kJ)

ΔH°rxn = -791.4 kJ

Hence, option (C) is correct i.e. -791.4 kJ.

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Answer:

absorbed

Explanation:

Answer:2.50 gN2

Explanation:

Pair A is:

2.50 g N2

Pair B is:

21.5 g N2

Pair C is:

0.081 CO2

The [H+] in the solution is 6.94752 * 10^−7 M.

To calculate the [H+] in the given solution, we need to first calculate the concentration of HX and then use the equilibrium constant (Ka) to find the concentration of [H+]. The equation for the dissociation of HX is: HX ⇌ H+ + X-. Since the dissociated amount is small compared to 0.803 M, we can assume that the concentration of HX is approximately 0.803 M. Now, using the equation for Ka and the concentration of HX, we can find the concentration of [H+]:

Ka = [H+][X-] / [HX]

[H+] = Ka * [HX] = (8.64 * 10^−7) * 0.803 = 6.94752 * 10^−7 M

Therefore, the [H+] in the solution is 6.94752 * 10^−7 M.

Answer:

B) 655, 485, 433, 409 nm

Explanation:

655, 485, 433, 409 nm

The greater the energy change involved in a transition, the shorter the wavelength.

Transitions to n = 2 from n = 3, 4, 5 and 6 give lines of wavelength 655, 485, 433 and 409 nm. Other answer choices represent the Lyman. Brackett, and Pfund series.

Explanation:

To alive this you need the solubility product constant of NH4Cl at 45°C

The percent composition by mass of ammonium chloride in a saturated solution at 45°C is approximately 27.17%.

To find the percent composition, we use the formula:

[tex]\[ \text{Percent composition by mass} = \left( \frac{\text{mass of solute}}{\text{mass of solution}} \right) \times 100 \][/tex]

Given that the mass of ammonium chloride (the solute) is 37.2 grams and the mass of water (the solvent) is 100 grams, the total mass of the solution is the sum of the mass of the solute and the mass of the solvent:

[tex]\[ \text{Mass of solution} = \text{Mass of solute} + \text{Mass of solvent} \][/tex]

[tex]\[ \text{Mass of solution} = 37.2 \text{ g} + 100 \text{ g} \][/tex]

[tex]\[ \text{Mass of solution} = 137.2 \text{ g} \][/tex]

Now, we can calculate the percent composition:

[tex]\[ \text{Percent composition by mass} = \left( \frac{37.2 \text{ g}}{137.2 \text{ g}} \right) \times 100 \][/tex]

[tex]\[ \text{Percent composition by mass} = \left( \frac{1}{3.68} \right) \times 100 \][/tex]

[tex]\[ \text{Percent composition by mass} \approx 27.17 \% \][/tex]

Answer:

Explanation:

check the attachment for the propose neutral  structure for each compound that is  consistent with the data.

The structures are:

A: 1-phenylethyl lactate

B:lactic acid

C: 1-phenylethanol

D: 1-phenylethanol

E: Ester formed from 1-phenylethanol lactic acid chloride

To solve this problem, we will follow the information given in the question step by step to deduce the structures of compounds A, B, C, D, and E.

1. Saponification Reaction: The ester A reacts with NaOH to produce an alcohol and a carboxylate salt. The fact that 5.30 mL of 1.00 M HCl is required to titrate the unused NaOH tells us that the rest of the NaOH was used up in the saponification reaction. We can use the moles of NaOH reacted to find the moles of ester A that reacted.

First, calculate the moles of NaOH used in the saponification:

Since the reaction is 1:1, the moles of ester A are also 9.70 mmol.

2. Molecular Formula of A: Since we have 2.00 g of A a[tex]\[ \text{Moles of NaOH used} = (15.00 \text{ mL} - 5.30 \text{ mL}) \times \frac{1.00 \text{ mmol}}{\text{mL}} \] \[ \text{Moles of NaOH used} = 9.70 \text{ mmol} \][/tex]nd we know the moles of A, we can calculate the molar mass of A:

[tex]\[ \text{Molar mass of A} = \frac{\text{mass of A}}{\text{moles of A}} \] \[ \text{Molar mass of A} = \frac{2.00 \text{ g}}{9.70 \text{ mmol}} \] \[ \text{Molar mass of A} \approx 206.19 \text{ g/mol} \][/tex]

Given that A contains only C, H, and O, we can use the molar mass to propose a molecular formula. A common approach is to start with the simplest ratio and increase it until the calculated molar mass is close to the experimental value. For example, if we start with C₃H₆O₂ (molar mass 88.09 g/mol), we can see that it's not enough. We can keep increasing the number of carbons until we reach a molar mass close to 206.19 g/mol. Let's assume the formula is C₁₂H₂₄O₄ (molar mass 248.34 g/mol), which is a common ester formula that would give us a molar mass close to the experimental value.

3. Structure of A: Since A is not oxidized by K₂Cr₂O₇ and does not decolorize Br₂ in CH₂Cl₂, it suggests that A does not have any carbon-carbon double bonds or carbon-carbon triple bonds. Therefore, A is a saturated ester. Given that A is optically active, it must contain a chiral center. A simple saturated ester with a chiral center could be butanoic acid ethyl ester with a methyl group replaced by a hydroxyl group on the alpha carbon, making it chiral.

4. Structure of B and C: B is the acid product, and C is the alcohol product from the saponification of A. Since C is oxidized to acetophenone by K2Cr2O7, C must be a secondary alcohol with a benzene ring attached to the carbon adjacent to the hydroxyl group. Therefore, C is 1-phenylethanol. B, being the acid counterpart to C, must be benzoic acid.

5. Structure of D: D is formed by the reduction of acetophenone with NaBH4. This reaction would convert the ketone to a secondary alcohol. Therefore, D is 1-phenylethyl alcohol, which is the same as C.

6. Structure of E: E is formed when D reacts with the acid chloride derived from B. Since A is reformed, E must be the product of the reaction between benzoyl chloride (from B) and 1-phenylethyl alcohol (D). E is therefore a benzoate ester with a phenylethyl group.

Based on the above analysis, the proposed structures are:

A: 1-phenylethyl lactate

B:lactic acid

C: 1-phenylethanol

D: 1-phenylethanol

E: Ester formed from 1-phenylethanol lactic acid chloride

This proposal is consistent with the given data and the reactivity of the compounds involved.

Answer:

The gaps are filled using the following;

1. removes

2. from

3. less

4. Protonated

5. Ortho, para

Explanation:

Electron density is removed from nitrogen in acetyl group which is why it is less basic

The complete sentences is now written as;

The acetyl group removes some of the electron density from the nitrogen, making it much less basic; the nitrogen of this amide is protonated under the reaction conditions. The N retains enough electron density to share with the benzene ring, so the NHCOCH3 group is still an activating ortho, para director, though weaker than NH2.

Answer:

1.64g

Explanation:

The reaction scheme is given as;

2-bromocyclohexanol  --> 1,2-epoxycyclohexane + HBr

From the reaction above,

1 mol of 2-bromocyclohexanol produces 1 mol of 1,2-epoxycyclohexane

3.0 grams of trans-2-bromocyclohexanol.

Molar mass = 179.05 g/mol

Number of moles = mass / molar mass = 3 / 179.05 = 0.016755 mol

This means  0.016755 mol of 1,2-epoxycyclohexane would be produced.

Molar mass =  98.143 g/mol

Theoretical  yield = Number of moles * Molar mass

Theoretical  yield =  0.016755 * 98.143 ≈ 1.64g

Answer:

Formic acid can react to water, to give protons to medium:

  HCOOH     +     H₂O   →     H₃O⁺     +           HCOO⁻  

Weak acid         Base          Acid           Strong conjugate base

    HCOO⁻       +     H₂O  ⇄    HCOOH     +  OH⁻                 Kb

Strong base           Acid       Weak acid       Base          

So the formate can take a proton from water to become formic acid again and that's why it is a conjugate strong base.

Explanation:

HCOOH → Formic acid

To determine the conjugate pair and to know if they are weak or strong, we should know, if they can react to water. This is called hydrolisis.

For example: formic acid is a weak acid, so the formed formate will be its conjugate base and it will be strong because the formate can react to water, to make formic again.

Weak acid → Strong conjugate base

Strong acid → Weak conjugate base

Weak base → strong conjugate acid

Strong base → weak conjugate acid

For example HCl is a strong acid. When it is in aqueous solution, we have protons and chlorides.

HCl + H₂O → H₃O⁺  + Cl⁻

Chloride will be the weak conjugate base, because it can't react to water.

We can not make HCl again, according to this equation:

Cl⁻ + H₂O ← HCl + OH⁻    This is impossible.

Formic acid can react to water, to give protons to medium:

 HCOOH     +     H₂O   →     H₃O⁺     +    HCOO⁻

Weak acid         Base          Acid           Strong conjugate base

So the formate can take a proton from water to become formic acid again and that's why it is a conjugate strong base.

    HCOO⁻       +     H₂O  ⇄    HCOOH     +  OH⁻                 Kb

Strong base           Acid       Weak acid       Base          

HCHO2 can be used to defend the statement 'A weak acid has a stronger conjugate base' as its conjugate base CHO2- readily accepts a proton thus demonstrating its strength.

I'm using HCHO2 to defend the statement 'A weak acid has a stronger conjugate base'. The weak acid formula for HCHO2 is HCHO2 → H+ + CHO2-.

The conjugate base here is CHO2-, which gains a proton (H+) to become HCHO2, demonstrating it's stronger since it readily accepts a proton.

For more such questions on conjugate base, click on:

https://brainly.com/question/35084628

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Answer:

okay so to tell the story short:

Explanation:

over the years farmers in agriculture businesses have decide to use safer chemicals. because since people have been getting food poisoning and been getting sick. but now farmer businesses now use some chemicals that have very low toxicity. When pesticides were first introduced, farmers were using chemicals that were very toxic. but then that's when they realised that the they had to be removed from the application and today they have been replaced with better and healthier ones just like (glyphosate.)

Answer:

Correct option: C

Explanation:

As given in the question that distance between two ions are same in all cases hence r is same for all.

potential energy:

[tex]P.E =\frac{k\times q_{1} \times q_{2}}{r}[/tex]

therefore potential energy depend on the two charge muliplication

so higher the charge multiplication higer will be the potential energy.

magnitude of charge multiplication follow as:

a. 1

b. 2

c. 6

d. 4

e. 2

in option C it is higher

so correct option is C

Final answer:

The ion pair with the greatest electrostatic potential energy among the given pairs is Al+3 - O-2, as it has the highest product of charges according to Coulomb's Law. Option C is correct.

Explanation:

The electrostatic potential energy between two ions is determined by Coulomb's Law, which states that the energy is proportional to the product of the charges of the ions divided by the distance between them. With all distances being equal, the pair with the greatest product of charges would have the highest electrostatic potential energy. Thus, we can compare the products of charges for each pair:

Therefore, the ion pair Al+3 - O-2 has the greatest electrostatic potential energy because the product of their charges (6) is the largest.