A 4.36-g sample of an unknown alkali metal hydroxide is dissolved in 100.0 mL of water. An acid-base indicator is added, and the resulting solution is titrated with 2.50 M HCl(aq) solution. The indicator changes color, signaling that the equivalence point has been reached, after 17.0 mL of the hydrochloric acid solution has been added . What is the identity of the alkali metal cation:
Li+,Na+,K+,Rb+,
or
Cs+?

Answer:

45, 34, 36

Explanation:

The atomic number of Selenium is 34 and the atomic number is 79 also the atom has gained two electron denoted by superscript -2

number of neutrons = mass number - atomic number = 79 - 34 = 45

number of proton = atomic number = 34

number of electron = 34 + 2 = 36. In an atom the number of proton is always equal to number of electron if the atom is neutral but this Se atom has gain two so the number of electron will exceed the number of proton by 2.

The Se ion has 34 protons, 45 neutrons and 36 electrons.

The mass number (A) is given by the sum of the protons and neutrons:

A = protons + neutrons = 79

From the Periodic Table, we can see that the chemical element Selenium (Se) has an atomic number (Z) of 34, which is equal to the number of protons of a chemical element:

Z = protons = 34

Thus, we calculate the number of neutrons as the difference between A and Z:

neutrons = A - Z = 79 - 34 = 45

In a neutral atom (without electric charge), the number of electrons is equal to the number of protons. Since Se ion has 34 protons and a charge of -2, it has 34 electrons to be neutral and then it gained 2 electrons, so the number of electrons is equal to:

electrons = protons + 2 = 34 + 2 = 36

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Answer:

ion - dipole interactions

Explanation:

Ion - dipole interactions -

It refers to the interaction between the ion and a dipole , ( any species which is capable to get produce slight positive and slight negative charge ) , is known as ion - dipole interactions .

Water is a polar compound , and due to more electronegative oxygen atom , it can have slight negative charge and correspondingly , hydrogen atom can attain slight positive charge , and thereby generates a dipole .

Now , from the question,

The salt when dissolved in water , breaks down to ions , cations and anion , and these ions interacts with the polar water molecules , giving rise to the ion - dipole interactions .

The electric potential due to ammonia at a point away along the axis of a dipole is 1.44 [tex]\times[/tex] 10^-5 V.

Explanation:

Given that 1 D = 1 debye unit = 3.34 × 10-30 C-m.

Given p = 1.47 D = 1.47 [tex]\times[/tex] 3.34 [tex]\times[/tex] 10^-30 = 4.90 [tex]\times[/tex] 10^-30.

            V = 1 / (4π∈о)  [tex]\times[/tex]  (p cos(θ)) / (r^2)

where p is a permanent electric dipole,

           ∈ο is permittivity,

            r is the radius from the axis of a dipole,

            V is the electric potential.

        V = 1 / (4 [tex]\times[/tex] 3.14 [tex]\times[/tex] 8.85 [tex]\times[/tex] 10^-12)  [tex]\times[/tex] (4.90 [tex]\times[/tex] 10^-30 [tex]\times[/tex] 1) / (55.3 [tex]\times[/tex] 10^-9)^2

        V  = 1.44 [tex]\times[/tex] 10^-5 V.

Answer:

(a) Amount remaining after 15 days = 27 mg

(b) Amount remaining after t days = [216(0.5)^t/5] mg

Explanation:

Nt = No(0.5)^t/t1/2

No (initial amount) = 216 mg, t = 15 days, t1/2 (half-life) = 5 days

N15 (amount remaining after 15 days) = 216(0.5)^15/5= 216(0.5)^3 = 216 × 0.125 = 27 mg

(b) Nt (amount remaining after t days) = 216(0.5)^t/5

Answer:

(a). 27 mg, (b). N = 216 (1/2)^ (t/5 days).

Explanation:

From the question, we are given that the half-life of bismuth-210, 210Bi = 5 days, a sample mass = 216 mg, the amount remaining after 15 days= ???(unknown).

Using the equation (1) below we can solve for the amount remaining after 15 days.

N= N° (1/2)^(t/th).-------------------------(1).

Where N = is the amount remaining, N° = is the initial amount, t= is time and th= half life.

Therefore,amount remaining, N = 216mg (1/2)^(15 days/5 days).

=====> Amount remaining, N =216 mg (1/2)^3.

=====> Amount remaining, N= 216 mg × 0.125. = 27 mg.

OR

We can solve it by using; 1/2 M°. Where M° is the initial mass.

Therefore, after 5 days, 1/2 × 216 = 108 mg remains.

After 10 days, 1/2 × 108 mg = 54 mg remains.

After 15 days; 1/2 × 54 mg = 27 mg remains.

(b). We are to find the amount remaining after time, t.

The amount remaining after time,t ==> N= N° (1/2)^(t/th)

===> N = 216 (1/2)^ (t/5 days).

With this we can calculate the amount of the sample at particular time if the time is given.

Answer :  The condensed ground-state electron configuration for each is:

(a) [tex][Ar]4s^23d^{2}[/tex]

(b) [tex][Ne]3s^23p^5[/tex]

(c) [tex][Ar]4s^23d^{3}[/tex]

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.

Noble-Gas notation : It is defined as the representation of electron configuration of an element by using the noble gas directly before the element on the periodic table.

(a) The given element is, Ti (Titanium)

As we know that the titanium element belongs to group 4 and the atomic number is, 22

The ground-state electron configuration of Ti is:

[tex]1s^22s^22p^63s^23p^64s^23d^{2}[/tex]

So, the condensed ground-state electron configuration of Ti in noble gas notation will be:

[tex][Ar]4s^23d^{2}[/tex]

There are 4 number of valence electrons shown in orbital diagram.

(b) The given element is, Cl (Chlorine)

As we know that the chlorine element belongs to group 17 and the atomic number is, 17

The ground-state electron configuration of Cl is:

[tex]1s^22s^22p^63s^23p^5[/tex]

So, the condensed ground-state electron configuration of Cl in noble gas notation will be:

[tex][Ne]3s^23p^5[/tex]

There are 7 number of valence electrons shown in orbital diagram.

(c) The given element is, V (Vanadium)

As we know that the vanadium element belongs to group 5 and the atomic number is, 23

The ground-state electron configuration of Ti is:

[tex]1s^22s^22p^63s^23p^64s^23d^{3}[/tex]

So, the condensed ground-state electron configuration of V in noble gas notation will be:

[tex][Ar]4s^23d^{3}[/tex]

There are 5 number of valence electrons shown in orbital diagram.

To draw valence shell electron configurations and orbital diagrams for Ti, Cl, and V, you place electrons in orbitals according to the electron configuration up to the penultimate shell. Titanium's valence shell configuration is [Ar]3d2 4s2, Chlorine's is [Ne]3s2 3p5, and Vanadium's is [Ar]3d3 4s2.

In high school chemistry, understanding electron configurations is fundamental. Here's how you can predict valence shell electron configurations and draw orbital diagrams for titanium (Ti), chlorine (Cl), and vanadium (V).

Titanium has an atomic number of 22. Its electron configuration up to the penultimate shell is [Ar]3d2 4s2. To show the valence electron configuration:

Chlorine has an atomic number of 17. Its electron configuration up to the penultimate shell is [Ne]3s2 3p5. For the valence electrons:

Vanadium has an atomic number of 23. Its electron configuration up to the penultimate shell is [Ar]3d3 4s2. For its valence shell:

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For calculating mass of solution, you need to know the concentration of the -ethyltoluene in the solution and the desired amount of -ethyltoluene. Use the mass percentage to calculate the mass of the solution needed.

The question asks for the mass of solution the chemistry student should use to obtain a certain amount of -ethyltoluene for an experiment. To calculate the mass, we need to know the concentration of the -ethyltoluene in the w/w solution and the desired amount of -ethyltoluene.

Let's assume the concentration of the -ethyltoluene in the solution is given as a mass percentage. If the desired mass of -ethyltoluene is known, we can use the mass percentage to calculate the mass of the solution needed.

For example, if the desired mass of -ethyltoluene is 10 grams and the mass percentage of -ethyltoluene in the solution is 5%, then the mass of the solution needed would be:

Mass of solution = 10 grams / (5% / 100%) = 200 grams

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Answer:

Zn + 2HCl —> ZnCl2 + H2

Explanation:

This is a displacement reaction, in which Zn displaces H2 from acid. The equation for the reaction is given below:

Zn + 2HCl —> ZnCl2 + H2

Answer:

Carbon Dioxide = CO2

Explanation:

The synthesis of Malachite is seen in the chemical formula:

CuSO 4 . 5H2O(aq) + 2NaCO3(aq) --> CuCO 3 Cu(OH) 2 (s) + 2Na 2 SO 4 (aq) + CO 2 (g) + 9H 2 O(l)

The bubbles mentioned in the question hints that our interest is the compounds in their gseous phase  (g).

Upon examining the chemical equation, only CO2 is in the gaseous state and hence the only one that can be formed as bubbles,

The bubbles formed when sodium carbonate is added to the solution of copper sulfate are composed of carbon dioxide (CO2).

When sodium carbonate (Na2CO3) is added to a solution of copper sulfate (CuSO4), bubbles of carbon dioxide (CO2) are formed. The balanced chemical equation for this reaction is:

Na2CO3 + CuSO4 → CuCO3 + Na2SO4

So, the composition of the bubbles formed is carbon dioxide (CO2).

Answer:

Explanation:

Two constitutional isomers of C₂H₇P

1 ) CH₃-CH₂ - PH₂ ( Ethyl phosphane )

2 ) CH₃ - PH - CH₃ ( Dimethyl phosohane )

The chemical formulae of constitutional isomers are the same, but their connectivities differ. Constitutional isomers include ethanol and dimethyl ether, as well as n-butane and isobutane.

Although structural (constitutional) isomers share the same chemical formula, their atoms are bonded in different ways. Stereoisomers share the same atomic configurations and chemical formulae. Only the spatial arrangement of the groups within the molecule separates them from one another.

Compounds with the same chemical formula but different properties are known as isomers. Constitutional isomers are isomers that have different atom connections.

Two constitutional isomers of C₂H₇P

1 ) CH₃-CH₂ - PH₂ ( Ethyl phosphane )

2 ) CH₃ - PH - CH₃ ( Dimethyl phosphane )

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Answer:

The analytical concentrations of thiocyanate ions:

[tex][SCN^-]=0.00012 mol/L[/tex]

The analytical concentrations of ferric ions:

[tex][Fe^{3+}]=0.063 mol/L[/tex]

Explanation:

[tex]Moles (n)=Molarity(M)\times Volume (L)[/tex]

1) Moles of sodium thiocyanate  = n

Volume of sodium thiocyanate solution = 5.00 mL = 0.005 L

(1 mL = 0.001L)

Molarity of the sodium thiocyanate = [tex]4.8\times 10^{-4} M[/tex]

[tex]n=4.8\times 10^{-4} M\times 0.005 L=2.4\times 10^{-6}mol[/tex]

1 mole of sodium thiocyanate has 1 mol of thiocyante ions.

So, moles of thioscyanate ions in [tex]2.4\times 10^{-6}mol[/tex]  of NaSCN.

[tex]=1\times 2.4\times 10^{-6}mol=2.4\times 10^{-6}mol[/tex]

2) Moles of ferric nitrate = n'

Volume of ferric nitrate solution = 2.00 mL = 0.002 L

Molarity of the ferric nitrate = 0.21 M

[tex]n'=0.002 M\times 0.21 L=0.00042 mol[/tex]

1 mole of ferric nitrate has 3 moles of ferric ions.

So number of moles of ferric ions in 0.00042 moles of ferric nitrate is :

[tex]3\times 0.00042 mol=0.00126 mol[/tex]

Volume of nitric acid = 13.00 mL

Total volume by adding all three volumes of solutions = V

V = 5.00 mL + 2.00 mL + 13.00 mL = 20.00 mL = 0.020 L

The analytical concentrations of thiocyanate ions:

[tex][SCN^-]=\frac{2.4\times 10^{-6}mol}{0.020 L}=0.00012 mol/L[/tex]

The analytical concentrations of ferric ions:

[tex][Fe^{3+}]=\frac{0.00126 mol}{0.020 L}=0.063 mol/L[/tex]

Based on the data provided, the analytical concentrations of SC N⁻ and Fe³⁺ in the solution is 1.2 * 10⁻⁴ M and 2.4 * 10⁻² M.

The concentration of a solution is calculated using the formula below:

The moles of the ions are first determined:

moles of NaSC N⁻  in 5.00 mL in 4.8 * 10⁻⁴ is calculated below:

moles of NaSC N⁻  = 0.005 * 4.8 * 10⁻⁴

moles of NaSC N⁻  = 2.4 * 10⁻⁶ moles

1 mole NaSC N ⁻  produces 1 mole SC N⁻

moles of SC N⁻ = 2.4 * 10⁻⁶ moles

moles of Fe(NO₃)₃ in 2.00 mL in 0.21 M solution is calculated below;

moles of Fe(NO₃)₃ = 0.002 * 0.21

moles of Fe(NO₃)₃ = 4.2 * 10⁻⁴ moles

1 mole Fe(NO₃)₃ produces 1 mole Fe³⁺

moles of Fe³⁺ = 4.2 * 10⁻⁴ moles

Total volume of solution = 0.002 + 0.005 + 0.013

Total volume of solution = 0.020 L

Concentration of SC N⁻ = 2.4 * 10⁻⁶/0.020

Concentration of Fe³⁺ = 4.2 * 10⁻⁴/0.02

Therefore, the analytical concentrations of SC N⁻ and Fe³⁺ in the solution is 1.2 * 10⁻⁴ M and 2.4 * 10⁻² M.

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Final answer:

The reaction enthalpy (ΔHrxn) for the combustion of stearic acid is -10500 kJ/mol. When 206 grams of stearic acid are combusted, 7602 kJ of heat is released.

Explanation:

Calculating ΔHrxn for the Combustion of Stearic Acid

The combustion reaction for stearic acid (C₁₈H₃₆O₂) can be written as follows:

C₁₈H₃₆O₂(s) + 26O₂(g) → 18CO₂(g) + 18H₂O(l)

To calculate the reaction enthalpy (ΔHrxn), we use the sum of the enthalpies of formation (ΔHf) of the products minus the sum of ΔHf of reactants:

ΔHrxn = [18(ΔHf of CO₂) + 18(ΔHf of H₂O)] - [ΔHf of stearic acid + 26(ΔHf of O₂)]

Since ΔHf for elemental oxygen (O₂) is zero, we simplify the equation to:

ΔHrxn = [18(-394 kJ/mol) + 18(-242 kJ/mol)] - (-948 kJ/mol)

ΔHrxn = (-7092 kJ/mol + -4356 kJ/mol) - (-948 kJ/mol)

ΔHrxn = -11448 kJ/mol + 948 kJ/mol

ΔHrxn = -10500 kJ/mol

To find the heat (q) released when 206 g of stearic acid reacts, we first convert the mass of stearic acid to moles using its molar mass (284.48 g/mol):

Moles of stearic acid = 206 g / 284.48 g/mol = 0.724 mol

Then, multiply the moles by the ΔHrxn:

q = 0.724 mol * -10500 kJ/mol

q = -7602 kJ

Therefore, 7602 kJ of heat is released in the combustion of 206 g of stearic acid.

Answer:

For A: The value of [tex]K_p[/tex] for the given equation is [tex]1.64\times 10^{-4}[/tex]

For B: The value of [tex]K_p[/tex] for the given equation is 50.2

For C: The value of [tex]K_c[/tex] for the given equation is [tex]5.312\times 10^{-39}[/tex]

For D: The value of [tex]K_c[/tex] for the given equation is [tex]4.60\times 10^{-3}[/tex]

Explanation:

Relation of [tex]K_p[/tex] with [tex]K_c[/tex] is given by the formula:

[tex]K_p=K_c(RT)^{\Delta ng}[/tex]         ..........(1)

where,

[tex]K_p[/tex] = equilibrium constant in terms of partial pressure

[tex]K_c[/tex] = equilibrium constant in terms of concentration

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

[/tex]

T = temperature

[tex]\Delta n_g[/tex] = change in number of moles of gas particles = [tex]n_{products}-n_{reactants}[/tex]

The given chemical equation follows:

[tex]N_2(g)+3H_2(g)\rightleftharpoons 2NH_3(g)[/tex]

We are given:

[tex]K_c=0.50\\T=400^oC=[400+273]K=673K\\\Delta n_g=2-4=-2[/tex]

Putting values in equation 1, we get:

[tex]K_p=0.50\times (0.0821\times 673)^{-2}\\\\K_p=1.64\times 10^{-4}[/tex]

Hence, the value of [tex]K_p[/tex] for the given equation is [tex]1.64\times 10^{-4}[/tex]

The given chemical equation follows:

[tex]H_2(g)+I_2(g)\rightleftharpoons 2HI(g)[/tex]

We are given:

[tex]K_c=50.2\\T=448^oC=[448+273]K=721K\\\Delta n_g=2-2=0[/tex]

Putting values in equation 1, we get:

[tex]K_p=50.2\times (0.0821\times 721)^{0}\\\\K_p=50.2[/tex]

Hence, the value of [tex]K_p[/tex] for the given equation is 50.2

The given chemical equation follows:

[tex]Na_2SO_4.10H_2O(s)\rightleftharpoons Na_2SO_4(s)+10H_2O(g)[/tex]

We are given:

[tex]K_p=4.08\times 10^{-25}\\T=25^oC=[25+273]K=298K\\\Delta n_g=10-0=10[/tex]

Putting values in equation 1, we get:

[tex]4.08\times 10^{-25}=K_c\times (0.0821\times 298)^{10}\\\\K_c=5.312\times 10^{-39}[/tex]

Hence, the value of [tex]K_c[/tex] for the given equation is [tex]5.312\times 10^{-39}[/tex]

The given chemical equation follows:

[tex]H_2O(l)\rightleftharpoons H_2O(g)[/tex]

We are given:

[tex]K_p=0.122\\T=50^oC=[50+273]K=323K\\\Delta n_g=1-0=1[/tex]

Putting values in equation 1, we get:

[tex]0.122=K_c\times (0.0821\times 323)^{1}\\\\K_c=4.60\times 10^{-3}[/tex]

Hence, the value of [tex]K_c[/tex] for the given equation is [tex]4.60\times 10^{-3}[/tex]

Kp and Kc are the equilibrium constant. Kp for A. [tex]1.64 \times 10^{-4}[/tex], for B. 50.2 and Kc for C is [tex]5.312 \times 10^{-39}[/tex] and D. [tex]4.60\times 10^{-3}.[/tex]

Kp is the equilibrium constant given relative to the partial pressure whereas, Kc is given relative to the concentration. The relation between Kp and Kc can be shown as:

[tex]\rm K_{p} = K_{c} (RT)^{\Delta\;ng}[/tex]

For reaction A the balanced reaction is shown as:

[tex]\rm N_{2}(g)+3H_{2}(g) \leftrightharpoons 2NH_{3}(g)[/tex]

The value of Kp is:

[tex]\begin{aligned} \rm K_{p} &= \rm K_{c} (RT)^{\Delta ng}\\\\&= 0.50\times (0.0821\times 673)^{-2}\\\\&= 1.64\times 10^{-4}\end{aligned}[/tex]

Thus, the Kp for A is [tex]1.64\times 10^{-4}.[/tex]

For reaction B the balanced reaction is shown as:

[tex]\rm H_{2} + I_{2} \rightleftharpoons 2HI[/tex]

The value of Kp is:

[tex]\begin{aligned} \rm K_{p} &= \rm K_{c} (RT)^{\Delta ng}\\\\&= 50.2\times (0.0821\times 721)^{0}\\\\&= 50.2 \end{aligned}[/tex]

Thus, the Kp for B is 50.2.

For reaction C the balanced reaction is shown as:

[tex]\rm Na_{2}SO_{4} .10H_{2}O(s) \rightleftharpoons Na_{2}SO_{4}(s)+10H_{2}O(g)[/tex]

The value of Kc is:

[tex]\begin{aligned} \rm K_{p} &= \rm K_{c} (RT)^{\Delta ng}\\\\4.08\times 10^{-25} &= \rm K_{c} \times (0.0821\times 298)^{10}\\\\\rm K_{c} &= 5.312\times 10^{-39} \end{aligned}[/tex]

Thus, the Kc for C is [tex]5.312\times 10^{-39}.[/tex]

For reaction D the balanced reaction is shown as:

[tex]\rm H_{2}O(l) \rightleftharpoons H_{2}O[/tex]

The value of Kc is:

[tex]\begin{aligned} \rm K_{p} &= \rm K_{c} (RT)^{\Delta ng}\\\\0.122 &= \rm K_{c} \times (0.0821\times 323)^{1}\\\\\rm K_{c} &= 4.60\times 10^{-3} \end{aligned}[/tex]

Thus, the Kc for D is [tex]4.60\times 10^{-3}.[/tex]

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Answer:

35.5 % NaCl

Explanation:

Total mass of mixture = 30.126 g

Mass of sand = 15.976 g

Mass of iron = 3.455 g

Mass of NaCl = ? → Total mass - 15.976 g - 3.455 g = 10.695 g

% mass of NaCl in the sample → (Mass of NaCl / Total mass) . 100

(10.695 g / 30.126 g) . 100 = 35.5 %

Answer:

The van't Hoff factor of the solute is 1.51

Explanation:

Step 1: Data given

Molality = 0.710 molal

The aqueous solution freezes at − 2.00°C

Freezing point depression constant of water = 1.86 °C/m

Step 2: Calculate the van't Hoff factor

ΔT = i*Kf * m

⇒ with ΔT = The difference between the feezing point of pure and solution = 2.00°C

⇒ i the van't Hoff factor = TO BE DETERMINED

⇒ Kf = Freezing point depression constant of water = 1.86 °C/m

⇒ m = the molality of the solution = 0.710 molal

2.00 = i * 1.86 * 0.710

i = 1.51

The van't Hoff factor of the solute is 1.51

Final answer:

To find the van't Hoff factor for a solution that freezes at − 2.00°C with a molality of 0.710m, the van't Hoff factor, i, is approximately calculated as 1.52, indicating dissociation into multiple particles.

Explanation:

To calculate the van't Hoff factor, i, for the solute in a 0.710 m aqueous solution that freezes at − 2.00 ℃, we use the formula for freezing point depression, ΔTf = iKfm, where ΔTf is the freezing point depression, Kf is the molal freezing-point depression constant for the solvent (water in this case, with a value of − 1.86°C/m), and m is the molality of the solution. First, understand that the freezing point of pure water is 0°C, and the solution's freezing point is − 2.00°C, so the depression, ΔTf, is 2.00°C. To find the van't Hoff factor, i, rearrange the equation to i = ΔTf / (Kfm). Substituting the values gives us i = 2.00 °C / (− 1.86°C/m × 0.710 m) = 2.00°C / − 1.32°C = − 1.52. However, since i should be a positive value and considering the potential rounding or measurement error, the magnitude is taken yielding i approximately equal to 1.52, reflecting the number of particles the solute dissociates into in solution.

Answer:

1. Gender role

2. Sex

Explanation:

Answer:

(a) 5s. n = 5. Sublevel s, l = 0. Number of orbitals = 1

(b) 3p. n = 3. Sublevel p, l = 1. Number of orbitals = 3

(c) 4f. n =4. Sublevel f, l = 3. Number of orbitals = 7

Explanation:

The rules for electron quantum numbers are:

1. Shell number, 1 ≤ n

2. Sublevel number, 0 ≤ l ≤ n − 1

So,

(a) 5s. n = 5, shell number 5. Sublevel s, l = 0. Number of orbitals = 2l +1 = 1

(b) 3p. n = 3, shell number 3. Sublevel p, l = 1. Number of orbitals = 2l +1 = 3

(c) 4f. n =4, shell number 4. Sublevel f, l = 3. Number of orbitals =  2l +1 = 7

The 5s sublevel has n=5 and l=0 with 1 orbital, the 3p sublevel has n=3 and l=1 with 3 orbitals, and the 4f sublevel has n=4 and l=3 with 7 orbitals.

For the sublevels given, the corresponding quantum numbers and the number of orbitals are as follows:

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Answer: The theoretical yield and percent yield of [tex][Co(NH_3)_4(H_2O)_2]Cl_2[/tex] is 3.93 g and 30.53 % respectively

Explanation:

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

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]     .....(1)

Given mass of [tex]CoCl_2.6H_2O[/tex] = 4.00 g

Molar mass of [tex]CoCl_2.6H_2O[/tex] = 238 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of }CoCl_2.6H_2O=\frac{4.00g}{238g/mol}=0.0168mol[/tex]

The chemical equation for the reaction of [tex]CoCl_2.6H_2O[/tex] to form  [tex][Co(NH_3)_4(H_2O)_2]Cl_2[/tex] follows:

[tex]CoCl_2.6H_2O+4NH_3\rightarrow [Co(NH_3)_4(H_2O)_2]Cl_2+4H_2O[/tex]

By Stoichiometry of the reaction:

1 mole of [tex]CoCl_2.6H_2O[/tex] produces 1 mole of [tex][Co(NH_3)_4(H_2O)_2]Cl_2[/tex]

So, 0.0168 moles of [tex]CoCl_2.6H_2O[/tex] will produce = [tex]\frac{1}{1}\times 0.0168=0.0168mol[/tex] of [tex][Co(NH_3)_4(H_2O)_2]Cl_2[/tex]

Now, calculating the mass of [tex][Co(NH_3)_4(H_2O)_2]Cl_2[/tex] from equation 1, we get:

Molar mass of [tex][Co(NH_3)_4(H_2O)_2]Cl_2[/tex] = 234 g/mol

Moles of [tex][Co(NH_3)_4(H_2O)_2]Cl_2[/tex] = 0.0168 moles

Putting values in equation 1, we get:

[tex]0.0168mol=\frac{\text{Mass of }[Co(NH_3)_4(H_2O)_2]Cl_2}{234g/mol}\\\\\text{Mass of }[Co(NH_3)_4(H_2O)_2]Cl_2=(0.0168mol\times 234g/mol)=3.93g[/tex]

To calculate the percentage yield of [tex][Co(NH_3)_4(H_2O)_2]Cl_2[/tex], we use the equation:

[tex]\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100[/tex]

Experimental yield of [tex][Co(NH_3)_4(H_2O)_2]Cl_2[/tex] = 1.20 g

Theoretical yield of [tex][Co(NH_3)_4(H_2O)_2]Cl_2[/tex] = 3.93 g

Putting values in above equation, we get:

[tex]\%\text{ yield of }[Co(NH_3)_4(H_2O)_2]Cl_2=\frac{1.20g}{3.93g}\times 100\\\\\% \text{yield of }[Co(NH_3)_4(H_2O)_2]Cl_2=30.53\%[/tex]

Hence, the theoretical yield and percent yield of [tex][Co(NH_3)_4(H_2O)_2]Cl_2[/tex] is 3.93 g and 30.53 % respectively

Answer : The pH will be, 3.2

Explanation :

As we known that the value of solubility constant of ferric hydroxide at [tex]25^oC[/tex] is, [tex]2.79\times 10^{-39}[/tex]

Amount or solubility of iron consumed = (1.800 - 0.3) mg/L = 1.5 mg/L

The given solubility of iron convert from mg/L to mol/L.

[tex]1.5mg/L=\frac{1.5\times 10^{-3}g/L}{56g/mol}=2.7\times 10^{-7}mol/L[/tex]

The chemical reaction will be:

[tex]Fe(OH)_3\rightarrow Fe^{3+}+3OH^-[/tex]

The expression of solubility constant will be:

[tex]K_{sp}=[Fe^{3+}]\times [3OH^-]^3[/tex]

Now put all the given values in this expression, we get the concentration of hydroxide ion.

[tex]2.79\times 10^{-39}=(2.7\times 10^{-7})\times [3OH^-]^3[/tex]

[tex][OH^-]=1.5\times 10^{-11}M[/tex]

Now we have to calculate the pOH.

[tex]pOH=-\log [OH^-][/tex]

[tex]pOH=-\log (1.5\times 10^{-11})[/tex]

[tex]pOH=10.8[/tex]

Now we have to calculate the pH.

[tex]pH+pOH=14\\\\pH=14-pOH\\\\pH=14-10.8\\\\pH=3.2[/tex]

Therefore, the pH will be, 3.2

To precipitate all but 0.3 mg/L of iron, the pH must be raised to a certain value. This can be calculated by using the solubility product constant (Ksp) and the balanced equation for the precipitation reaction. By solving for pOH and then pH, we can determine the pH at which the majority of the iron will precipitate.

To calculate the pH at which all but 0.3 mg/L of iron will precipitate, we can use the solubility product constant (Ksp) of the iron precipitate. The balanced equation for the precipitation reaction is:

Fe(OH)3(s) ⇌ Fe3+(aq) + 3OH-(aq)

The Ksp expression for this reaction is:

Ksp = [Fe3+][OH-]^3

Assuming that Fe(OH)3 is the only significant source of Fe3+ ions, we can set up an equilibrium expression:

[Fe3+] = Ksp / [OH-]^3

Given that the concentration of Fe3+ ions we want to achieve is 0.3 mg/L, we can substitute this value and solve for the hydroxide ion concentration:

[OH-]^3 = Ksp / [Fe3+]

Since Fe(OH)3 is an amphoteric hydroxide and can behave as both an acid and a base, we can assume that the hydroxide ion concentration is equal to the concentration of the hydroxide ion from water:

[OH-] = 10^(-pOH)

Plugging in the values, we get:

(10^(-pOH))^3 = Ksp / [Fe3+]

Simplifying, we obtain:

10^(-3pOH) = Ksp / [Fe3+]

Taking the logarithm of both sides:

-3pOH = log(Ksp / [Fe3+])

Rearranging the equation and solving for pOH:

pOH = -log(Ksp / [Fe3+]) / 3

To find the pH, we can use the relationship:

pH + pOH = 14

Substituting the pOH value we obtained above:

pH = 14 - pOH

Now we can substitute the given values and calculate the pH at which the majority of iron will precipitate.

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Answer:

The final volume will be 5.80 L

Explanation:

Step 1: Data given

Number of moles gas = 0.140 moles

Volume of gas = 2.78 L

Number of moles added = 0.152 moles

Step 2: Calculate the final volume

V1/n1 = V2/n2

⇒ with V1 = the initial volume = 2.78 L

⇒ with n1 = the initial number of moles = 0.140 moles

⇒ with  V2 = The new volume = TO BE DETERMINED

⇒ with n2 = the new number of moles = 0.140 + 0.152 = 0.292 moles

2.78/0.140 = V2 /0.292

V2 = 5.80 L

The final volume will be 5.80 L

Charge of the electron: [tex]-2.3\cdot 10^{-19}C[/tex]

Explanation:

In Millikan experiment, it was discovered that the electric charge on the oil drops is discrete - and its value is always an integer multiple of a certain charge [tex]e[/tex], called fundamental charge (the charge of the electron). This is because an oil drop always contains an integer number of electrons, so the charge must be a multiple of [tex]e[/tex].

This means that we can write the charge on an oil drop as

[tex]Q=Ne[/tex]

For the drop recorded in this experiment, we have:

[tex]Q_A = N_A e = -6.9\cdot 10^{-19}C[/tex]

[tex]Q_B = N_B e = -9.2\cdot 10^{-19}C[/tex]

[tex]Q_C = N_C e = -11.5\cdot 10^{-19}C[/tex]

[tex]Q_D = N_D e = -4.6\cdot 10^{-19}C[/tex]

By dividing drop A by drop D, we get

[tex]\frac{Q_A}{Q_D}=\frac{3}{2}[/tex]

Also by dividing deop B by drop D we get

[tex]\frac{Q_B}{Q_D}=\frac{4}{2}[/tex]

And also, by dividing drop C by drop D we get

[tex]\frac{Q_C}{Q_D}=\frac{5}{2}[/tex]

This means that the charges on drop A, B, C and D are in the ratio

3 : 4 : 5 : 2

And therefore, the fundamental charge must be half of the charge on drop D:

[tex]e=\frac{Q_D}{2}=-2.3\cdot 10^{-19}C[/tex]

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Answer:

94.3 grams

Explanation:

MW of C2HF3O2 is 114g/mol

MW of oxygen in C2HF3O2 is 32g/mol

% composition of oxygen in C2HF3O2 = 32/114 × 100 = 28.1%

Mass of oxygen = 26.5 grams

Mass of trifluoroacetic acid = 26.5/0.281 = 94.3 grams

In the given question, 185.39 g is the mass of the trifluoroacetic acid sample.

Mass is a measure of the amount of matter in an object. The standard metric unit of mass is the kilogram (kg) and grams (gm).

To calculate the mass of the trifluoroacetic acid sample, we need to determine the molar mass of trifluoroacetic acid and then use the given mass of oxygen to find the mass of the entire compound.

The molar mass of trifluoroacetic acid ([tex]\rm C_2HF_3O_2[/tex]) can be calculated by summing the atomic masses of its constituent elements:

Molar mass of [tex]\rm C_2HF_3O_2[/tex] = (2 × 12.01 g/mol) + (1 × 1.01 g/mol) + (3 × 18.99 g/mol) + (2 × 16.00 g/mol)

= 112.03 g/mol

Now, we can use the given mass of oxygen (26.5 g) to find the mass of the entire trifluoroacetic acid sample.

mass (g) = (26.5 g) / (molar mass of O)

mass (g) = (26.5 g) / (16.00 g/mol)

mass (g) = 1.65625 mol

Finally, we can convert moles to grams using the molar mass of trifluoroacetic acid:

mass (g) = 1.65625 mol × 112.03 g/mol

mass (g) = 185.39 g

Therefore, the mass of the trifluoroacetic acid sample is approximately 185.39 g.

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In the given chemical equation, zinc is undergoing reduction as it gains electrons.

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .

The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.

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Answer:

A

Explanation:

A volcanic eruption affects the Earth's atmosphere mainly through the release of ash and poisonous gases. These materials can impact global climate, air travel, human health, and regional weather patterns.

A volcanic eruption impacts the Earth's atmosphere in a number of ways, largely through the release of volcanic gases and ash. The most significant aspect is option A, eruptions shooting out ash and poisonous gases into the air.

These gases, including sulfur dioxide, can contribute to the formation of aerosols in the higher layers of the atmosphere, potentially affecting global climate patterns. For example, a large volcanic eruption can lead to cooler temperatures worldwide for a few years.

Additionally, the ash particles ejected during a volcanic eruption can have a range of effects, from impacting air travel to affecting human health and altering regional weather patterns.

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To find the number of photons per second that illuminate a book from a 75-W bulb, calculate 5% of the bulb's power for light, take 10% of that for the light on the book, then divide by the energy per photon. The result is approximately 1.04 x 10¹⁸ photons per second.

The student's question is about determining the number of photons per second that shine on a chemistry text from a 75-Watt incandescent bulb, with only 5% of the bulb's power output converting to light and just 10% of that light illuminating the book.

To calculate this, we first determine the total light power output by taking 5% of the bulb's power, which gives us 3.75 Watts (0.05 times 75 W). Next, we need to calculate the power that actually falls on the book, which is 10% of the light power output, or 0.375 Watts. The energy per photon can be calculated using the formula E = (hc)/λ, where 'h' is Planck's constant, 'c' is the speed of light, and 'λ' is the wavelength. For 550 nm (550 x 10-9 meters), the energy per photon is approximately 3.61 x 10⁻¹⁹ Joules. Finally, to find the number of photons per second, we divide the light power on the book by the energy per photon: 0.375 J/s times 1 photon/3.61 x 10⁻¹⁹ J, resulting in approximately 1.04 x 10¹⁸ photons per second.

Answer:

Explanation: i)  Mass per capacity of the tant = (0.15015/100100) kg/L = 0.0000015 kg/L

Amount salt of concentrated salt left = ( 0.03003 - 0.0000015) kg/L = 0.0300285 kg/L

∴  mass of salt in the tank = 0.0300285 kg/L X 77 L/min = 2.31 kg

ii) Capacity of tank at 0.01001 kg/L: 2.31 kg/0.01001 kg/L = 230.77 L

∴ time taken for the concentration of the salt = 230.77/(77 L/min) = 3 minutes.

Answer : The pH of the solution is, 5.22

Explanation :

First we have to calculate the moles of acetic acid and sodium acetate.

[tex]\text{Moles of acetic acid}=\text{Concentration of acetic acid}\times \text{Volume of acetic acid}=0.01M\times 0.025L=0.00025mol[/tex]

and,

[tex]\text{Moles of sodium acetate}=\text{Concentration of sodium acetate}\times \text{Volume of sodium acetate}=0.03M\times 0.025L=0.00075mol[/tex]

Now we have to calculate the concentration of acetic acid and sodium acetate in 1 L of solution.

[tex]\text{Concentration of acetic acid}=\frac{\text{Moles of acetic acid}}{\text{Volume of solution}}=\frac{0.00025mol}{1L}=0.00025M[/tex]

and,

[tex]\text{Concentration of sodium acetate}=\frac{\text{Moles of sodium acetate}}{\text{Volume of solution}}=\frac{0.00075mol}{1L}=0.00075M[/tex]

Now we have to calculate the pH of the solution.

Using Henderson Hesselbach equation :

[tex]pH=pK_a+\log \frac{[Salt]}{[Acid]}[/tex]

[tex]pH=pK_a+\log \frac{[\text{Sodium acetate}]}{[\text{Acetic acid}]}[/tex]

[tex]pK_a[/tex]  of acetic acid = 4.74

Now put all the given values in this expression, we get:

[tex]pH=4.74+\log (\frac{0.00075}{0.00025})[/tex]

[tex]pH=5.22[/tex]

Thus, the pH of the solution is, 5.22

To find the pH of the solution, calculate the concentration of the acetic acid and sodium acetate. Convert the volume of acetic acid and sodium acetate to liters. Use the Henderson-Hasselbalch equation to find the pH of the buffer solution.

To determine the pH of the solution, we need to calculate the concentration of the acetic acid and its conjugate base, sodium acetate. First, convert the volume of acetic acid and sodium acetate to liters. The concentration of acetic acid is 0.01 M (10 mM), and the concentration of sodium acetate is 0.03 M (30 mM). Next, calculate the moles of acetic acid and sodium acetate using the equation moles = concentration x volume. The moles of acetic acid are 0.01 moles, and the moles of sodium acetate are 0.03 moles. The solution contains a weak acid (acetic acid) and its conjugate base (sodium acetate), which makes it a buffer solution. To find the pH of a buffer solution, we need to use the Henderson-Hasselbalch equation: pH = pKa + log ([base]/[acid]). The pKa of acetic acid is 4.74. Substitute the values into the equation: pH = 4.74 + log (0.03/0.01) = 4.74 + log(3) = 4.74 + 0.48 = 5.22. Therefore, the pH of the 1-L solution is 5.22.

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Given the pKa values of serine's α‑carboxyl and α‑amino groups, the carboxyl group is fully ionized and carries a -1 charge while the amino group carries a +1 charge at a pH of 8.80. Therefore, the total net charge on serine at this pH is zero.

Your question asks to calculate the average net charge on the amino acid serine at a pH of 8.80, given the pKa values for the α‑carboxyl group (2.21) and the α‑amino group (9.15). This is related to the concept of acid dissociation constants (pKa) and buffer solutions in chemistry.

At a pH of 8.80, the pH is higher than the pKa of the α‑carboxyl group but lower than the pKa of the amino group. For the α‑carboxyl group whose pKa is 2.21, the pH is significantly higher. This means, it is fully ionized and carries a -1 charge.

On the other hand, the α‑amino group has a pKa of 9.15, which is higher than the pH of 8.80. This means it is predominantly in its protonated form and carries a +1 charge.

Therefore, the total charge on serine at this pH is the sum of the charges of the α‑carboxyl group and the α‑amino group, which is -1 + 1 = 0. Hence, the average net charge of serine in a solution with pH 8.80 is zero.

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The question is incomplete, here is the complete question:

Calculate the pH at of a 0.10 M solution of anilinium chloride [tex](C_6H_5NH_3Cl)[/tex] . Note that aniline [tex](C6H5NH2)[/tex] is a weak base with a [tex]pK_b[/tex] of 4.87. Round your answer to 1 decimal place.

Answer: The pH of the solution is 5.1

Explanation:

Anilinium chloride is the salt formed by the combination of a weak base (aniline) and a strong acid (HCl).

To calculate the pH of the solution, we use the equation:

[tex]pH=7-\frac{1}{2}[pK_b+\log C][/tex]

where,

[tex]pK_b[/tex] = negative logarithm of weak base which is aniline = 4.87

C = concentration of the salt = 0.10 M

Putting values in above equation, we get:

[tex]pH=7-\frac{1}{2}[4.87+\log (0.10)]\\\\pH=5.06=5.1[/tex]

Hence, the pH of the solution is 5.1

The pH of the solution is 5.1.

Anilinium chloride refers to the salt that should be created by the combination of a weak base (aniline) and a strong acid (HCl).

here the following equation should be used.

ph = 7-1/2(pkb+ logc)

here pkb = negative logarithm of the weak base i.e. aniline = 4.87

And, C = concentration of the salt = 0.10 M

Now the ph should be

= 7-1/2(4.87 + log(0.10))

= 5.1

Hence, The pH of the solution is 5.1.

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Answer: The major product of the reaction between Hydrobromic Acid and 2-bromo-1-butene in the presence of ether and acid is 2,2-dibromobutane.

Explanation:

The mechanism of the reaction is supported by the Markovnikov's rule which explains that in the addition reaction of alkenes by hydrogen-halogen compounds, the incoming halogen substituent goes to the more substituted Carbon. It can also be stated that incoming hydrogen atom goes to the Carbon with more Hydrogen atoms.

The only case when the reverse of Markovnikov's rule takes place is when Hydrogen peroxide is present and the addition reagent is HBr.

This case is not like that and it simply follows the Markovnikov's rule.

I'll add an attachment of the reaction to this now.

Answer:

On the reaction the product is 2-2-dibromobutane.

Explanation:

2-Bromo-1 butene is given as in the figure. On the breaking of the double bond 2 local electrophilic and nucleophilic radicals will be formed in the 2-Bromo-1-butene and H-Br respectively.

Due to the Markovnikov Rule the nucleophilic radical of the attacking compound bonds with the carbon atom with least number of H atoms so the product formed will be 2-2-dibromobutane as indicated in the figure.

Answer:

[tex]\large \boxed{\text{0.012 mol}}[/tex]  

Explanation:

We will need a balanced equation with moles, so let's gather all the information in one place.

               CH₃C₆H₄NH₂·HCl + (CH₃CO)₂O ⟶ CH₃C₆H₄NHCOCH₃ + junk

V/mL:                    70.

c/mol·L⁻¹:             0.167

For simplicity in writing , let's call p-toluidine hydrochloride A and N-acetyl-p-toluidine B.

The equation is then

A + Ac₂O ⟶ B + junk

1. Moles of A

[tex]\text{Moles of A} = \text{70. mL A}\times \dfrac{\text{0.167 mmol A}}{\text{1 mL A}}= \text{12 mmol A}[/tex]

2. Moles of B

The molar ratio is 1 mol B:1 mol A

Moles of B = moles of A = 12 mmol = 0.012 mol

[tex]\text{You can prepare $\large \boxed{\textbf{0.012 mol}}$ of N-acetyl-p-toluidine. }[/tex]