1 C8H10(l) +21/2O2(g) → 8CO2(g) + 5H2O(g), Hcomb= ? Hf for C8H10(l) = +49.0kJ/mol C8H10(l) Use the balanced combustion reaction above to calculate the enthalpy of combustion (Hcomb) for C8H10

Answers

Answer 1

Answer:

[tex]H_{comb}=-4406kJ/mol[/tex]

Explanation:

Hello,

In this case, the enthalpy of combustion is understood as the energy released when one mole of fuel, in this case octene, is burned in the presence of oxygen and is computed with the enthalpies of formation of the fuel, carbon dioxide and water as shown below (oxygen is circumvented as it is a pure element):

[tex]H_{comb}=8*\Delta _fH_{CO_2}+5\Delta _fH_{H_2O}-\Delta _fH_{C_8H_{10}}[/tex]

Thus, since we already know the enthalpy of combustion of the fuel, for carbon and water we have -393.5 and -241.8 kJ/mol respectively, thereby, the enthalpy of combustion turns out:

[tex]H_{comb}=8*(-393.5kJ/mol)+5(-241.8kJ/mol)-49.0kJ/mol\\\\H_{comb}=-4406kJ/mol[/tex]

Best regards.


Related Questions

Use standard reduction potentials to calculate the equilibrium constant for the reaction: 2Cr3+(aq) + Pb(s)2Cr2+(aq) + Pb2+(aq) Hint: Carry at least 5 significant figures during intermediate calculations to avoid round off error when taking the antilogarithm. Equilibrium constant: G° for this reaction would be _________ than zero. Submit AnswerRetry Entire Group

Answers

Answer:

3.47 ×10^-10

Explanation:

The equation of the reaction is 2Cr3+(aq) + Pb(s)------->2Cr2+(aq) + Pb2+(aq)

A total of two moles of electrons were transferred in the process. The chromium was reduced while the lead was oxidized. Hence the lead species will constitute the oxidation half equation and the chromium will constitute the reduction half equation.

E°cell = E°cathode - E°anode

E°cathode = -0.41 V

E°anode = -0.13 V

E°cell = -0.41 -(-0.13) = -0.28 V

From

E°cell = 0.0592/n log K

n= 2, K= the unknown

-0.28 = 0.0592/2 log K

log K = -0.28/0.0296

log K = -9.4595

K = Antilog ( -9.4595)

K= 3.47 ×10^-10

8. A 25.0 mL sample of an H2SO4 solution is titrated with a 0.186 M NaOH solution. The equivalence point is reached with 12.9 mL of base. The concentration of H2SO4 is ________ M. (Hint: write a balanced chemical equation first!)

Answers

Answer:

  0.0480 M

Explanation:

The reaction is ...

  H₂SO₄ + 2NaOH ⇒ Na₂SO₄ +2H₂O

That is, 2 moles of NaOH react with each mole of H₂SO₄. Then the molarity of the H₂SO₄ is ...

  moles/liter = (0.186 M/2)(12.9 mL)/(25.0 mL) ≈ 0.0480 M

Write a net ionic equation to show that benzoic acid, C6H5COOH, behaves as a Brønsted-Lowry acid in water.

Answers

Answer:

H⁺(aq) + H₂O(l) ⇄ H₃O⁺(aq)

Explanation:

According to Brönsted-Lowry acid-base theory, an acid is a substance that donates H⁺. Let's consider the molecular equation showing that benzoic acid is a Brönsted-Lowry acid.

C₆H₅COOH(aq) + H₂O(l) ⇄ C₆H₅COO⁻(aq) + H₃O⁺(aq)

The complete ionic equation includes all the ions and molecular species.

C₆H₅COO⁻(aq) + H⁺(aq) + H₂O(l) ⇄ C₆H₅COO⁻(aq) + H₃O⁺(aq)

The net ionic equation includes only the ions that participate in the reaction and the molecular species.

H⁺(aq) + H₂O(l) ⇄ H₃O⁺(aq)

Elvira Walks 4 miles to the west from school and stops at the store. She then walks 3 miles south.


What is the Distance and the displacement?

Answers

Answer:

distance = 7 miles

displacement = 5 miles

Explanation:

Distance is a scalar quantity as it takes account of magnitude traveled but not the direction traveled from starting point.

The distance traveled is the sum total of distances moved

distance = 4 + 3 = 7 miles

Displacement however, is a vector and measure the shortest possible distance traveled in a given direction from the starting point.

The path of Elvis' walking forms a right-angle triangle with the hypotenuse being the displacement and the other two sides being the distance traveled west and south.

Using Pythagoras' theorem; c² = a² + b²

where c = hypotenuse and a and b are the other two sides

c² = 4² + 3²

c² = 16 + 9 = 25

√c² = √25

c = 5

Therefore, displacement = 5 miles

For the reaction of nitrogen gas and hydrogen gas to make methane, describe FOUR stresses that would shift the equilibrium to the left toward the reactants? N2(g) + 3 H2(g) ⇌ 2 NH3(g) + Energy

Answers

Answer:

- Addition of NH₃(g)

- Removal of N₂(g)

- Increase of temperature

- Pressure decrease

Explanation:

According to Le Chatelier's principle, if we apply an stress to a reaction at equilibrium, the system will try to shift the equilibrium in order to decrease the stress. If we add reactants, the equilibrium will shift toward the formation of more products (to the consumption of reactants) and vice versa.

The stresses we can apply to this equilibrium are the following:

- Addition of NH₃(g) : it is a product, thus its addition will result in a shift toward reactants.

- Removal of N₂(g): it is a reactant, thus its removal from the reaction mixture will result in a shift toward reactants.

- Increase of temperature: the reaction is exothermic, so it releases energy. Energy is a product. If we add energy (increase the temperature), we are adding a product, so the equilibrium will shift toward the reactants.

- Pressure decrease: because both reactants and products are in the gas phase. A decrease in pressure shifts an equilibrium to the side of the reaction with greater number of moles of gas. In this case, the reactants side has greater number of moles of gas (1 mol + 3 moles= 4 moles) than the products side (2 moles). Thus, the equilibrum will shift toward reactants.

For the reaction, 2SO2(g) + O2(g) <--> 2SO3(g), at 450.0 K the equilibrium con­stant, Kc, has a value of 4.62. A system was charged to give these initial concentrations, [SO3] = 0.254 M, [O2] = 0.00855 M, [SO2] = 0.500 M. In which direction will it go?

Answers

Answer:

To the left.

Explanation:

Step 1: Write the balanced reaction at equilibrium

2 SO₂(g) + O₂(g) ⇄ 2 SO₃(g)

Step 2: Calculate the reaction quotient (Qc)

Qc = [SO₃]² / [SO₂]² × [O₂]

Qc = 0.254² / 0.500² × 0.00855

Qc = 30.2

Step 3: Determine in which direction will proceed the system

Since Qc > Kc, the system will shift to the left to attain the equilibrium.

structure and correct name for 5-octyne​

Answers

Answer:

Explanation:

(R)-5-octyne-4-ol

C8H140

Correct name for 5-octyne is 3-octane.

Structure is attached below.

3-Octane:

Octane is a hydrocarbon and an alkane with the chemical formula C₈H₁₈, and the condensed structural formula CH₃(CH₂)₆CH₃. Octane has many structural isomers that differ by the amount and location of branching in the carbon chain. One of these isomers, 2,2,4-trimethylpentane (commonly called iso-octane) is used as one of the standard values in the octane rating scale.

The structure for 5-octyne is given below.

Correct name for it is 3-octane.

Find more information about Octane here:

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What happened to the limewater in
the experiment? What does this
prove?

Answers

Explanation:

In the reaction above, we clearly see that a chemical reaction took place but what kind of reaction you might ask?

Looks like it is Thermal decomposition of copper carbonate because decomposition reaction takes place due to the added heat. Decomposition in simple terms in chemical breakdown and here this result is obtained by adding heat.

1) What happened to the lime water?

Although not pictured above, but my assumption is that lime water turned milky or turbid because when CO2 comes in presence of limewater they react to form a percipitate of Calcium carbonate which is the milky color that you get.

2) What does this prove?

- My understanding would be that it proves that CO2 was formed, and that most metal carbonates undergo thermal decomposition into metal oxide and carbon dioxide, and also that a reaction took place since new products were made.

Which land feature supports the theory of continental drift?

A.canyons B.volcanoes C.coal fields D.oceans

Answers

Answer:

Coals

Explanation:

The land feature that supports the theory of continental drift is ; ( C ) coal fields

Continental drift is the gradual shift in position of the earth tectonic plates ( i.e. gradual shift in the continents in relation to ocean basins) and this due to the heat from the earths' mantle.

Coal fields supports this theory because the it is an area where coal is found in large quantities and mined for commercial purposes. coal fields areas are found as a result of continental drift.

Hence we can conclude that the land feature that supports the theory of continental drift is coal fields

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A chemistry student weighs out of ascorbic acid , a diprotic acid, into a volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with solution. Calculate the volume of solution the student will need to add to reach the final equivalence point. Round your answer to significant digits.

Answers

Answer:

14.3 mL  

Explanation:

Assume the student used 0.113 g ascorbic acid  and 0.0900 mol·L⁻¹ NaOH.

1. Balanced chemical equation.

The formula of ascorbic acid is H₂C₆H₆O₆ (MM = 176.12 g/mol).

However, for the balanced equation, let's write it as H₂A.

[tex]\rm H_{2}A + 2NaOH \longrightarrow Na_{2}A + 2H_{2}O[/tex]

2. Moles of ascorbic acid

[tex]\text{Moles of H$_{2}$A} =\text{0.113 g H$_{2}$A} \times \dfrac{\text{1 mmol H$_{2}$A}}{\text{0.176 12 mg H$_{2}$}A} = \text{0.6416 mmol H$_{2}$A}[/tex]

3. Moles of NaOH

The molar ratio is 2 mmol NaOH:1 mmol H₂A.

[tex]\text{Moles of NaOH}= \text{0.6416 mmol H$_{2}$A} \times \dfrac{\text{2 mmol NaOH}}{\text{1 mmol H$_{2}$A}} =\text{1.283 mmol NaOH}[/tex]

4. Volume of NaOH

[tex]V = \text{1.283 mmol NaOH}\times \dfrac{\text{1 mL NaOH}}{\text{0.0900 mmol NaOH}} = \textbf{14.3 mL NaOH}\\\\\text{The student will need $\large \boxed{\textbf{14.3 mL NaOH}}$}[/tex]

What is the name of CaCl2 7H2o

Answers

Answer:

calcium chloride dihydrate

Use the following reactions and given Δh values to find standard enthalpies of reactions (in kilojoules) given below.C(s)+O2(g)→CO2(g) ΔH= -393.5 kJ 2CO(g)+O2(g)→2CO2(g) ΔH= -566.0 kJ2H2(g)+O2(g)→2H2O(g) ΔH= -483.6 kJ

Answers

Answer:

The heat of the reaction or standard enthalpy of the reaction CO(g) + H₂O(g) → CO₂(g) + H₂(g) is ΔH(rxn) = -41.2 kJ

Explanation:

The reaction whose standard enthalpy is required, as obtained from the internet is

CO(g) + H₂O(g) → CO₂(g) + H₂(g)

The formation reaction for some of the reactants and products are given as

C(s) + O₂(g) → CO₂(g) ΔH = -393.5 kJ

2CO(g) + O₂(g) → 2CO₂(g) ΔH = -566.0 kJ

2H₂(g) + O₂(g) → 2H₂O(g) ΔH = -483.6 kJ

To find the standard enthalpies of the given reaction, we need the heat of formation of each of the species involved in the reaction

ΔH (CO₂(g)) = -393.5 kJ

ΔH (H₂O(g)) = -483.6 kJ ÷ 2 = -241.8 kJ (Because 2 moles of H₂O(g) are formed in the given formation reaction)

ΔH (O₂(g)) = ΔH (H₂(g)) = 0 kJ (No heat of formation for elements)

ΔH (CO(g)) = ? (This isn't given)

But it can be calculated from the second given reaction

2CO(g) + O₂(g) → 2CO₂(g) ΔH = -566.0 kJ

Heat of reaction = ΔH(products) - ΔH(reactants)

Heat of reaction = -566.0 kJ

ΔH (products) = 2 × ΔH (CO₂(g)) = 2 × -393.5 = -787 kJ

ΔH (reactants) = [2 × ΔH (CO(g))] + [1 × ΔH (O₂(g))] = 2 × ΔH (CO₂(g))

Hence, we have

-566 = -787 - [2 × ΔH (CO₂(g))]

2 × ΔH (CO₂(g)) = -787 + 566 = -221 kJ

ΔH (CO₂(g)) = -221 ÷ 2 = -110.5 kJ

CO(g) + H₂O(g) → CO₂(g) + H₂(g)

Heat of reaction = ΔH(products) - ΔH(reactants)

ΔH (products) = [ΔH (CO₂(g))] + [ΔH (H₂(g))]

= -393.5 + 0 = -393.5 kJ

ΔH (reactants) = [1 × ΔH (CO(g))] + [1 × ΔH (H₂O(g))] = -110.5 - 241.8 = -352.3 kJ

Heat of reaction = -393.5 - (-352.3) = -41.2 kJ

Hope this Helps!!!

Why at night, under the mercury or sodium vapor lights in a mall parking lot, do cars seem to be peculiar colors?

Answers

Answer:

Here's what I find  

Explanation:

Sodium vapour produces mostly yellow light.

Mercury vapour produces mostly blue light.

A white car reflects all colours back to our eyes.

A coloured car, say green, absorbs all the other colours and reflects the green.

Under a sodium light, a white or a yellow car will appear yellow. A red car will be nearly black because there is no red light to reflect.

Under a mercury light, a white or a blue car will appear blue. A yellow car will be quite dark, but there will be a yellowish tinge because there is some yellow in the Hg spectrum for it to reflect.  

The picture below shows a red car and a black car under sodium light. Can you tell which is which?

What is the pH of a solution prepared by dissolving 0.140 g of potassium hydroxide in sufficient pure water to prepare 250.0 ml of solution

Answers

Answer:

pH= 12

Explanation:

Potassium hydroxide (KOH) is a strong base, so it dissociates completely in water by giving OH⁻ anions as follows:

KOH⇒ K⁺ + OH⁻

Since dissociation is complete, it is assumed that the concentration of OH⁻ is equal to the initial concentration of KOH:

[OH⁻]= [KOH]

In order to find the initial concentration of KOH, we have to divide the mass (0.140 g) into the molecular weight of KOH (Mw):

Mw (KOH)= K + O + H = 39 g/mol + 16 g/mol + 1 g/mol = 56 g/mol

moles KOH: mass/Mw= 0.140 g/(56 g/mol) = 2.5 x 10⁻³ moles

The molality of the solution is the number of moles of KOH per liter of solution:

V= 250.0 ml x 1 L/1000 ml= 0.250 L

M = (2.5 x 10⁻³moles)/(0.250 L)= 0.01 M

Now, we calculate pOH:

pOH = -log [OH⁻]= - log [KOH]= -log (0.01) = 2

Finally, we calculate pH from pOH:

pH + pOH = 14

⇒pH = 14 - pOH= 14 -2 = 12

Think about what you know about science today. How do you think scientific knowledge will be different in 100 years?

Answers

Answer:

I think we will know a lot more about the universe and the things around us. We may also know a lot more about other planets, such as Mars and Saturn, and we might also know a lot more about other stars in the universe.

Explanation:

Balance the chemical equation
Fe2O3 (s) + CO (g) 2 Fe(s) + CO2 (g)
Express your answer as a chemical equation. Identify all of the phases in your answer.

Answers

Answer:

[tex]Fe_2O_3+3CO\Rightarrow \:2Fe+3CO_2[/tex]

Explanation:

[tex]Fe_2O_3+CO\Rightarrow \:2Fe+CO_2\\\\Fe_2O_3+3CO\Rightarrow \:2Fe+3CO_2[/tex]

Best Regards!

4. The pH of an aqueous solution is determined to be 1.50.
Calculate the hydronium ion concentration.
b. Calculate the hydroxide ion concentration.​

Answers

-lg[H+]=1.5

which means that [H+]=0.03M

pOH=14-pH=14-1.5=12.5

-lg[H+]=1.5

which means that [H+]=0.03M

pOH=14-pH=14-1.5=12.5

the hydroxide ion concentration. is 12.5.

How do you find hydronium ion concentration when given pH?

The hydronium ion concentration can be found from the pH by the reverse of the mathematical operation employed to find the pH. [H3O+] = 10-pH or [H3O+] = antilog (- pH) Example: What is the hydronium ion concentration in a solution that has a pH of 8.34? On a calculator, calculate 10-8.34, or "inverse" log ( - 8.34).

What is the pH of a solution that has a hydronium ion concentration of 0.025 M?

For a 0.025 M HCl solution the concentration of the hydrogen ions, [H+] , is 0.025 moles/liter (i.e. 0.025 M). pH is defined as −log[H+] . Substituting 0.025 into the equation for pH we find that the 0.025 M HCl solution has a pH of -log(0.025) = 1.60.

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Which best describes the relationship between heat internal energy, and thermal energy?
O Internal energy is heat that flows, and heat is the part of thermal energy that can be transferred.
O Internal energy is thermal energy that flows, and thermal energy is the part of heat that can be transferred.
O Thermal energy is heat that flows, and heat is the part of internal energy that can be transferred.
O Heat is thermal energy that flows, and thermal energy is the part of internal energy that can be transferred.

Answers

Answer:

Heat is thermal energy that flows, and thermal energy is the part of internal energy that can be transferred

Explanation:

Based on the properties of the compounds in the interactive, predict whether the given compounds behave as electrolytes or as nonelectrolytes.
1. LioH
2. C4H2O4
3. LiBr
4. HNo3

Answers

Explanation:

Before proceeding we have to understand what electrolytes and non electrolytes are;

An electrolyte is a substance that produces an electrically conducting solution when dissolved. An electrolyte is a compound that can dissociate into ions.

Non electrolytes: A substance whose molecules in solution do not dissociate to ions and thus do not conduct an electric current

Going through the options;

1. LiOH

This is a compound of hat would dissociate into Li+ and OH-.  This is an electrolyte.

2. C4H2O4

This is an organic compound. Gnerally organic acids are non electrolytes, with the exception og the acids. This is a nonelectrolyte.

3. LiBr

This is an electrolyte because it would dissociate into Li+ and Br-  ions.

4. HNO3

HNO3 is a strong acid. Because it is a strong acid it will dissociate completely into its ions (H+ and NO3-). Therefore we consider HNO3 to be a strong electrolyte.

differentiate between satured and unsatured fats

Answers

Answer:

...

Explanation:

in saturated fats there is no double bond between the acids and are tightly packed and unsaturated fats arent tight and loosely packed/put together

saturated- solid at room temperature

unsaturated= liquid at room temperature

two types of unsaturated fats, Polyunsaturated fats and Monounsaturated fats

The electron in a hydrogen atom, originally in level n = 8, undergoes a transition to a lower level by emitting a photon of wavelength 3745 nm. What is the final level of the electron?(c=3.00×10^8m/s, h=6.63×10^-34 J·s, RH=2.179×106-18J)a. 5



b. 6



c. 8



d. 9



e. 1

Answers

Explanation:

It is given that,

The electron in a hydrogen atom, originally in level n = 8, undergoes a transition to a lower level by emitting a photon of wavelength 3745 nm. It means that,

[tex]n_i=8[/tex]

[tex]\lambda=3745\ nm[/tex]

The amount of energy change during the transition is given by :

[tex]\Delta E=R_H[\dfrac{1}{n_f^2}-\dfrac{1}{n_i^2}][/tex]

And

[tex]\dfrac{hc}{\lambda}=R_H[\dfrac{1}{n_f^2}-\dfrac{1}{n_i^2}][/tex]

Plugging all the values we get :

[tex]\dfrac{6.63\times 10^{-34}\times 3\times 10^8}{3745\times 10^{-9}}=2.179\times 10^{-18}[\dfrac{1}{n_f^2}-\dfrac{1}{8^2}]\\\\\dfrac{5.31\times 10^{-20}}{2.179\times 10^{-18}}=[\dfrac{1}{n_f^2}-\dfrac{1}{8^2}]\\\\0.0243=[\dfrac{1}{n_f^2}-\dfrac{1}{64}]\\\\0.0243+\dfrac{1}{64}=\dfrac{1}{n_f^2}\\\\0.039925=\dfrac{1}{n_f^2}\\\\n_f^2=25\\\\n_f=5[/tex]

So, the final level of the electron is 5.

An atom of element number 33 (As) is in its ground electronic state. Which one of the following sets quantum numbers could not apply to any of its electrons?
A) n=2 l=1 ml= -1 ms= 1/2
B) n=3 l=0 ml=0 ms= -1/2
C) n=3 l=2 ml=-2 ms= -1/2
D) n=4 l=0 ml=0 ms= -1/2
E) n=4 l=2 ml=1 ms= 1/2

Answers

Answer:

E) n=4 l=2 ml=1 ms= 1/2

Explanation:

Arsenic is a member of group 15 in the periodic table. Its electronic configuration is;

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p3. Its condensed electronic configuration can be written as [Ar]4s2 3d10 4p3. This electronic configuration shown here can now enable us to consider each option given in the question in order to meaningfully arrive at a logical answer.

If we look at option E, the data given for that electron is; n=4 l=2 ml=1 ms= 1/2. This refers to an electron in a 4d orbital. In the ground state configuration of arsenic shown above, there is no 4d orbital, hence option E must be the correct answer.

A 5.00g of X, the product of organic synthesis is obtained in a 1.0 dm3 aqueous solution. Calculate the mass of X that can be extracted from the aqueous solution by a 50cm3 of ethoxy ethane. (KD (X) =40.​

Answers

Answer:

mass of X extracted from the aqueous solution by 50 cm³ of ethoxy ethane = 3.33 g

Explanation:

The partition coefficient of X between ethoxy ethane (ether) and water, K is given by the formula

K = concentration of X in ether/concentration of X in water

Partition coefficient, K(X) between ethoxy ethane and water = 40

Concentration of X in ether = mass(g)/volume(dm³)

Mass of X in ether = m g

Volume of ether = 50/1000 dm³ = 0.05 dm³

Concentration of X in ether = (m/0.05) g/dm³

Concentration of X in water = mass(g)/volume(dm³)

Mass of X in water left after extraction with ether = (5 - m) g

Volume of water = 1 dm³

Concentration of X in water = (5 - m/1) g/dm³

Using K = concentration of X in ether/concentration of X in water;

40 = (m/0.05)/(5 - m)

(m/0.05) = 40 × (5 - m)

(m/0.05) = 200 - 40m

m = 0.05 × (200 - 40m)

m = 10 - 2m

3m = 10

m = 10/3

m = 3.33 g of X

Therefore, mass of X extracted from the aqueous solution by 50 cm³ of ethoxy ethane = 3.33 g

A 25.0-mL sample of 0.150 M hydrazoic acid, HN3, is titrated with a 0.150 M NaOH solution. What is the pH after 13.3 mL of base is added? The Ka of hydrazoic acid = 1.9 x 10-5.

Answers

Answer:

pH ≅ 4.80

Explanation:

Given that:

the volume of HN₃ = 25 mL = 0.025 L

Molarity of HN₃ = 0.150 M

number of moles of HN₃ = 0.025 × 0.150

number of moles of HN₃ =  0.00375  mol

Molarity of NaOH = 0.150 M

the volume of NaOH = 13.3 mL = 0.0133

number of moles of NaOH = 0.0133× 0.150

number of moles of NaOH = 0.001995 mol

The chemical equation for the reaction of this process can be written as:

[tex]HN_3 + OH- ---> N^-_{3} + H_2O[/tex]

1 mole of hydrazoic acid react with 1 mole of hydroxide to give nitride ion and water

thus the new number of moles of HN₃ = 0.00375 - 0.001995 = 0.001755 mol

Total volume used in the reaction =  0.025 +  0.0133 = 0.0383  L

Concentration of [tex]HN_3[/tex] = [tex]\dfrac{0.001755}{0.0383}[/tex] = 0.0458 M

Concentration of [tex]N^{-}_3[/tex] = [tex]\dfrac{ 0.001995 }{0.0383}[/tex] = 0.0521 M

GIven that :

Ka = [tex]1.9 x 10^{-5}[/tex]

Thus; it's pKa = 4.72

[tex]pH =4.72 + log(\dfrac{ \ 0.0521}{0.0458})[/tex]

[tex]pH =4.72 + log(1.1376)[/tex]

[tex]pH =4.72 + 0.05598[/tex]

[tex]pH =4.77598[/tex]

pH ≅ 4.80

The pH of the solution 0.150 M hydrazoic acid after 13.3 mL of NaOH base is added is 4.80.

How we calculate the pH?

pH of the given solution will be used by using the following equation:

pH = pKa + log[conjugate base] / [weak acid]

Given chemical reaction will be represented as:

HN₃ + OH⁻ → N₃⁻ + H₂O

Moles will be calculated as:

n = M×V, where

M = molarity

V = volume

Moles of 0.150 M hydrazoic acid = (0.150M)(0.025L) = 0.00375  mol

Moles of 0.150 M NaOH = (0.0133)(0.150) = 0.001995 mol

From the above calculation it is clear that moles of hydrazoic acid is present in excess and it will be:

0.00375 - 0.001995 = 0.001755 mol

And 0.001995 mol of N₃⁻ is preduced by the reaction.

Total volume of the solution = 0.025 +  0.0133 = 0.0383  L

To calculate the pH after titration, first we have to calculate the concentration in terms of molarity of N₃⁻ and HN₃ as:

[N₃⁻] = 0.001995 mol / 0.0383  L = 0.0521 M

[HN₃] = 0.001755 mol / 0.0383  L = 0.0458 M

Ka for HN₃ = 1.9 × 10⁻⁵

pKa = -log( 1.9 × 10⁻⁵ ) = 4.72

On putting all these values on the above equation, we get

pH = 4.72 + log (0.0521) / (0.0458)

pH = 4.80

Hence, pH of the solution is 4.80.

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A beach has a supply of sand grains composed of calcite, ferromagnesian silicate minerals, and non-ferromagnesian silicate minerals. If it undergoes lots of chemical weathering, which sand grains will be quickly chemically weathered away?

a. Calcite
b. ferromagnesian silicate minerals
c. non-ferromagnesian silicate minerals

Answers

ferromagnesian silicate minerals (i looked it up)

The sand that grained will be quickly chemically weathered away should be option b. ferromagnesian silicate minerals.

What are ferromagnesian silicate minerals?

It should be considered as the Silicate minerals where cations of iron and the form of magnesium should be important for the chemical components. It is used for covering up the minerals. Also, calcite should be normal weather via the solution process so it required a lot of water that contains a high amount of carbonic acid.

Hence, the correct option is b.

Learn more about mineral here: https://brainly.com/question/20772787

c) What is the pH of the buffer system in part a when 0.030 moles of strong acid are added (without a change in volume)

Answers

Answer:

remain the same

Explanation:

The pH of the buffer system remain the same when 0.030 moles of strong acid are added because buffer system has the property to resist any change in the pH  when acid or base is added to the solution. In buffer system, one molecule is responsible for neutralizing the pH of the solution by giving H+ or OH-.This molecule is known as buffer agent. If more base is added, the molecule provide H+ and when more acid is added to the solution, then the molecule add OH- to the solution.

"The pH of a solution of household ammonia, a 0.950-M solution of NH3, is 11.612. What is Kb" for NH3

Answers

Answer:

Kb = 1.77x10⁻⁵

Explanation:

When NH₃, a weak base, is in equilibrium with waterm the reaction that occurs is:

NH₃(aq) + H₂O(l) ⇄ NH₄⁺(aq) + OH⁻(aq)

And the dissociation constant, Kb, for this equilibrium is:

Kb = [NH₄⁺] [OH⁻] / [NH₃]

To find Kb you need to find the concentration of each species. The equilibrium concentrations are:

[NH₃] = 0.950M - X

[NH₄⁺] = X

[OH⁻] = X

Where X is reaction coordinate.

You can know [OH⁻] and, therefore, X, with pH of the solution, thus:

pH = -log [H⁺] = 11.612

[H⁺] = 2.4434x10⁻¹²

As 1x10⁻¹⁴ = [H⁺] [OH⁻]

1x10⁻¹⁴ / 2.4434x10⁻¹² = [OH⁻]

4.0926x10⁻³ = [OH⁻] = X

Replacing, concentrations of the species are:

[NH₃] = 0.950M - X

[NH₄⁺] = X

[OH⁻] = X

[NH₃] = 0.9459M

[NH₄⁺] = 4.0926x10⁻³M

[OH⁻] = 4.0926x10⁻³M

Replacing in Kb expression:

Kb = [NH₄⁺] [OH⁻] / [NH₃]

Kb = [4.0926x10⁻³M] [4.0926x10⁻³M] / [0.9459M]

Kb = 1.77x10⁻⁵

The branch of science which deals with the chemical bond is called Chemistry.

The correct answer to the question is  [tex]Kb = 1.77*10^{-5[/tex]

Explanation:

When NH₃, is acts as a  weak base it forms an equilibrium with water the reaction occurs is:

[tex]NH_3(aq) + H_2O(l) ---><NH_4^+(aq) + OH^-(aq)[/tex]

The formula we gonna use is as follows:-

[tex]Kb = \frac{[NH_4^+] [OH^-]}{[NH_3]}[/tex]

The data is given in the question is as follows:-

[NH₃] = 0.950M - X [NH₄⁺] = X [OH⁻] = X

Where X stands for reaction coordinate.

After solving the ph of the compound the value is as follows:-

[NH₃] = [tex]0.9459M[/tex] [NH₄⁺] = [tex]4.0926*10^{-3}M[/tex] [OH⁻] = [tex]4.0926*10^{-3}M[/tex]

Putting the value in the formula.

[tex]Kb = \frac{[4.0926*10^{-3}M] [4.0926*10^{-3}M]}{[0.9459M]}[/tex]

After solving the equation the value of Kb is [tex]1.77*10^{-5[/tex]

Hence, the correct answer is [tex]1.77*10^{-5[/tex]

For more information, refer to the link:-

https://brainly.com/question/25026730

which process is used to produce gases from solutions of salts dissolved in water or another liquid?

A.Electrolysis
B.Metallic bonding
C.Ionic bonding
D. Polar covalent bonding

Answers

Answer:

A.Electrolysis

Explanation:

A.Electrolysis

For example,  electrolysis of solution of NaCl in water gives H2 and O2.

A correct name for the following compound is:_________.a) 4-bromo-3,8-dimethylbicyclo[5.2.2]nonane b) 3,8-dimethyl-4-bromo-bicyclo[5.2.O)nonane c) 4-bromo-3,8-dimethylbicyclo[5.2.1]decane d) 7-bromo-2,6-dimethylbicyclo[5.2.0]nonane e) 4-bromo-3,8-dimethylbicyclo[5.2.0]nonane

Answers

Answer:

e) 4-bromo-3,8-dimethylbicyclo[5.2.0]nonane

Explanation:

The missing image of the the  compound we are to name is attached below.

Before we can name an organic compound; It is crucial we know the guiding rules in naming them.

1. Select the longest continuous carbon chain as the root hydrocarbon and name according to the number of carbon atoms it contains, adding appropriate suffix to indicate the principal substituent group.

2. Number the carbon atoms in the root hydrocarbon from the end which gives the lowest number to the substituents.

3. If the same substituent is present two  or more times  in a molecule; the number of this substituent is indicated by the prefix di -(2), tri - (3) , tetra - (4) etc attached to the substituent name.

4. If there is more than one type of substituent in the molecule ; the substituents are named according to the alphabetical order but where  there are mixed substituents ; the inorganic are named first.

5. In selecting and numbering the longest continuous chain, the functional groups are given preference over substituents., i.e the functional group is given the smallest possible number.

In the light of the above guiding rules; we were able to name the given compound because the compound contains nine carbons in the ring form which result to root name nonane. The two methyl are on the third and eight carbon; bromine is on the fourth carbon ; there are two cyclic ring present in the compound where we have 5 carbons in one structure, another 2 carbons in the second structure and zero carbon in the bridge structure which eventually result to the correct  name:

4-bromo-3,8-dimethylbicyclo[5.2.0]nonane

The reduction of iron(III) oxide to iron metal is an endothermic process: Fe2O3(s) + 2 CO(g) → 2 Fe(s) + 3 CO2(g) ΔH = +26.3 kJ How many kilojoules of energy are required to produce 1.00 kilogram of iron metal?

Answers

Answer: Thus 234 kJ of energy are required to produce 1.00 kilogram of iron metal

Explanation:

To calculate the number of moles , we use the equation:

[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]  

Putting values , we get:

[tex]\text{Moles of iron}=\frac{1000g}{56g/mol}=17.8moles[/tex]    (1.00kg=1000g)

The balanced chemical reaction is:

[tex]Fe_2O_3(s)+2CO(g)\rightarrow 2Fe(s)+3CO_2(g)[/tex]   [tex]\Delta H=+26.3kJ[/tex]

Given :

Energy released when 2 moles of [tex]Fe[/tex] is produced = 26.3 kJ

Thus Energy released when 17.8 moles of [tex]Fe[/tex] is produced =

= [tex]\frac{26.3kJ}{2}\times 17.8=234kJ[/tex]

Thus 234 kJ of energy are required to produce 1.00 kilogram of iron metal

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