Calcium carbide can be made by heating calcium oxide with carbon. How many kj of heat are absorbed in the reaction?

The rate constants for the forward and reverse steps given that the forward step is first-order in A, and the reverse step is first-order in both B and C is 6.67 x 10⁻⁹ sec⁻¹.

Rate constant is defined as the proportionality constant in the equation expressing the association between a chemical reaction's pace and its constituents' concentrations. The dependence of the molar concentration of the reactants on the rate of reaction can be determined by knowing the rate constant.

Given rt = 3μs = 3 x 10⁻⁶ s

K eq = 2 x 10⁻¹⁶

B = 2 x 10⁻⁴

C = 2 x 10⁻⁴

rt = 1 / Kf + Kr

3 x 10⁻⁶ = 1 / Kf + Kr ------- ( 1 )

K eq = Kf / Kr

2 x 10⁻¹⁶ =  Kf / Kr ----------- ( 2 )

From equation 1 and 2

3 x 10⁻⁶ =  1 / Kf + Kf / 2 x 10⁻¹⁶

3 x 10⁻⁶ =  1 / 2 x 10⁻¹⁶ x Kf + Kf  / 2 x 10⁻¹⁶

Kf =  2 x 10⁻¹⁶ / 3 x 10⁻⁶ ( 2 x 10⁻¹⁶ + 1)

Kf = 6.67 x 10⁻⁹ sec⁻¹

Thus, the rate constants for the forward and reverse steps given that the forward step is first-order in A, and the reverse step is first-order in both B and C is 6.67 x 10⁻⁹ sec⁻¹.  

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Answer:

0.026%

Explanation:

The Helium-4 is the isotope of the helium that has a mass equal to 4. The element has 2 electrons, so, the total radius of the electrons is 2*2.8 = 5.6 fm = 0.0056 pm.

So, the total radius of the particles is 0.0056 + 0.0026 = 0.0082 pm.

The percentage of the space that the particles occupy is the radius of them divided by the radius of the atom:

% = 0.0082/31 *100%

% = 0.026%

* 1 fentometer (fm) = 0.001 picometer (pm)

Answer: From the attached document

1. Complete structure

2. Skeletal structure

The complete structural formula for isooctane (2,2,4-trimethylpentane) is (CH3)3CCH2CH(CH3)2, while the skeletal formula is CH3-C-(CH3)2-CH2-CH(CH3)2. These represent its molecular structure in detail and a simplified version, respectively.

The complete structural formula and skeletal formula for 2,2,4-trimethylpentane, commonly known as isooctane, are as follows:

Complete Structural Formula:

In the complete structural formula, we represent each atom in the molecule explicitly. Isooctane has the following structure:

```

     H

      |

H - C - (CH3)2

|     |

H - C - CH3

     |

     CH3

```

In this representation, each line represents a chemical bond, and we've labeled carbon (C) and hydrogen (H) atoms to show their positions in the molecule. Isooctane is highly branched, containing multiple methyl (CH3) groups attached to a central carbon atom.

Skeletal Formula:

The skeletal formula is a simplified way of representing the molecular structure. It focuses on the carbon framework, and hydrogen atoms bonded to carbon are usually omitted. Isooctane's skeletal formula is as follows:

```

  CH3

  |

CH3-C-(CH3)2

  |

  CH3

```

In this skeletal formula, each vertex represents a carbon atom, and the lines between them represent carbon-carbon bonds. The methyl (CH3) groups are indicated as branches off the carbon atoms.

Isooctane is an important component in the determination of gasoline's octane rating because it has a high resistance to engine knocking, making it a reference standard with an octane rating of 100. Gasoline blends with a higher percentage of isooctane are less prone to premature ignition and have higher octane ratings, indicating their suitability for high-performance engines.

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Complete Question:

A chemist prepares a solution of iron chloride by measuring out 0.10 g of FeCl2 into a 50. mL volumetric flask and filling to the mark with distilled water. Calculate the molarity of anions in the chemist's solution.

Answer:

[Fe+] = 0.0156 M

[Cl-] = 0.0316 M

Explanation:

The molar mass of iron chloride is 126.75 g/mol, thus, the number of moles presented in 0.10 g of it is:

n = mass/molar mass

n = 0.10/126.75

n = 7.89x10⁻⁴ mol

In a solution, it will dissociate to form:

FeCl2 -> Fe+  + 2Cl-

So, the stoichiometry is 1:1:2, and the number of moles of the ions formed are:

nFe+ = 7.89x10⁻⁴ mol

nCl- = 2*7.89x10⁻⁴  = 1.58x10⁻³ mol

The molarity is the number of moles divided by the solution volume, in L (50.0 mL = 0.05 L):

[Fe+] = 7.89x10⁻⁴/0.05 = 0.0156 M

[Cl-] = 1.58x10⁻³/0.05 = 0.0316 M

Answer:

Moles of Br₂ = 0.236 (First option)

Explanation:

Bromine gas is a diatomic molecule. Its formula is Br₂.

Moles = Mass / Molar mass

Moles = 37.7 g / 159.8 g/mol

Moles of Br₂ = 0.236

Answer:

Speed, [tex]v=\sqrt{\dfrac{2qV}{m}}[/tex]

Explanation:

The device which is used to accelerate charged particles to higher energies is called a cyclotron. It is based on the principle that the particle when placed in a magnetic field will possess a magnetic force. Just because of this Lorentz force it moves in a circular path.  

Let m, q and V are the mass, charge and potential difference at which the particle is accelerated.

The work done by the particles is equal to the kinetic energy stored in it such that,

[tex]qV=\dfrac{1}{2}mv^2[/tex]

v is the speed with which the particles enter the cyclotron

So,

[tex]v=\sqrt{\dfrac{2qV}{m}}[/tex]

So, the speed with which the particles enter the cyclotron is [tex]v=\sqrt{\dfrac{2qV}{m}}[/tex]. Hence, this is the required solution.

The speed of particles entering a cyclotron, given a potential difference V, particle mass m, and particle charge q, can be calculated using the formula v = sqrt((2qV) / m). This is based on the conversion of electrical potential energy to kinetic energy in the system.

In a cyclotron, the electrical potential energy of the particles is converted into kinetic energy. This follows the conservation of energy principle, and this transformation is described by the equation for kinetic energy, K.E. = 1/2 mv². In this case, the kinetic energy is equivalent to the energy gained from the electrical potential difference, qV (where q is the charge of the particle and V is the potential difference).

So, the equation becomes qV = 1/2 mv². Solving for the final speed v, we find that v = sqrt((2qV) / m). This equation allows us to calculate the speed at which particles enter the cyclotron, directly determined by the potential difference, particle charge (q), and particle mass (m).

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The interaction energy required to separate the chloride ion and sodium ion would be smaller if the medium between them is water, as water has a higher dielectric constant as compared to n-pentane.

The interaction energy between ions, in this case a chloride ion and a sodium ion, is dependent on the medium between them. This is described by Coulomb's law which considers the permittivity of the medium through which the force is acting. In this scenario, water has a larger dielectric constant compared to n-pentane. A higher dielectric constant significantly reduces the interaction energy because the medium is better at 'insulating' the charge of the ions from each other. Therefore, the interaction energy required to separate the ions would be smaller if they are in water as compared to n-pentane.

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Answer:

a. Dipole-dipole bonding

Explanation:

SO2 has dipole-dipole bonding. This is because of the difference in the electronegativities  of Sulphur and oxygen. Moreover, the lone pair of electrons on S gives it bent shape with a net dipole  unlike CO2 which has a linear shape.( This why CO2 does not have any dipole moment).

So, the correct answer is a.

The substance is a metal, mainly iron or copper.

Metals are classified as those elements which have a strong structure, hard, malleable, ductile, sonorous and have high heat and electricity conductivity.

Metals are not soluble in water in atomic state because they are in crystal forms which are very hard to be broken by water.

They are conductor for both heat and electricity. Metals have free electrons in their outermost shell which can be free in the lattice which helps to conduct electricity even in molten state.

And metals do usually have very high melting points. So they aren't easy to melt at all. Main conductors that are used are iron and copper.

Answer:

a) K = 5.3175

b) ΔG = 3.2694

Explanation:

a) ΔG° = - RT Ln K

∴ T = 25°C ≅ 298 K

∴ R = 8.314 E-3 KJ/K.mol

∴ ΔG° = - 4.140 KJ/mol

⇒ Ln K = - ( ΔG° ) / RT

⇒ Ln K = - ( -4.140 KJ/mol ) / (( 8.314 E-3 KJ/K.mol )( 298 K ))

⇒ Ln K = 1.671

⇒ K = 5.3175

b) A → B

∴ T = 37°C = 310 K

∴ [A] = 1.6 M

∴ [B] = 0.45 M

∴ K = [B] / [A]

⇒ K = (0.45 M)/(1.6 M)

⇒ K = 0.28125

⇒ Ln K = - 1.2685

∴ ΔG = - RT Ln K

⇒ ΔG = - ( 8.314 E-3 KJ/K.mol )( 310 K )( - 1.2685 )

⇒ ΔG = 3.2694

Answer:Iodine:

Electron configuration:

[Kr]4d10 5s2 5p5

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p5

Explanation:

Iodine is an element in group 17. It has only on umpired electron in the 5p orbital it combines with fluorine which also has one unpaired electron in its outermost orbital to form different complex interhalogen compounds by covalent bonding. These interhalogen compounds exhibit various shapes and properties.

The correct electron configuration for the element with one unpaired 5p electron that forms a covalent compound with fluorine is [Kr] 5s^2 4d^10 5p^3.

To determine the electron configuration of the element in question, we need to consider the following points:

1. The element forms a covalent compound with fluorine, which means it is likely to be a non-metal or metalloid, as these elements commonly form covalent bonds.

2. The element has one unpaired electron in the 5p subshell. This indicates that the 5p subshell is not completely filled, but it has at least one electron in it.

3. The noble gas before this element in the periodic table is krypton (Kr), which has a stable electron configuration ending in [Kr] 4s^2 4p^6.

4. The next electron added after krypton would go into the 5s subshell, followed by the 4d and then the 5p subshells, according to the Aufbau principle.

5. Since we are looking for an element with one unpaired 5p electron, we need to fill the 5s and 4d subshells completely and then partially fill the 5p subshell.

6. The 5s subshell can hold 2 electrons, and the 4d subshell can hold 10 electrons. The 5p subshell can hold 6 electrons, but we only need to add 3 electrons to it to have one unpaired electron (5p^3).

7. Therefore, the electron configuration would be [Kr] 5s^2 4d^10 5p^3, which shows a complete filling of the 5s and 4d subshells and three electrons in the 5p subshell, leaving one unpaired electron in the 5p orbital.

8. This configuration corresponds to the element iodine (I), which is known to form covalent compounds with fluorine, such as IF, IF_3, IF_5, and IF_7.

In summary, the element with one unpaired 5p electron that forms a covalent compound with fluorine is iodine, and its expected ground-state electron configuration is [Kr] 5s^2 4d^10 5p^3.

Answer: check explanation

Explanation:

Buffer solutions are solutions that have resistance towards the change in pH when H3O^+ or OH^- is added or removed. From the question, NaH2PO4 is the conjugate acid and H3Po4 is the conjugate base. Buffer solution is used for the prevention of changes due to the addition of small amounts of either strong base or strong acid.

The net ionic equations that show how NaH2PO4/H3PO4 acid/base conjugate buffer neutralizes added acid HCl and added base NaOH are written below;

H3PO4 -------------> H^+ + H2PO4^2-.

Addition of HCl;

===> H2PO4^2- + H3O^+ --------> H3PO4 + H2O.

Addition of NaOH;

====> H3PO4 + OH^- ------> H2O + H2PO4^-.

A buffer is made by dissolving H₃PO₄ and NaH2PO4 in water. The net ionic equation for the reaction with HCl shows H3PO4 converting to H2PO4-, while with NaOH, H2PO4- reacts with OH- to form H2O and HPO42-.

A buffer solution is made by dissolving H3PO4 and NaH₂PO₄ in water.

The net ionic equation for the reaction between the buffer and added HCl can be written as:

H₃PO₄ + H+ → H₂PO⁻⁴
The reaction between the buffer and added NaOH can be represented as:

H₃PO₄ + OH- → H₂O + HPO4⁻₂

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Answer:

See explanation below for answer

Explanation:

We'll do this question in two parts:

a) Weight percent of the alloy:

This is pretty easy, all we have to do is to sum the mass of each element in the alloy and then, divide each mass between the total to get the percentage in weight. In other words:

%W = m/mtotal * 100

The total mass:

mtotal = 98 + 65 = 163 g

%Sn = 98/163 * 100 = 60.12%

%Pb = 65/163 * 100 = 39.88%

b) atom percent of the alloy:

In this case, we do something similar that in part a) with the difference that instead of using mass, we will use moles of each element. The molar mass of Tin and Lead reported are 118.71 g/mol and 207.2 g/mol. The expression to use will be:

C = n/ntotal * 100

so for each element, the moles are:

moles Sn = 98/118.71 = 0.8255 moles

moles Pb = 65/207.2 = 0.3137 moles

the total moles:

ntotal = 0.8255 + 0.3137 = 1.1392 moles

So the composition in atoms for each element is:

C Sn = 0.8255/1.1392 * 100 = 72.46%

C Pb = 0.3137/1.1392 * 100 = 27.54%

The weight percent of tin in an alloy of 98 g tin and 65 g lead is 60.12%, and the weight percent of lead is 39.88%. The atom percent of tin is 71.26% and the atom percent of lead is 28.74%.

The question is asking for the composition in weight percent of an alloy that contains 98 g tin and 65 g lead, and also its composition in atom percent.

To find the weight percent of a component in an alloy, the formula is: (mass of component/total mass) x 100%. Therefore, the weight percent of tin in this alloy is: (98/(98+65)) x 100% = 60.12% and the weight percent of lead is 100% - 60.12% = 39.88%.

The composition in atom percent refers to the number of atoms of a component over the total number of atoms. Lead and tin both have different atomic masses, so we can't use the same weights. The atomic mass of tin is 118.71 g/mol and lead is 207.2 g/mol. Therefore, the atom percent of tin is: (98/118.71)/(98/118.71 + 65/207.2) x 100% = 71.26%. The atom percent of lead is 100% - 71.26% = 28.74%.

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Answer:

a. 406.3mL

b. 5519.6g

Explanation:Please see attachment for explanation

Explanation:

According to Lewis, acids are the species which readily accept electrons. Whereas bases are the species which donate electrons to electron deficient or electropositive ions.

Out of the given options, boron of [tex]BBr_{3}[/tex] and carbon of [tex](CH_{3})_{3}C^{+}[/tex] contain sextet of electrons. This means that they have accepted electrons from the combining atoms.

Thus, we can conclude that out of the given options [tex]BBr_{3}[/tex] and [tex](CH_{3})_{3}C^{+}[/tex] compounds can be labeled as Lewis acids.

BBr3 and (CH3)3C+ are the compounds that can be labeled as Lewis acids because they can accept a pair of electrons due to having an incomplete octet and a positively charged center respectively.

In the context of Lewis acid-base theory, a Lewis acid is a compound that can accept a pair of electrons, while a Lewis base is one that can donate a pair of electrons. Considering the options given:

Thus, BBr3 and (CH3)3C+ can be labeled as Lewis acids.

Answer: unit conversions can be done either simultaneously or separately

Explanation:

Dimensional analysis involves converting units within a singular calculation. It is a technique used frequently in fields like physics and engineering. Conversion factors in terms of desired and given units are used in the process.

When computing using dimensional analysis, all unit conversions must be done in a singular calculation. Dimensional analysis is a mathematical method often used in physics and engineering, and it provides a means of converting from one unit to another.

In the process of dimensional analysis, we use conversion factors that are expressed in terms of the desired unit and the given unit.

It is specifically helpful when you want to convert from one system of measurement to another, or when you need to solve a complex problem involving several different units.

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Answer: The molar mass of the unknown solute is 35.8 g/mol

Explanation:

Depression in freezing point is given by:

[tex]\Delta T_f=i\times K_f\times m[/tex]

[tex]\Delta T_f=T_f^0-T_f=(0-(-2.60))^0C=2.60^0C[/tex] = Depression in freezing point

i= vant hoff factor = 1 (for non electrolyte)

[tex]K_f[/tex] = freezing point constant = [tex]1.86^0C/m[/tex]

m= molality

[tex]\Delta T_f=i\times K_f\times \frac{\text{mass of solute}}{\text{molar mass of solute}\times \text{weight of solvent in kg}}[/tex]

Weight of solvent (water)=[tex]density\times volume =1.00g/ml\times 100ml=100g=0.1kg[/tex]      (1kg=1000g)

Molar mass of unknown non electrolyte = M g/mol

Mass of unknown non electrolyte added = 5.00 g

[tex]2.60=1\times 1.86\times \frac{5.00g}{M g/mol\times 0.100kg}[/tex]

[tex]M=35.8g/mol[/tex]

The molar mass of the unknown solute is 35.8 g/mol

The molar mass of the unknown nonelectrolytic solute is found through computing freezing point depression and molality, resulting in a molar mass of approximately 35.71 g/mol.

To solve this problem, we need to first determine the freezing point depression. Normal freezing point of water is 0°C but in this case, it is -2.60°C, hence the depression is 2.60°C. We also use the known value of the molal freezing point depression constant for water (1.86°C/m).

The formula for freezing point depression is ΔTF = KF * m, where m is the molality of the solution. By re-arranging this equation to solve for molality (m), we get m = ΔTF / KF.

Substituting the known values: m = 2.60°C / 1.86°C/m = 1.40 m. Molality means moles of solute per kilogram of solvent. In this case, we have 100 mL of water, or 0.1 kg. Therefore, the number of moles = 1.40 mol/kg * 0.1 kg = 0.14 mol.

To find the molar mass, we know that mass = number of moles * molar mass. Again, rearranging to solve for molar mass, we find that molar mass = mass / number of moles. So, substituting the known values, molar mass = 5.00g / 0.14 mol = approximately 35.71 g/mol.

Therefore, the molar mass of the unknown nonelectrolytic solute is approximately 35.71 g/mol.

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Answer:

the pressure P= 40.03 bar

Explanation:

The Van der Waals equation states that

P= R*T/(V-b) - a/V²

where

T= absolute temperature = 295 K

V= molar volume = 0.590 L/mol

R= ideal gas constant = 0.082 atm*L/mol*K

a= van der Waals parameter = 1.355 bar⋅dm⁶/mol² * (0.987 atm/bar) * (1 L²/dm⁶) = 1.337 atm ⋅L²/mol²

b= van der Waals parameter = 0.032 dm³/mol *(1 L/dm³) = 0.032 L/mol

then replacing values

P= R*T/(V-b) - a/V² = 0.082 atm*L/mol*K*295 K/( 0.590 L/mol-0.032 L/mol) -  1.337 atm ⋅L²/mol²/(0.590 L/mol)² = 39.51 atm

P= 39.51 atm / (0.987 atm/bar) = 40.03 bar

Final answer:

To calculate the pressure exerted by Ar using the van der Waals equation of state, substitute the given values for Ar, and solve for the pressure. The equation is P = [RT/(V-b)] - (a/V^2).

Explanation:

To calculate the pressure exerted by Ar using the van der Waals equation of state, we can use the equation:

P = [RT/(V-b)] - (a/V^2)

Where P is the pressure, R is the gas constant, T is the temperature, V is the molar volume, a is the van der Waals constant for the gas, and b is another van der Waals constant for the gas.

Substituting the given values for Ar, we have:

a = 1.355 bar.dm^6.mol^(-2)

b = 0.0320 dm^3.mol^(-1)

V = 0.590 L.mol^(-1)

T = 295 K

Next, we can substitute these values into the equation to calculate the pressure exerted by Ar.

Answer: The density of the given sample of hydrogen gas is 0.061 g/L

Explanation:

Assuming ideal gas behavior, the equation follows:

PV = nRT

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

Rearranging the above equation:

[tex]P=\frac{m}{M}\frac{RT}{V}[/tex]

We know that:

[tex]\text{Density}=\frac{\text{Mass}}{\text{Volume}}[/tex]

Rearranging the above equation:

[tex]P=\frac{dRT}{M}[/tex]     ......(1)

We are given:

P = pressure of the gas = 0.799 atm

d = density of hydrogen gas = ?

R = Gas constant = [tex]0.0821\text{ L . atm }mol^{-1}K^{-1}[/tex]

T = temperature of the gas = [tex]47^oC=[47+273]K=320K[/tex]

M = molar mass of hydrogen gas = 2 g/mol

Putting values in equation 1, we get:

[tex]0.799atm=\frac{d\times 0.0821\text{ L.atm }mol^{-1}K^{-1}\times 320K}{2g/mol}\\\\d=\frac{0.799\times 2}{0.0821\times 320}=0.061g/L[/tex]

Hence, the density of the given sample of hydrogen gas is 0.061 g/L

Answer:

NH3 is the limiting reactant. O2 is in excess and there will remain 0.224 grams O2

Explanation:

Step 1: Data given

Mass of NH3 = 2.25 grams

Mass of O2 = 3.38 grams

Volume of N2 = 0.450 L

Temperature = 295 K

Pressure = 1.00 atm

Molar mass NH3 = 17.03 g/mol

Molar mass O2 = 32 g/mol

Molar mass of N2 = 28 g/mol

Molar mass of H2O = 18.02 g/mol

Step 2: The balanced equation

4NH3 + 3O2 → 2N2 + 6H2O

Step 3: Calculate moles NH3

Moles NH3 = mass NH3 / molar mass NH3

Moles NH3 = 2.25 grams / 17.03 g/mol

Moles NH3 = 0.132 moles

Step 4: Calculate moles O2

Moles O2 = mass O2  / molar mass O2

Moles O2 = 3.38 grams / 32 g/mol

Moles O2 = 0.106 moles

Step 5: Calculate limiting reactant

For 4 moles NH3 we need 3 moles O2 to produce 2 moles N2 and 6 moles H2O

NH3 is the limiting reactant. It will completely be consumed (0.132 moles)

O2 is in excess. There will react 3/4 * 0.132 = 0.099 moles O2

There will remain 0.106 -0.099 = 0.007 moles O2

This is 0.007 moles * 32 g/mol = 0.224 grams

NH3 is the limiting reactant. O2 is in excess and there will remain 0.224 grams O2

Answer:

0.189

Explanation:

Aqueous solution only has ammonia and water in it. Assume total mass of 100 g

Meaning mass of ammonia is 18% of 100 g = 18 g

Mass of water is 82% of 100 g = 82g

Number of moles of ammonia  = mass / molar mass ammonia =18/17 = 1.059

Number of moles of water = mass / molar mass water = 82/18 =4.556

Mole fraction ammonia = 1.059 / (1.059+4.556) = 0.189

Final answer:

The mole fraction of ammonia in an 18.0% by mass aqueous solution of ammonia is calculated based on the ratio of moles of ammonia to total moles in the solution, resulting in a mole fraction of 0.188.

Explanation:

Mole fraction is the ratio of the moles of solute to the total moles in the solution. Given the percentage by mass, we can calculate the mole fraction of ammonia, assuming the mass of the solution is 100 grams for simplicity.

An 18.0% by mass solution means there are 18.0 grams of NH₃ and 82.0 grams of water (H₂O). To find the moles of each component, we divide their mass by their respective molar masses: NH₃ (17.031 g/mol) and H₂O (18.015 g/mol).

Moles of NH₃ = 18.0 g / 17.031 g/mol = 1.057 moles
Moles of H₂O = 82.0 g / 18.015 g/mol = 4.551 moles
The total moles in solution = 1.057 moles (NH₃) + 4.551 moles (H₂O) = 5.608 moles

The mole fraction of NH₃ = Moles of NH₃ / Total moles in solution = 1.057 / 5.608 = 0.188

Therefore, the mole fraction of ammonia in the solution is 0.188.

Answer:

a. 5.0 x 10⁷ brown grains = 50 million

b. 5.0 x 10³ brown grains = 5000

Explanation:

The concentration of 2 % brown sand means we have for every 100 grains of sand 2 are brown.

We need to calculate the number of brown sand in the bucket as follows:

= 2.5 x 10⁹  billion grains of sand x  (2 brown grains/ 100 grains of sand)

= 5.0 x 10⁷ brown grains

Likewise if the concentration of brown sand is 2.0 ppm, it mean that we have 2 brown grain per every million grains of sand.

= 2.5 x 10⁹ billion grains of sand x ( 2.0 brown grains/10⁶ grains of sand )

= 5.0 x 10³ brown grains

The answers make sense since a concentration of 1 part per million is ten thousandths of  a 1 percent

If the concentration of brown sand is 2.0%, there are 5 x 10^7 brown sand grains in the bucket.

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The question is incomplete, here is the complete question:

At 20°C the vapor pressure of benzene [tex](C_6H_6)[/tex] is 75 torr, and that of toluene [tex](C_7H_8)[/tex] is 22 torr. Assume that benzene and toluene form an ideal solution.

What is the mole fraction of benzene in the solution that has a vapor pressure of 38 torr at 20°C? Express your answer using two significant figures.

Answer: The mole fraction of benzene is 0.302

Explanation:

Let the mole fraction of benzene be 'x' and that of toluene is '1-x'

To calculate the total pressure of the mixture of the gases, we use the equation given by Raoult's law, which is:

[tex]p_T=\sum_{i=1}^n(\chi_{i}\times p_i)[/tex]

We are given:

Vapor pressure of benzene = 75 torr

Vapor pressure of toluene = 22 torr

Vapor pressure of solution = 38 torr

Putting values in above equation, we get:

[tex]38=[(75\times x)+(22\times (1-x))]\\\\x=0.30[/tex]

Hence, the mole fraction of benzene is 0.30

Final answer:

The mole fraction of benzene in a solution with a vapor pressure of 38 torr at 20 C is calculated using Raoult's law with the vapor pressure of pure benzene. The calculation yields a value of approximately 0.5086, which is rounded to 0.51 when expressed in two significant figures.

Explanation:

Calculation of Mole Fraction of Benzene in a Solution

To calculate the mole fraction of benzene in a solution based on vapor pressure data, we use Raoult's law. According to Raoult's law, the vapor pressure of a solution component is equal to the product of the mole fraction of that component in the solution and the vapor pressure of the pure component. Since the question does not specify the total vapor pressure or the vapor pressure of pure benzene at 20°C, we will refer to the additional information provided that indicates at 20°C, the vapor pressures of pure benzene and toluene are 74.7 mmHg and 22.3 mmHg, respectively, to guide the calculation. Thus, the mole fraction (X) of benzene can be found by rearranging the Raoult's law equation: P = XP0, where P is the vapor pressure of the solution, and P0 is the vapor pressure of pure benzene. This rearrangement gives us X = P / P0.

Given that the solution has a vapor pressure of 38 torr (mmHg), and using the provided vapor pressure of pure benzene ( 74.7 mmHg), the calculation for the mole fraction of benzene (XC6H6) is: XC6H6 = 38 mmHg / 74.7 mmHg

From this calculation, the mole fraction of benzene is approximately 0.5086, which can be rounded to two significant figures to give a final answer of 0.51.

Answer:

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Explanation:

During the Electron Transport System occur in the mitochondrial membrane, oxygen in this reaction is been reduced to water and ATPs are being produced.

The quinone form or the oxidized form of Flavin Adenine Dinucleotide(FAD) is the FADH2. While Nicotinamide adenine dinucleotide is the acronym for NADH. NADH is a good donating substance/agent.

It has been observed that FADH2 produce two(2) ATP while NADH produces three(3) ATP. The reason for this observation is that the production of electron in the FADH2 is at the lower enegy level. Because of this it can not transfer its electron to the first complex .

While;

NADH is at the higher energy level and it can directly transfer its electron to the first complex.

FADH2 oxidation yields one less ATP than NADH oxidation in the ETC because it enters at a lower energy Complex II, bypassing Complex I, and thus pumps fewer protons across the mitochondrial membrane, leading to the generation of fewer ATPs.

The observation that FADH2 oxidation yields one less ATP than NADH oxidation by the Electron Transport System (ETC) is explained by their respective entry points and roles in the ETC. Electrons from NADH enter at Complex I, pumping protons through complexes I, III, and IV, thus contributing to a higher proton gradient than electrons from FADH2, which enter at Complex II. Since FADH2 bypasses Complex I, it results in the pumping of fewer protons across the mitochondrial membrane, which subsequently leads to the generation of fewer ATPs during oxidative phosphorylation. Complex II directly receives electrons from the oxidation of FADH2, bypassing the first proton pump of the ETC, and as a result, less ATP is produced.

During the catabolism of glucose, a net total of 36 ATP are produced from glycolysis, the citric acid cycle, and the ETC. This includes the production of three ATPs for every NADH oxidized and two ATPs for every FADH2. The difference in ATP yield is due to the point at which each carrier donates its electrons to the ETC.

Answer:

51.2g of CO2

Explanation:

The first step is to balance the reaction equation as shown in the solution attached. Without balancing the reaction equation, one can never obtain the correct answer! Then obtain the masses of octane reacted and carbon dioxide produced from the stoichiometric equation. After that, we now compare it with what is given as shown in the image attached.

To calculate the mass of carbon dioxide produced from the complete combustion of octane, you can use the balanced chemical equation and the molar masses of octane and CO2. First, calculate the number of moles of octane, then use the ratio of CO2 to octane to find the moles of CO2. Finally, multiply the moles of CO2 by the molar mass of CO2 to find the mass of CO2 produced.

To calculate the mass of carbon dioxide produced from the complete combustion of octane (C8H18), you need to use the balanced chemical equation: 2 C8H18 + 25 O2 → 16 CO2 + 18 H2O. From this equation, you can see that for every 2 molecules of octane burned, 16 molecules of CO2 are generated. To find the mass of CO2 produced, you can use the molar mass of CO2 (44.01 g/mol) and the molar mass of octane (114.22 g/mol).

First, calculate the number of moles of octane: moles of octane = mass of octane / molar mass of octane = 16.6 g / 114.22 g/mol = 0.145 mol

Since 2 molecules of octane produce 16 molecules of CO2, you can multiply the number of moles of octane by the ratio of CO2 to octane: moles of CO2 = moles of octane x (16 mol CO2 / 2 mol octane) = 0.145 mol x (16 mol CO2 / 2 mol octane) = 1.16 mol CO2

Finally, calculate the mass of CO2 produced: mass of CO2 = moles of CO2 x molar mass of CO2 = 1.16 mol x 44.01 g/mol = 51.08 g

Therefore, the mass of carbon dioxide produced from the complete combustion of 16.6 g of octane is approximately 51.08 g.

Answer: Option (2) is the correct answer.

Explanation:

Atomic number of oxygen atom is 8 and its electronic distribution is 2, 6. So, it contains only 2 orbitals which are closer to the nucleus of the atom.

As a result, the valence electrons are pulled closer by the nucleus of oxygen atom due to which there occurs a decrease in atomic size of the atom.

Whereas atomic number of sulfur is 16 and its electronic distribution is 2, 8, 6. As there are more number of orbitals present in a sulfur atom so, the valence electrons are away from the nucleus of the atom.

Hence, there is less force of attraction between nucleus of sulfur atom and its valence electrons due to which size of sulfur atom is larger than the size of oxygen atom.

Thus, we can conclude that the oxygen atom is smaller than the sulfur atom because the outer orbitals of oxygen are located closer to the nucleus than those of sulfur.

The oxygen atom is smaller than the sulfur atom because the outer orbitals of oxygen are located closer to the nucleus than those of sulfur.

The correct option is (2) the outer orbitals of oxygen are located closer to the nucleus than those of sulfur.

To understand why the oxygen atom is smaller than the sulfur atom, we need to consider their electron configurations. Oxygen has 8 electrons and sulfur has 16 electrons. Oxygen's electron configuration is 1s²2s²2p⁴, while sulfur's electron configuration is 1s²2s²2p⁶3s²3p⁴.

The outer orbitals of an atom, which are the valence orbitals, are the ones involved in bonding. The electrons in these orbitals determine the size of the atom. In the case of oxygen and sulfur, the outer orbitals of oxygen (2p orbitals) are closer to the nucleus compared to sulfur's outer orbitals (3p orbitals). As a result, the oxygen atom is smaller than the sulfur atom.

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Final answer:

The factors to consider when choosing the ideal solvent for crystallization include solubility properties, intermolecular forces, polarity, and solvent properties such as reactivity, cost, toxicity, and boiling point.

Explanation:

When choosing the ideal solvent for the crystallization of a particular compound, several factors should be taken into consideration:

Answer: The final pressure of carbon dioxide is 15.4 atm

Explanation:

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

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

Given mass of carbonic acid = 78.2 g

Molar mass of carbonic acid = 62 g/mol

Putting values in above equation, we get:

[tex]\text{Moles of carbonic acid}=\frac{78.2g}{62g/mol}=1.26mol[/tex]

For the given chemical reaction:

[tex]H_2CO_3(aq.)\rightarrow H_2O(l)+CO_2(g)[/tex]

By Stoichiometry of the reaction:

1 mole of carbonic acid produces 1 mole of carbon dioxide

So, 1.26 moles of carbonic acid will produce = [tex]\frac{1}{1}\times 1.26=1.26mol[/tex] of carbon dioxide

To calculate the pressure, we use the equation given by ideal gas, which follows:

[tex]PV=nRT[/tex]

where,

P = pressure of the carbon dioxide = ?

V = Volume of the container = 2.00 L

T = Temperature of the container = 298 K

R = Gas constant = [tex]0.0821\text{ L. atm }mol^{-1}K^{-1}[/tex]

n = number of moles of carbon dioxide = 1.26 moles

Putting values in above equation, we get:

[tex]P\times 2.00L=1.26mol\times 0.0821\text{ L atm }mol^{-1}K^{-1}\times 298K\\\\P=\frac{1.26\times 0.0821\times 298}{2.00}=15.4atm[/tex]

Hence, the final pressure of carbon dioxide is 15.4 atm

Answer: The mass in grams for a 9.50 carat diamond is 1.9.

Explanation:

Given :

The mass of gemstones and pearls is usually expressed in units called carats.

we have to find mass in grams for 9.50 carat diamond.

1 carat = 200 mg

Thus 9.50 carat=[tex]\frac{200}{1}\times 9.50=1900mg[/tex]

Also [tex]1 mg =10^{-3}g[/tex]

Thus  [tex]1900mg =\frac{10^{-3}}{1}\times 1900=1.9g[/tex]

Thus the mass in grams for a 9.50 carat diamond is 1.9

Answer:

A and D are true , while B and F statements are false.

Explanation:

A) True.  Since the standard gibbs free energy is

ΔG = ΔG⁰ + RT*ln Q

where Q= [P1]ᵃ.../([R1]ᵇ...) , representing the ratio of the product of concentration of chemical reaction products P and the product of concentration of chemical reaction reactants R

when the system reaches equilibrium ΔG=0 and Q=Keq

0 = ΔG⁰ + RT*ln Q → ΔG⁰ = (-RT*ln Keq)

therefore the first equation also can be expressed as

ΔG = RT*ln (Q/Keq)

thus the standard gibbs free energy can be determined using Keq

B) False. ΔG⁰ represents the change of free energy under standard conditions . Nevertheless , it will give us a clue about the ΔG around the standard conditions .For example if ΔG⁰>>0 then is likely that ΔG>0 ( from the first equation) if the temperature or concentration changes are not very distant from the standard conditions

C) False. From the equation presented

ΔG⁰ = (-RT*ln Keq)

ΔG⁰>0 if Keq<1 and ΔG⁰<0 if Keq>1

for example, for a reversible reaction  ΔG⁰ will be <0 for forward or reverse reaction and the ΔG⁰ will be >0 for the other one ( reverse or forward reaction)

D) True. Standard conditions refer to

T= 298 K

pH= 7

P= 1 atm

C= 1 M for all reactants

Water = 55.6 M