Fluorine-18 is a radioactive isotope that decays by positron emission to form oxygen-18 with a half-life of 109.8 min. (A positron is a particle with the mass of an electron and a single unit of positive charge.) What is the rate constant (in min−1) for the decomposition of fluorine-18?

Answer:

Molality for this solution is 0.31 m

Explanation:

Molality → Mol of solute / kg of solvent

Mass of solute = 1.85 g (CO(NH₂)₂

% by mass, means mass of solute in 100 g of solution

Mass of solution = Mass of solute + Mass of solvent

As 1.85 g is the mass of solute, the mass of solvent would be 98.15 g to complete the 100g of solution.

Let's convert the mass of solvent (g to kg)

1 g = 1×10⁻³ kg

98.2 g .  1×10⁻³ kg / 1g = 0.0982 kg

Let's convert the mass of solute to moles (mass / molar mass)

1.85 g / 60 g/mol = 0.0308 mol

Molality = 0.0308 mol / 0.0982 kg → 0.31 m

To find the molality of the solution, we calculate the number of moles of urea (0.031 mol) and the mass of water (0.10315 kg). The molality is then computed as moles of urea divided by the mass of water, which comes out to be approximately 0.30 m.

To calculate the molality of the solution, we need to first know the number of moles of the solute (urea) and the mass of the solvent (water) in kilograms.

The mass % of the solution is given as 1.85%, meaning that we have 1.85g of urea in 100g of the solution. Considering that the molar mass of urea (CO(NH2)2) is about 60.06 g/mol, the number of moles of urea can be calculated as follows: Moles of urea = mass / molar mass = 1.85g / 60.06 g/mol ≈ 0.031 mol.

Since the density of the solution is given as 1.05 g/mL, the mass of the solution for 100 mL (or 100g since density = mass/volume) would be 100 mL * 1.05 g/mL = 105g. In this 105g of the solution, 1.85g is urea, so the mass of water (solvent) would be 105g - 1.85g = 103.15g or 0.10315 kg (since 1g = 0.001 kg).

Molality is the number of solute's moles divided by the mass of solvent (in kg). Thus, the molality of the solution would be: Molality = moles of urea / mass of water in kg = 0.031 mol / 0.10315 kg ≈ 0.30 mol/kg or 0.30 m.

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To calculate the radius of an atom in a body-centered cubic (BCC) structure, we can use the formula: radius (r) = √(3/4) * a/2, where a is the lattice constant.

In a body-centered cubic (BCC) unit cell, the atoms in the corners do not touch each other but contact the atom in the center. The unit cell contains two atoms: one-eighth of an atom at each of the eight corners and one atom in the center. An atom in a BCC structure has a coordination number of eight. To calculate the radius of an atom in a BCC structure, we can use the formula:

Radius (r) = √(3/4) * a/2

where a is the lattice constant. Plugging in the given value of the lattice constant as 409, we can calculate the radius of the atom of metal M in a BCC structure using this formula.

Answer:

Solution with 35.0 g of [tex]C_3H_8O[/tex] in 250.0 g of ethanol will have lowest freezing point

Explanation:

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

where,

[tex]\Delta T_f[/tex] =depression in freezing point =  

[tex]K_f[/tex] = freezing point constant  

m = molality

As we can see that higher the molality of the solution more will depression in freezing point of the solution and hence lower will the freezing point of solution.

[tex]Molality=\frac{moles}{\text{mass of solvent in kg}}[/tex]

A. 35.0 g of [tex]C_3H_8O[/tex] in 250.0 g of ethanol.

Moles of [tex]C_3H_8O[/tex]=[tex]\frac{35.0 g}{60 g/mol}=0.5833 mol[/tex]

Mass of solvent i.e. ethanol = 250.0 g = 0.25 kg (1 g = 0.001 kg)

[tex]m=\frac{0.5833 mol}{0.25 kg}=2.33 m[/tex]

B. 35.0 g of [tex]C4H_{10}O[/tex] in 250.0 g of ethanol

Moles of [tex]C_4H_{10}O[/tex][tex]=[tex]\frac{35.0 g}{74 g/mol}=0.4730 mol[/tex]

Mass of solvent i.e. ethanol = 250.0 g = 0.25 kg (1 g = 0.001 kg)

[tex]m'=\frac{0.4730 mol}{0.25 kg}=1.89 m[/tex]

C. 35.0 g of [tex]C_2H_{6}O_2[/tex] in 250.0 g of ethanol

Moles of [tex]C_2H_{6}O_2[/tex]=[tex]\frac{35.0 g}{62g/mol}=0.5645 mol[/tex]

Mass of solvent i.e. ethanol = 250.0 g = 0.25 kg (1 g = 0.001 kg)

[tex]m''=\frac{0.5645 mol}{0.25 kg}=2.26 m[/tex]

[tex]m>m'''>m''[/tex]

Solution with 35.0 g of [tex]C_3H_8O[/tex] in 250.0 g of ethanol will have lowest freezing point

Answer: The value of [tex][OH^-][/tex] for the solution is [tex]10^{-6}M[/tex]

Explanation:

To calculate the concentration of hydroxide ion for the solution, we use the equation:

[tex][H^+]\times [OH^-]=10^{-14}[/tex]

We are given:

[tex][H^+]=100\times [OH^-][/tex]

Putting values in above equation, we get:

[tex]100\times [OH^-]\times [OH^-]=10^{-14}[/tex]

[tex][OH^-]^2=\frac{10^{-14}}{100}[/tex]

[tex][OH^-]=\sqrt{10^{-12}}[/tex]

[tex][OH^-]=10^{-6}M[/tex]

Hence, the value of [tex][OH^-][/tex] for the solution is [tex]10^{-6}M[/tex]

Answer:

Pressure and volume

Explanation:

The ideal gas equation is given below:

PV = nRT

P = nRT /V

If nRT is constant,

P will be inversely proportional to V(P & 1/V)

Therefore, pressure and volume are inversely proportional if all factors remains constant

In an ideal gas, pressure and volume are inversely proportional to each other if all other factors remain constant. This is known as Boyle's Law.

In an ideal gas, pressure and volume are inversely proportional to each other if all other factors remain constant.

This is known as Boyle's Law, which states that when the volume of a given amount of gas is decreased, the pressure increases, and vice versa.

For example, if the volume of a gas is reduced by half, the pressure will double, and if the volume is doubled, the pressure will be halved.

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The full set of quantum numbers varies depending on the electron being considered in each element or ion, with the numbers consisting of the principal quantum number (n), angular momentum quantum number (l), magnetic quantum number (m_l), and spin quantum number (m_s).

Quantum numbers describe values of conserved quantities in the dynamics of a quantum system, which in this case are the electrons in various elements or ions.

Answer:

Option b. 0.048 M

Explanation:

We have the molecular weight and the mass, from sulcralfate.

Let's convert the mass in g, to moles

1 g . 1 mol / 2087 g = 4.79×10⁻⁴ moles.

Molarity is mol /L

Let's convert the volume of solution in L

10 mL . 1L/1000 mL = 0.01 L

4.79×10⁻⁴ mol / 0.01 L = 0.048 mol/L

Answer:

a relief valve is inserted in the downstream line from the pressure regulator.

Explanation:

Whenever dry nitrogen from a portable cylinder is used in service and installation practice the item of most importance in consideration of safety is a relief valve is inserted in the downstream line from the pressure regulator.

The most important item to consider for safety when using dry nitrogen from a portable cylinder in service and installation practice is a pressure regulator, which controls the flow and release of the gas. It is also crucial to inspect the system for leaks regularly.

When using dry nitrogen from a portable cylinder in service and installation practice, the most important item to consider for safety is a pressure regulator. A pressure regulator is used to control the flow and release of nitrogen gas from the cylinder. It ensures that the pressure does not exceed safe limits and reduces the risk of an explosion or other accidents.

Additionally, it is crucial to always check for leaks in the system before using dry nitrogen. Leaks can result in the accumulation of nitrogen gas, which can displace oxygen in the air and lead to asphyxiation. Therefore, regularly inspecting the system and using appropriate leak detection methods, such as soapy water or a leak detection solution, is essential for safety.

In summary, when working with dry nitrogen from a portable cylinder, the two most important safety considerations are the use of a pressure regulator and regular inspection for leaks.

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Answer: The number of moles of hydrogen gas generated is [tex]2.33\times 10^{-3}mol[/tex]

Explanation:

To calculate the number of moles of hydrogen gas, we use the equation given by ideal gas which follows:

[tex]PV=nRT[/tex]

where,

P = pressure of the gas = 0.781 atm

V = Volume of the gas = 71.85 mL = 0.07185 L     (Conversion factor:  1 L = 1000 mL)

T = Temperature of the gas = [tex]20^oC=[20+273]K=293K[/tex]

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

n = number of moles of hydrogen gas = ?

Putting values in above equation, we get:

[tex]0.781atm\times 0.07185L=n\times 0.0821\text{ L.atm }mol^{-1}K^{-1}\times 293K\\\\n=\frac{0.781\times 0.07185}{0.0821\times 293}=2.33\times 10^{-3}mol[/tex]

Hence, the number of moles of hydrogen gas generated is [tex]2.33\times 10^{-3}mol[/tex]

To calculate the concentration of Cl2O5 in the vessel 5.70 seconds later, use the first-order rate law equation and the given rate constant and initial concentration.

To calculate the concentration of Cl2O5 in the vessel 5.70 seconds later, we can use the first-order rate law equation.

The rate law equation for a first-order reaction is: ln([A]t/[A]0) = -kt

Where [A]t is the concentration at time t, [A]0 is the initial concentration, k is the rate constant, and t is the time.

In this case, we know the rate constant (k) is 0.184 s^-1 and the initial concentration ([A]0) is 1.16 M. We need to find the concentration at 5.70 seconds ([A]t).

Plugging in the values: ln([A]t/1.16) = -0.184 * 5.70

Solving for [A]t, we find that the concentration of Cl2O5 in the vessel 5.70 seconds later is approximately 0.64 M.

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Given data: Rate constant (k) = 0.184 s⁻¹

Initial concentration (Cl₂O₅) = 1.16 M

Time (t) = 5.70 s

To find the concentration of Cl₂O₅ after 5.70 seconds  

We know that the first-order integrated rate law equation is:

ln([A]t/[A]0) = -where [A]t and [A]0 are the concentrations of reactant at time 't' and initial time '0' respectively. We can rearrange this equation to find the concentration of the reactant at any time 't':[A]t = [A]0 × e^(-kt)Putting the values in the equation, we get:

[Cl₂O₅]5.70 = 1.16 M × e^(-0.184 s⁻¹ × 5.70 s)

[Cl₂O₅]5.70 = 0.501

Therefore, the concentration of Cl₂O₅ in the vessel 5.70 seconds later is 0.501 M.

a) The molality of the 1.22 M sugar solution is approximately [tex]\(1.089 \, \text{mol/kg}\).[/tex]

b) The molality of the 0.87 M NaOH solution is approximately [tex]\(0.8365 \, \text{mol/kg}\).[/tex]

c) The molality of the 5.24 M NaHCO3 solution is approximately [tex]\(4.4034 \, \text{mol/kg}\).[/tex]

(a) 1.22 M sugar (C12H22O11) solution:

Given:

- Molarity (\(M\)) of sugar solution = 1.22 M

- Density of solution = 1.12 g/ml

We'll assume that the density given is for the solution and not just for water.

1. Calculate the mass of 1 L (1000 ml) of solution:

[tex]\[ \text{mass of solution} = \text{density} \times \text{volume} \][/tex]

[tex]\[ \text{mass of solution} = 1.12 \, \text{g/ml} \times 1000 \, \text{ml} \][/tex]

[tex]\[ \text{mass of solution} = 1120 \, \text{g} \][/tex]

2. Convert the mass of the solution to kilograms:

[tex]\[ \text{mass of solution in kg} = \frac{{1120 \, \text{g}}}{{1000}} = 1.12 \, \text{kg} \][/tex]

3. Calculate the moles of sugar (C12H22O11):

[tex]\[ \text{moles of sugar} = \text{Molarity} \times \text{volume in L} \][/tex]

[tex]\[ \text{moles of sugar} = 1.22 \, \text{mol/L} \times 1 \, \text{L} = 1.22 \, \text{mol} \][/tex]

4. Calculate the molality ([tex]\(m\)[/tex]):

[tex]\[ m = \frac{{\text{moles of sugar}}}{{\text{mass of solvent in kg}}} \][/tex]

Let's perform the calculation.

For the 1.22 M sugar solution:

1. Calculate the mass of 1 L (1000 ml) of solution:

[tex]\[ \text{mass of solution} = \text{density} \times \text{volume} \][/tex]

[tex]\[ \text{mass of solution} = 1.12 \, \text{g/ml} \times 1000 \, \text{ml} \][/tex]

[tex]\[ \text{mass of solution} = 1120 \, \text{g} \][/tex]

2. Convert the mass of the solution to kilograms:

[tex]\[ \text{mass of solution in kg} = \frac{{1120 \, \text{g}}}{{1000}} = 1.12 \, \text{kg} \][/tex]

3. Calculate the moles of sugar (C12H22O11):

[tex]\[ \text{moles of sugar} = \text{Molarity} \times \text{volume in L} \][/tex]

[tex]\[ \text{moles of sugar} = 1.22 \, \text{mol/L} \times 1 \, \text{L} = 1.22 \, \text{mol} \][/tex]

4. Calculate the molality ([tex]\(m\)[/tex]):

[tex]\[ m = \frac{{\text{moles of sugar}}}{{\text{mass of solvent in kg}}} \][/tex]

[tex]\[ m = \frac{{1.22 \, \text{mol}}}{{1.12 \, \text{kg}}} \][/tex]

[tex]\[ m \approx 1.089 \, \text{mol/kg} \][/tex]

So, the molality of the 1.22 M sugar solution is approximately [tex]\(1.089 \, \text{mol/kg}\).[/tex]

(b) 0.87 M NaOH solution:

Given:

- Molarity ([tex]\(M\)[/tex]) of NaOH solution = 0.87 M

- Density of solution = 1.04 g/ml

We'll follow the same steps as above to calculate the molality.

Let's calculate for the NaOH solution.

For the 0.87 M NaOH solution:

1. Calculate the mass of 1 L (1000 ml) of solution:

[tex]\[ \text{mass of solution} = \text{density} \times \text{volume} \][/tex]

[tex]\[ \text{mass of solution} = 1.04 \, \text{g/ml} \times 1000 \, \text{ml} \][/tex]

[tex]\[ \text{mass of solution} = 1040 \, \text{g} \][/tex]

2. Convert the mass of the solution to kilograms:

[tex]\[ \text{mass of solution in kg} = \frac{{1040 \, \text{g}}}{{1000}} = 1.04 \, \text{kg} \][/tex]

3. Calculate the moles of NaOH:

[tex]\[ \text{moles of NaOH} = \text{Molarity} \times \text{volume in L} \][/tex]

[tex]\[ \text{moles of NaOH} = 0.87 \, \text{mol/L} \times 1 \, \text{L} = 0.87 \, \text{mol} \][/tex]

4. Calculate the molality (\(m\)):

[tex]\[ m = \frac{{\text{moles of NaOH}}}{{\text{mass of solvent in kg}}} \][/tex]

[tex]\[ m = \frac{{0.87 \, \text{mol}}}{{1.04 \, \text{kg}}} \][/tex]

[tex]\[ m = \frac{{0.87 \, \text{mol}}}{{1.04 \, \text{kg}}} \][/tex]

[tex]\[ m \approx 0.8365 \, \text{mol/kg} \][/tex]

So, the molality of the 0.87 M NaOH solution is approximately [tex]\(0.8365 \, \text{mol/kg}\).[/tex]

(c) 5.24 M NaHCO3 solution:

Given:

- Molarity (\(M\)) of NaHCO3 solution = 5.24 M

- Density of solution = 1.19 g/ml

Let's follow the same steps as above to calculate the molality for the NaHCO3 solution.

For the 5.24 M NaHCO3 solution:

1. Calculate the mass of 1 L (1000 ml) of solution:

[tex]\[ \text{mass of solution} = \text{density} \times \text{volume} \][/tex]

[tex]\[ \text{mass of solution} = 1.19 \, \text{g/ml} \times 1000 \, \text{ml} \][/tex]

[tex]\[ \text{mass of solution} = 1190 \, \text{g} \][/tex]

2. Convert the mass of the solution to kilograms:

[tex]\[ \text{mass of solution in kg} = \frac{{1190 \, \text{g}}}{{1000}} = 1.19 \, \text{kg} \][/tex]

3. Calculate the moles of NaHCO3:

[tex]\[ \text{moles of NaHCO3} = \text{Molarity} \times \text{volume in L} \][/tex]

[tex]\[ \text{moles of NaHCO3} = 5.24 \, \text{mol/L} \times 1 \, \text{L} = 5.24 \, \text{mol} \][/tex]

4. Calculate the molality (\(m\)):

[tex]\[ m = \frac{{\text{moles of NaHCO3}}}{{\text{mass of solvent in kg}}} \][/tex]

[tex]\[ m = \frac{{5.24 \, \text{mol}}}{{1.19 \, \text{kg}}} \][/tex]

[tex]\[ m = \frac{{5.24 \, \text{mol}}}{{1.19 \, \text{kg}}} \][/tex]

[tex]\[ m \approx 4.4034 \, \text{mol/kg} \][/tex]

So, the molality of the 5.24 M NaHCO3 solution is approximately [tex]\(4.4034 \, \text{mol/kg}\).[/tex]

Answer:

Well in comparison of Ni (II) and Ni (IV), Ni (IV) is a stronger vation with the +4 charge so it will attract the more oxygen ions in the aqueous solution. That is why Ni (IV) will be more strongly hydrated.

Explanation:

Final answer:

In an aqueous solution, the Ni (IV) cation is more strongly hydrated than the Ni (II) cation due to its higher charge density, which attracts more water molecules into its hydration sphere.

Explanation:

In an aqueous solution containing Ni (II) and Ni (IV) salts, the Ni (IV) cation is expected to be more strongly hydrated. This outcome is attributed primarily to the charge density. The Ni (IV) has a higher charge (+4) compared to Ni (II) which has a +2 charge. In terms of hydration, water molecules, which act as dipoles, are more strongly attracted to ions with a higher charge density. This means that the Ni (IV) ion, with its higher charge, attracts and binds water molecules more strongly than the Ni (II) ion.

This strong attraction results in a greater degree of hydration for the Ni (IV) ion as it pulls more water molecules into its hydration sphere. This process is crucial in understanding the properties of solutions, especially in predicting the behavior of ions in biological and chemical systems.

Answer: a) The [tex]K_a[/tex] of acetic acid at [tex]25^0C[/tex] is [tex]1.82\times 10^{-5}[/tex]

b) The percent dissociation for the solution is [tex]4.27\times 10^{-3}[/tex]

Explanation:

[tex]CH_3COOH\rightarrow CH_3COO^-H^+[/tex]

 cM              0             0

[tex]c-c\alpha[/tex]        [tex]c\alpha[/tex]          [tex]c\alpha[/tex]

So dissociation constant will be:

[tex]K_a=\frac{(c\alpha)^{2}}{c-c\alpha}[/tex]

Give c= 0.10 M and [tex]\alpha[/tex] = ?

Also [tex]pH=-log[H^+][/tex]

[tex]2.87=-log[H^+][/tex]  

[tex][H^+]=1.35\times 10^{-3}M[/tex]

[tex][CH_3COO^-]=1.35\times 10^{-3}M[/tex]

[tex][CH_3COOH]=(0.10M-1.35\times 10^{-3}=0.09806M[/tex]

Putting in the values we get:

[tex]K_a=\frac{(1.35\times 10^{-3})^2}{(0.09806)}[/tex]

[tex]K_a=1.82\times 10^{-5}[/tex]

b)  [tex]\alpha=\sqrt\frac{K_a}{c}[/tex]

[tex]\alpha=\sqrt\frac{1.82\times 10^{-5}}{0.10}[/tex]

[tex]\alpha=4.27\times 10^{-5}[/tex]

[tex]\% \alpha=4.27\times 10^{-5}\times 100=4.27\times 10^{-3}[/tex]

The Ka of acetic acid is calculated using the pH and the definition of Ka using an ICE table, then percent dissociation is calculated using the initial concentration and the concentration of H+ found. We first calculate [H+] using the pH, then input those values into the Ka expression to find Ka, then use the formula for percent dissociation to find the percent dissociation.

To solve this problem, we will first calculate the Ka using the known pH and the equilibrium relationship between the pH, Ka and [H+] concentration. Then we will calculate the percent dissociation of the acetic acid.

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Answer:

it contains 11 electrons

Explanation:

Answer: The coefficient in front of AgCl when the equation is properly balanced is 2.

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

Decomposition is a type of chemical reaction in which one reactant gives two or more than two products.

Decomposition of silver chloride is represented as:

[tex]2AgCl(s)\rightarrow 2Ag(s)+Cl_2(g)[/tex]

Thus the coefficient in front of AgCl when the equation is properly balanced is 2.

Answer:

the coefficient in front of AgCl(s) when the equation is properly balanced is 2.

Explanation:

The decomposition of solid silver chloride (AgCl) into its elements when exposed to sunlight can be represented by the following balanced chemical equation:

2AgCl(s) → 2Ag(s) + Cl2(g)

In this balanced equation:

The coefficient in front of AgCl(s) is 2.

The coefficient in front of Ag(s) is 2.

The coefficient in front of Cl2(g) is also 2.

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Explanation:

It is known that for a body centered cubic unit cell there are 2 atoms per unit cell.

This means that volume occupied by 2 atoms is equal to volume of the unit cell.

So, according to the volume density

        [tex]5 \times 10^{26} atoms = 1 [tex]m^{3}[/tex]

        2 atoms = [tex]\frac{1 m^{3}}{5 \times 10^{26} atoms} \times 2 atoms[/tex]

                     = [tex]4 \times 10^{-27} m^{3}[/tex]

Formula for volume of a cube is [tex]a^{3}[/tex]. Therefore,

           Volume of the cube = [tex]4 \times 10^{-27} m^{3}[/tex]

As lattice constant (a) = [tex](4 \times 10^{-27} m^{3})^{\frac{1}{3}}[/tex]

                                   = [tex]1.59 \times 10^{-9} m[/tex]

Therefore, the value of lattice constant is [tex]1.59 \times 10^{-9} m[/tex].

And, for bcc unit cell the value of radius is as follows.

                 r = [tex]\frac{\sqrt{3}}{4}a[/tex]

Hence, effective radius of the atom is calculated as follows.

                 r = [tex]\frac{\sqrt{3}}{4}a[/tex]

                   = [tex]\frac{\sqrt{3}}{4} \times 1.59 \times 10^{-9} m[/tex]

                   = [tex]6.9 \times 10^{-10} m[/tex]

Hence, the value of effective radius of the atom is [tex]6.9 \times 10^{-10} m[/tex].

Answer:

b. Pepsin

Explanation:

In the stomach, when dygestion takes place,pepsinogen is secreted  in the stomach for the dygestion of proteins, which are catalyzed to aminoacids for the use of the body.

When the pepsinogen gets in contact with the HCl it converts to pepsin, which is the actived form of the pepsinogen.

Pepsinogen is converted into its active form, called Pepsin, under acidic conditions rendered by Hydrochloric acid (HCl). Pepsin, once activated, aids in protein digestion.

Pepsinogen, an inactive protease, is secreted by the chief cells located in the stomach. Under the acidic condition produced by the presence of Hydrochloric acid (HCl), pepsinogen is converted into its active form, known as Pepsin. Pepsin plays an integral role in the process of digestion, specifically assisting in the breakdown of proteins in the stomach.

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Answer:

The deprotonated organic acid (RCO2-) and protonated organic base (RNH3+) go into the aqueous layer because Organic compounds that are neither acids or bases do not react with either NaOH or HCl and, therefore remain more soluble in the organic solvent and are not extracted.

Explanation:

When 5 moles of silver sulfide react with 8 moles of aluminum metal, there is an excess of aluminum. After the reaction is complete, 3.3 moles of the excess aluminum remain unreacted.

The balanced chemical equation for the reaction between solid silver sulfide (Ag2S) and aluminum metal (Al) is:

3Ag2S + 2Al → 6Ag + Al2S3

Based on this equation, we can see that every 3 moles of Ag2S react with 2 moles of Al to produce 6 moles of Ag and 1 mole of Al2S3.

In the given question, 5 moles of Ag2S react with 8 moles of Al. Therefore, we have an excess of Al. To determine the moles of excess Al remaining unreacted, we can set up a ratio:

(8 moles Al reacted) / (2 moles Al required to react with 3 moles Ag2S) = x moles Ag2S / 5 moles Ag2S

Simplifying this ratio, we find:

x = (8 moles Al / 2) × (5 moles Ag2S / 3 moles Al)

x = 20/6 = 3.3 moles

Therefore, 3.3 moles of the excess reactant (Al) remain unreacted when the reaction is over.

Final answer:

After writing a balanced chemical equation for the reaction between silver sulfide and aluminum, we determine that 4.7 moles of aluminum remain unreacted when 5 moles of silver sulfide react with 8 moles of aluminum.

Explanation:

To determine the number of moles of the excess reactant that remain unreacted, we first need to write a balanced chemical equation for the reaction between silver sulfide and aluminum metal. Here is the balanced equation:

3 Ag₂S (s) + 2 Al (s) → 6 Ag (s) + Al₂S₃(s)

Using the balanced equation, we see that 3 moles of silver sulfide react with 2 moles of aluminum. Therefore, if we had 5 moles of silver sulfide, we would need 2/3 × 5 = 10/3 moles of aluminum to react completely with the silver sulfide.

Since 8 moles of aluminum were originally present, we subtract the amount of aluminum that reacted to find the excess:

8 moles Al - 10/3 moles Al = 14/3 moles Al

Thus, 14/3 moles or 4.7 moles of aluminum remain unreacted.

Answer: The new water level when silver metal is submerged is 18.24 mL

Explanation:

We are given:

Volume of graduated cylinder = 15.0 mL

To calculate volume of a substance, we use the equation:

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

Density of silver metal = 10.5 g/mL

Mass of silver metal = 34.0 g

Putting values in above equation, we get:

[tex]10.5g/mL=\frac{34.0g}{\text{Volume of silver metal}}\\\\\text{Volume of silver metal}=\frac{34.0g}{10.5g/mL}=3.24mL[/tex]

New water level = Volume of silver metal + Volume of graduated cylinder

New water level = (3.24 + 15.0) mL = 18.24 mL

Hence, the new water level when silver metal is submerged is 18.24 mL

Answer: a:6 electrons, b:10electrons, c: 2electrons

Explanation:

1.Principle quantum number(n)

n is the number of shell, it is a positive integer. The maximum number of electrons in a shell is 2(n2)

2.Azimuthal quantum number(l)

l is the number of subshell in the principal shell

The name of subshell are s, p, d, f

The number of nodes in each subshell is

s is l=0, p is l=1, d is l=2, f is l=3.

Each shell can have 2 x l + 1 sublevels, and each sublevel can accommodate maximum of 2 electrons and have two electrons.

A. n=2, l=1 then 2 x 1 + 1= 3 subshell, 3*2= 6 electrons in the p subshell

b. 3d, d is l = 2 then 2 x 2 + 1 = 5 sublevels, 5*2=10 electrons in the d subshell

c. 4s, s is l=0 then 2 x 0 + 1 = 1 sublevel, 1*2=2 electrons in the s subshell.

Explanation:

As per the measurements that are made by the student are as follows.

        21.6 cm is equivalent to 8.5 inch

Therefore, 1 cm for the given situation will be equivalent to inch as follows.

              1 cm = [tex]\frac{8.5}{21.6}[/tex] inch

                      = 0.393 inch

Hence, we will calculate the ratio of cm : inch as follows.

               Ratio of cm : inch = [tex]\frac{8.5}{21.6}[/tex]

                                             = 0.39

Thus, we can conclude that the ratio of cm/inch using the students data is 0.39.

Answer:

48.5 kJ

Explanation:

Let's consider the sublimation of carbon dioxide at its sublimation temperature, that is, its change from the solid to the gaseous state.

CO₂(s) → CO₂(g)

The molar mass of carbon dioxide is 44.01 g/mol. The moles corresponding to  66.0 g are:

66.0 g × (1 mol/44.01 g) = 1.50 mol

The heat of sublimation for carbon dioxide is 32.3 kJ/mol. The heat required to sublimate 1.50 moles of carbon dioxide is:

1.50 mol × (32.3 kJ/mol) = 48.5 kJ

Answer:

(a) F⁻(g) ⇒ F⁺(g)         ΔE=2009 KJ/mol

(b) Na⁺(g) ⇒ Na⁻(g)   ΔE=-548.6 KJ/mol

Explanation:

Hess's Law

"Energy changes for a reaction is independent of steps or route involved."

Now the conversion F⁻ to F⁺ is a two step reaction. In first step F⁻ loses an electron e⁻ to become neutral atom.

F⁻ ⇒ F + e⁻   ΔH=328 KJ/mol (i)

Kindly note this energy is derived from electron affinity, which is the energy changes while adding an electron to neutral atom and its same while removing an electron from ion.

In second step,

Another electron is removed from F.

F ⇒ F⁺ + e⁻    ΔH= 1681 KJ/mol (ii)

This energy is 1st ionization energy for F, which is the energy required to remove first electron from outer most shell of neutral atom.

Now the total energy change can be found by applying Hess's law and adding equations (i) and (ii);

F⁻ ⇒ F + e⁻   ΔH=328 KJ/mol

F ⇒ F⁺ + e⁻    ΔH= 1681 KJ/mol

F⁻ ⇒ F⁺ + 2e⁻  ΔH= 2009 KJ/mol

This reaction involves two steps in first Na⁺(g) gains electron and become neutral atom while in second step Na(g) accepts another electron to become Na⁻(g).

Na⁺(g) + e⁻⇒ Na(g)    ΔH=-495.8 KJ/mol   (i)

Na(g) + e⁻ ⇒ Na⁻(g)   ΔH=-52.8 KJ/mol     (ii)   (By Applying Hess's Law)

Na⁺(g) + 2e⁻ ⇒ Na⁻(g)  ΔH=-548.6 KJ/mol

Kindly note as there is no molar change in above mentioned reactions therefore enthalpy changes(ΔH) and internal energy changes(ΔE) are same.

Answer:

Room B contains the greater mass of air

Explanation:

According to the given data, the volume of both rooms is the same, so let's consider both volumes as V. An open door connects both the room, which infer that pressure for both the rooms is also the same, let it be P.

Considering the above conditions, the general gas equation for the air in both rooms can be given as:

[tex]PV=n_{A}RT_{A}\\ \\ PV=n_{B}RT_{B}[/tex]

Here, n represents the moles of air, R is the gas constant, and T is the temperature. Taking the ratio of both the above equations we get

[tex]\frac{PV}{PV}= \frac{n_{A}RT_{A}}{n_{B}RT_{B}}\\[/tex]

moles of the gas are mass per molecular mass, as the molecular mass is the same in both the cases so n can be replaced by m, as follows

[tex]\frac{PV}{PV}= \frac{m_{A}RT_{A}}{m_{B}RT_{B}}\\[/tex]

By simplifying we get,

[tex]\frac{m_{A}}{m_{B}}=\frac{T_{B}}{T_{A}}[/tex]

According to the given conditions, TA is greater than TB. So from the derived relation, it can be seen that the mass of air in room B is greater than the mass of air in room A.

Answer: The concentration of salt (sodium sulfate), sulfuric acid and NaOH in the solution is 0.0418 M, 0.0999 M and 0 M respectively.

Explanation:

To calculate the number of moles for given molarity, we use the equation:

[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}[/tex]     .....(1)

For NaOH:

Initial molarity of NaOH solution = 0.195 M

Volume of solution = 15.0 mL = 0.015 L   (Conversion factor:   1 L = 1000 mL)

Putting values in equation 1, we get:

[tex]0.195M=\frac{\text{Moles of NaOH}}{0.015L}\\\\\text{Moles of NaOH}=(0.195mol/L\times 0.015L)=2.925\times 10^{-3}mol[/tex]

For sulfuric acid:

Initial molarity of sulfuric acid solution = 0.248 M

Volume of solution = 20.0 mL = 0.020 L

Putting values in equation 1, we get:

[tex]0.248M=\frac{\text{Moles of }H_2SO_4}{0.020L}\\\\\text{Moles of }H_2SO_4=(0.248mol/L\times 0.020L)=4.96\times 10^{-3}mol[/tex]

The chemical equation for the reaction of NaOH and sulfuric acid follows:

[tex]2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O[/tex]

By Stoichiometry of the reaction:

2 moles of NaOH reacts with 1 mole of sulfuric acid

So, [tex]2.925\times 10^{-3}[/tex] moles of KOH will react with = [tex]\frac{1}{2}\times 2.925\times 10^{-3}=1.462\times 10^{-3}mol[/tex] of sulfuric acid

As, given amount of sulfuric acid is more than the required amount. So, it is considered as an excess reagent.

Thus, NaOH is considered as a limiting reagent because it limits the formation of product.

Excess moles of sulfuric acid = [tex](4.96-1.462)\times 10^{-3}=3.498\times 10^{-3}mol[/tex]

By Stoichiometry of the reaction:

2 moles of KOH produces 1 mole of sodium sulfate

So, [tex]2.925\times 10^{-3}[/tex] moles of KOH will produce = [tex]\frac{1}{2}\times 2.925\times 10^{-3}=1.462\times 10^{-3}mol[/tex] of sodium sulfate

Moles of sodium sulfate = [tex]1.462\times 10^{-3}moles[/tex]

Volume of solution = [15.0 + 20.0] = 35.0 mL = 0.035 L

Putting values in equation 1, we get:

[tex]\text{Molarity of sodium sulfate}=\frac{1.462\times 10^{-3}}{0.035}=0.0418M[/tex]

Moles of excess sulfuric acid = [tex]3.498\times 10^{-3}mol[/tex]

Volume of solution = [15.0 + 20.0] = 35.0 mL = 0.035 L

Putting values in equation 1, we get:

[tex]\text{Molarity of sulfuric acid}=\frac{3.498\times 10^{-3}}{0.035}=0.0999M[/tex]

Moles of NaOH remained = 0 moles

Volume of solution = [15.0 + 20.0] = 35.0 mL = 0.035 L

Putting values in equation 1, we get:

[tex]\text{Molarity of NaOH}=\frac{0}{0.050}=0M[/tex]

Hence, the concentration of salt (sodium sulfate), sulfuric acid and NaOH in the solution is 0.0418 M, 0.0999 M and 0 M respectively.

After the reaction between solutions of H2SO4 and NaOH is complete, the remaining concentrations are 0.0317 M H2SO4, 0 M NaOH, and 0.0836 M Na2SO4 are formed.

The balanced chemical equation for the reaction between sulfuric acid (H2SO4) and sodium hydroxide (NaOH) is: H2SO4 + 2NaOH -> Na2SO4 + 2H2O. This equation shows that one mole of sulfuric acid reacts with two moles of sodium hydroxide to produce one mole of sodium sulfate (Na2SO4) and two moles of water.

Using this stoichiometry, the moles of H2SO4 and NaOH in the solutions can be calculated with moles = concentration x volume (in L). That gives us 0.020 L * 0.248 mol/L = 0.00496 mol for H2SO4 and 0.015 L * 0.195 mol/L = 0.002925 mol for NaOH.

Since one mole of H2SO4 reacts with two moles of NaOH, all of the NaOH will react, and you will have 0.00496 mol - 2* 0.002925 mol = 0.00111 mol of H2SO4 left. The concentration of H2SO4 then is 0.00111 mol / 0.035 L (sum of volumes) = 0.0317 M.

NaOH is completely reacted, so its concentration is 0 M. From the reaction stoichiometry, 0.002925 mol of Na2SO4 is formed, so its concentration is 0.002925 mol / 0.035 L = 0.0836 M.

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Electromagnetic radiation can be arranged by wavelength, frequency, or energy. In increasing order, by wavelength, it is: X-ray, Ultraviolet, Visible, Infrared, Microwave, Radio waves. In increasing order, by frequency and energy, it is: Radio waves, Microwave, Infrared, Visible, Ultraviolet, X-ray.

The types of electromagnetic radiation listed can be arranged by wavelength, frequency, and energy. The relationship among these three properties is that as wavelength increases, frequency and energy decrease, and vice versa.

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Answer : The electron configurations consistent with this fact is, (b) [Kr] 4d¹⁰  

Explanation :

Electronic configuration : It is defined as the representation of electrons around the nucleus of an atom.

Number of electrons in an atom are determined by the electronic configuration.

Paramagnetic compounds : They have unpaired electrons.

Diamagnetic compounds : They have no unpaired electrons that means all are paired.

The given electron configurations of Palladium are:

(a) [Kr] 5s²4d⁸

In this, there are 2 electrons in 's' orbital and 8 electrons in 'd' orbital. From the partial orbital diagrams we conclude that 's' orbital are paired but 'd' orbital are not paired. So, this configuration shows paramagnetic.

(b) [Kr] 4d¹⁰

In this, there are 10 electrons in 'd' orbital. From the partial orbital diagrams we conclude that electrons in 'd' orbital are paired. So, this configuration shows diamagnetic.

(c) [Kr] 5s¹4d⁹

In this, there are 1 electron in 's' orbital and 9 electrons in 'd' orbital. From the partial orbital diagrams we conclude that 's' orbital and 'd' orbital are not paired. So, this configuration shows paramagnetic.

The correct electron configuration for a diamagnetic substance like Palladium (Pd) is [Kr] 4d¹⁰. This is because diamagnetic substances like Palladium need to have all their electron orbitals fully filled, thereby having no unpaired electrons.

The subject of this question is about the electron configuration of Palladium (Pd; Z 46), which is a diamagnetic element. Diamagnetic substances have no unpaired electrons and are not attracted to a magnetic field. Thus, to be consistent with this fact, the electron configuration of Palladium must not have any unpaired electrons.

(a) [Kr] 5s²4d⁸: This configuration would imply there are unpaired electrons in the 4d orbital, which contradicts the fact that Palladium is diamagnetic.

(b) [Kr] 4d¹⁰: This configuration correctly states that all the orbitals are filled, including the 5s orbital before the 4d orbital. Therefore, the correct electron configuration for Palladium, a diamagnetic element, is [Kr] 4d¹⁰.

(c) [Kr] 5s¹4d⁹: The proposed configuration would also suggest an unpaired electron exists in the 4d orbital, which contradicts Palladium being diamagnetic.

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Answer:

8.6 mL

Explanation:

Glacial acetic acid (or anhydrous acetic acid) can be thought of as pure acetic acid, and has a density of 1.05 g/cm³ (or g/mL).

To answer this problem first we convert moles of acetic acid (CH₃CO₂H) to grams, using its molar mass (60 g/mol):

Now we convert grams of acetic acid to mL, using its density:

Answer: 6.7*10^-7 m

Explanation:

The full explanation is shown in the image attached. The energy of the photon is obtained by dividing the bond energy by the Avogadro's number. Using the Plank's equation, we cash obtain the frequency or wavelength of radiation required by substituting into the given equation appropriately.

Final answer:

To calculate the shortest wavelength of light capable of dissociating the Br-I bond, the bond energy given (179 kJ/mol) is first converted to Joules per photon. Then, applying the equation E = hc / λ with Planck's constant and the speed of light gives the shortest wavelength needed to break the bond.

Explanation:

The question asks to calculate the shortest wavelength of light capable of dissociating the Br–I bond in iodine monobromide, given that the bond energy is 179 kJ/mol. To solve this, we apply the equation relating the energy of a photon (E) to its wavelength (λ), using Planck's constant (h) and the speed of light (c).

The energy of the photon needed can be calculated using the equation E = hc / λ, where h = 6.626 x 10-34 J·s (Planck's constant) and c = 3.00 x 108 m/s (speed of light). First, convert the bond dissociation energy from kJ/mol to Joules (J) by multiplying by 1000 and dividing by Avogadro's number (6.022 x 1023 mol-1), giving the energy required per molecule.

Finally, rearrange the equation to solve for λ: λ = hc / E. Plugging in the values, we find the shortest wavelength of light capable of breaking the Br–I bond. Remember, since the question gives the bond dissociation energy in kJ/mol, conversion to Joules is necessary for the calculation to proceed correctly.