A sodium atom has a mass number of 23. Its atomic number is 11. How many electrons does a neutral sodium atom have?

Explanation:

Formula according to the radius ratio rule is as follows.

             [tex]\frac{r_{+}}{r_{-}} = \frac{73}{184}[/tex]

                          = 0.397

According to the radius ratio rule, as the calculated value is 0.397 and it lies in between 0.225 to 0.414. Therefore, it means that the type of void is tetrahedral.

Thus, we can conclude that the given compound is most likely to adopt closest-packed array with lithium ions occupying tetrahedral holes.

Answer:

closest-packed array with lithium ions occupying tetrahedral holes

Explanation:

Given the small size of lithium ions and that they are present in twice the amount as selenide ions, they must occupy tetrahedral holes in a closest-packed array.

Answer:

12.4×10^3 V

Explanation:

From E=hc/wavelength= eV

The voltage becomes

V= hc/e* wavelength

V= 6.63*10^-34*3*10^8/1.6*10^-19*1*10^-10

Note that the energy of the photon is transferred to the electron. That is the basic assumption we have applied in solving this problem. The kinetic energy of the electron is equal to the product of the electron charge and the acceleration potential.

When the plate separation of a charged parallel-plate capacitor is doubled, the stored energy becomes one-half as large due to the inverse relationship between capacitance and the distance between plates.

When a parallel-plate capacitor is disconnected from a battery and the plate separation is doubled, the stored energy changes in the following manner: The stored energy becomes one-half as large. This happens because the energy (U) stored in a capacitor is given by U = (1/2)CV2, where C is the capacitance and V is the voltage across the plates. When the capacitor is disconnected from the battery, the charge Q and voltage V across the plates remain constant.

However, the capacitance C of a parallel-plate capacitor is directly proportional to the area of the plates (A) and inversely proportional to the distance (d) between them, as given by C = ε0A/d, where ε0 is the vacuum permittivity. When distance d is doubled, capacitance C is halved, therefore, the energy stored, which is proportional to C, also halves because it is dependent on the capacitance.

Answer:

At least 3 three extractions are required to recover at least 99.5 % of the material in the organic layer.

Explanation:

The partition coefficient of a solute (S) soluble in two immiscible solvents is given by the following formula

[tex]K_S=\frac{[S]_2}{[S]_1}[/tex]

The lower layer is taken as an aqueous layer (1), while the upper layer is organic (2). The fraction of solute remaining in the aqueous layer is given by the following formula

[tex]q^n=(\frac{V_1}{V_1 \times KV_2})^n[/tex]

Here, n denotes the number of extraction, and q^n represents the fraction of solute remaining in aqueous solvent after n number of extraction. According to the given data, the fraction of solute remaining in the aqueous layer after multiple extractions is 0.005, i.e., q^n=0.005. Mathematically,

[tex]0.005=(\frac{50}{50 + 50\times10})^n\\\\0.005=(0.091)^n[/tex]

Taking log on both sides

[tex]log(0.005)=nlog(0.091)[/tex]

[tex]log(0.005)=nlog(0.091)\\\\-2.301=-n1.04\\n=2.21[/tex]

The above calculations show that the number of extractions should be greater than 2, i.e, at least 3, in order to achieve extraction greater than 99.5 %.

With a partition coefficient of 10 and using 50mL each of water and ether, approximately three extractions are required to recover at least 99.5% of the material in the organic layer.

This question relates to an extraction process used in chemistry. The extraction process is governed by a partition coefficient, which is the ratio of the concentrations of a compound in the two solvents (organic layer and water in this case) at equilibrium. To calculate the number of extractions required to recover at least 99.5% of the material, we can use the formula:

Where D is the partition coefficient. By rearranging this equation, we get:

Substituting the given values into the equation, we find that approximately 3 extractions would be required in order to recover at least 99.5% of the material in the organic layer.

https://brainly.com/question/14653083

#SPJ3

Answer:

For a: The charge on the ion formed is +3

For b: The charge on the ion formed is -2

For c: The charge on the ion formed is +2

Explanation:

An ion is formed when an atom looses or gains electron.

For the given options:

Aluminium is the 13th element of the periodic table having electronic configuration of [tex]1s^22s^22p^63s^23p^1[/tex]

This element will loose 3 electrons to form [tex]Al^{3+}[/tex] ion

The charge on the ion formed is +3

Sulfur is the 16th element of the periodic table having electronic configuration of [tex]1s^22s^22p^63s^23p^4[/tex]

This element will gain 2 electrons to form [tex]S^{2-}[/tex] ion

The charge on the ion formed is -2

Strontium is the 38th element of the periodic table having electronic configuration of [tex]1s^22s^22p^63s^23p^64s^23d^{10}4p^65s^2[/tex]

This element will loose 2 electrons to form [tex]Sr^{2+}[/tex] ion

The charge on the ion formed is +2

Answer:

Part A:

Charge is [tex]P^{3-}[/tex]

Configuration is [tex]1s^2 2s^22p^63s^23p^6[/tex]

Part B:

Charge is [tex]Mg^{2+}[/tex]

Configuration is [tex]1s^2 2s^22p^6[/tex]

Part C:

Charge is [tex]Se^{2-}[/tex]

Configuration is [tex]1s^2 2s^22p^63s^23p^64s^23d^{10}4p^6[/tex]

Explanation:

Monatomic ions:

These ions consist of only one atom. If they have more than one atom then they are poly atomic ions.

Examples of Mono Atomic ions: [tex]Na^+, Cl^-, Ca^2^+[/tex]

Part A:

For P:

Phosphorous (P) has 15 electrons so it require 3 more electrons to stabilize itself.

Charge is [tex]P^{3-}[/tex]

Full ground-state electron configuration of the mono atomic ion:

[tex]1s^2 2s^22p^63s^23p^6[/tex]

Part B:

For Mg:

Magnesium (Mg) has 12 electrons so it requires 2 electrons to lose to achieve stable configuration.

Charge is [tex]Mg^{2+}[/tex]

Full ground-state electron configuration of the mono atomic ion:

[tex]1s^2 2s^22p^6[/tex]

Part C:

For Se:

Selenium (Se) has 34 electrons and requires two electrons to be stable.

Charge is [tex]Se^{2-}[/tex]

Full ground-state electron configuration of the mono atomic ion:

[tex]1s^2 2s^22p^63s^23p^64s^23d^{10}4p^6[/tex]

The electron configuration of atoms or ions depends on the number of electrons present.

The electron configuration refers to the arrangement of electrons in an atom or ions. Electrons are arranged in energy levels and each energy level is composed of orbitals.

The monoatomic ion most likely formed by P is P^3-. The electron configuration of this ion is 1s2 2s2 2p6 3s2 3p6. This is because P is in group 15 and attains a stable octet by gaining three electrons.

The monoatomic ion most likely formed by Mg is Mg^2+. Mg is a group 2 element and attains a stable octet by loss of two electrons. The electron configuration of this ion is 1s² 2s² 2p^6.

Se is a group 16 element, the monoatomic ion formed by Se is Se^2-. Se attains a stable octet by gain of two electrons. The electron configuration of this ion is; 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6.

Learn more: https://brainly.com/question/5624100

Answer:

The reaction of hex-3-yne with one equivalent of HCl Is an Anti addition, see in the drawing the major product.

Explanation:

The mechanism of the reaction proceeds through a carbocation, formed in the most substituted carbon of the triple bond,  in this case it is indistinct because the triple bond is in the central carbons. Therefore, it is a regioselective reaction that follows Markovnikov's rule, adding the halogen to the more substituted carbon of the alkyne.

The anti addition consists in the addition of two substituents on opposite sides of a triple bond, which gives it greater stability.

Answer:

2.33 M is the molarity of sodium ions in a solution prepared by mixing.

Explanation:

[tex]Molarity=\frac{n}{V(L)}[/tex]

n = moles of substance

V = Volume of solution in L

In, 236 ml of 0.75 M sodium phosphate :

Moles of sodium phosphate = n

Volume of sodium phosphate solution = V = 236 mL = 0.236 L(1 m L =0.001 L)

Molarity of the solution = M = 0.75 M

[tex]n=M\times V=0.75 M\times 0.236 L=0.177 mol[/tex]

Sodium phosphate = [tex]Na_3PO_4[/tex]

1 mole of sodium phosphate has 3 mol of sodium ions.

Then 0.177 moles will have = 0.177 mol × 3 = 0.531 mol

In, 252.8 ml of 1.2 M sodium sulfide:

Moles of sodium sulfide = n'

Volume of sodium sulfide solution = V' = 252.8 mL = 0.2528 L(1 m L =0.001 L)

Molarity of the solution = M' = 1.2 M

[tex]n'=M'\times V'=1.2 M\times 0.2528 L=0.30336 mol[/tex]

Sodium sulfide= [tex]Na_2S[/tex]

1 mole of sodium sulfide has 2 mol of sodium ions.

Then 0.30336 moles will have = 0.30336 mol × 2 = 0.60672 mol

After mixing both solutions:

Moles of sodium ions = 0.60672 mol + 0.531 mol = 1.13772 mol

Volume of the mixture = 0.2528 L = 0.236 L = 0.4888 L

Molarity of sodium ions:

[tex]=\frac{1.13772 mol}{0.4888 L}=2.3275 M\approx 2.33 M[/tex]

2.33 M is the molarity of sodium ions in a solution prepared by mixing.

The molarity of sodium ion, Na⁺ in the resulting solution is 2.33 M

We'll begin by calculating the number of mole of sodium ion, Na⁺ in each solution.

For Na₃PO₄:

Volume = 236 mL = 236 / 1000 = 0.236 L

Molarity = 0.75 M

Mole = Molarity x Volume

Mole of Na₃PO₄ = 0.75 × 0.236

Na₃PO₄(aq) —> 3Na⁺(aq) + PO₄³¯(aq)

From the balanced equation above,

1 mole of Na₃PO₄ contains 3 mole of Na⁺

Therefore,

0.177 mole of Na₃PO₄ will also contain = 0.177 × 3 = 0.531 mole of Na⁺

Thus, 0.531 mole of Na⁺ is present in 480 mL of 0.75 M Na₃PO₄

For Na₂S:

Volume = 252.8 mL = 252.8 / 1000 = 0.2528 L

Molarity = 1.2 M

Mole = Molarity x Volume

Mole of Na₂S = 1.2 × 0.2528

Na₂S(aq) —> 2Na⁺(aq) + S²¯(aq)

From the balanced equation above,

1 mole of Na₂S contains 2 moles of Na⁺

Therefore,

0.30336 mole of Na₂S will contain = 0.30336 × 2 = 0.60672 mole of Na⁺

Thus, 0.60672 mole of Na⁺ is present in 252.8 mL of 1.2 M Na₂S

Mole of Na⁺ in Na₃PO₄ = 0.531 mole

Mole of Na⁺ in Na₂S = 0.60672 mole

Total mole = 0.531 + 0.60672

Volume of Na₃PO₄ = 0.236 L

Volume of Na₂S = 0.2528 L

Total volume = 0.236 + 0.2528

Total mole = 1.13772 mole

Total volume = 0.4888 L

Molarity = mole / Volume

Molarity of Na⁺ = 1.13772 / 0.4888

Therefore, the molarity of sodium ion, Na⁺ in the resulting solution is 2.33 M

Learn more: https://brainly.com/question/25653729

Answer and Explanation

The isomer picked is the N-Propylamine.

It has a lone pair of electron available on the electron rich Nitrogen and no formal charge.

Since it will be hard to draw the Lewis structure in this answer format, I'll attach a picture of the Lewis structure to this answer.

The lone pair of electron is shown by the two dots on the Nitrogen atom.

The Lewis structure for propylamine is drawn by connecting a chain of three carbon atoms with the appropriate number of hydrogen atoms, and attaching the nitrogen atom to the third carbon with two of its own hydrogen atoms and a lone pair, ensuring all atoms follow the octet rule without any formal charges.

To draw the Lewis structure for propylamine (CH₃(CH₂)₂NH₂), you should follow the basic rules of drawing Lewis structures and consider the number of valence electrons that each atom has. Carbon (C) has 4 valence electrons, Hydrogen (H) has 1, and Nitrogen (N) has 5. Here's the step-by-step breakdown:

In propylamine, no formal charges are present as all the atoms have the correct number of electrons around them for neutrality. The nitrogen atom has a free lone pair and there are no pi bonds, so each bond is a single bond.

The alkali metal cation in the unknown metal hydroxide that has been reacted with hydrochloric acid is Potassium (K+). The identity of the cation was determined by performing a stoichiometric calculation based on the balanced chemical reaction and the molar masses of the alkali metal hydroxide.

This is a stoichiometry problem that requires understanding of acid-base titration reactions. In a neutralization reaction, an acid reacts with a base to form water plus a salt. Here, the hydrochloric acid (HCl) is reacting with the alkali metal hydroxide (MOH) to form water (H2O) and a salt (MCl). The balanced chemical reaction is HCl + MOH -> H2O + MCl.

The mole ratio between HCl and MOH in this reaction is 1:1. This means that for each mole of HCl used, one mole of MOH will react. From the volume (17.0 mL) and molarity (2.5 M) of HCl used, we can calculate the number of moles of HCl, which will also be the number of moles of MOH because of the 1:1 mole ratio.

mol HCl = Molarity x Volume = 2.50 mol/L x 17.0 x 10-3 L = 0.0425 mol. Hence, the number of moles of MOH = 0.0425 mol.

The molar mass of alkali metal hydroxide (MOH) is its mass divided by the number of moles. Hence, Molar mass = mass (g) / moles = 4.36 g / 0.0425 mol = 102.59 g/mol. This molar mass is closest to the molar mass of Potassium Hydroxide (KOH), which is 39.10 (K) + 15.9994 (O) + 1.00784 (H) = 56.11 g/mol. So, the alkali metal cation in the unknown metal hydroxide is K+ (Potassium).

https://brainly.com/question/30415532

#SPJ12

The provided unknown sample contains Rubidium (Rb⁺) as its alkali metal cation. This conclusion is based on titration calculations, yielding a molar mass closest to Rb.

To identify the alkali metal cation (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺) from the given sample, we need to perform a titration calculation. Here are the steps:

First, calculate the moles of HCl used in the titration:

The balanced equation for the reaction is:

MOH + HCl → MCl + H2O

Since the reaction is 1:1, moles of MOH = moles of HCl = 0.0425 mol

Next, calculate the molar mass of the alkali metal hydroxide (MOH):

Given MOH is an alkali metal hydroxide, its molar mass is the sum of the molar masses of M, O, and H, which is represented as:

M + 17.01 (since the molar mass of OH is 17.01 g/mol)

Therefore, M = 102.59 - 17.01 ≈ 85.58 g/mol

Match this result with the molar masses of the alkali metals:

The metal with a molar mass closest to 85.58 g/mol is Rb (Rubidium).

Therefore, the alkali metal cation is Rb⁺ (Rubidium).

Answer:

233 g

Explanation:

Let's consider the following reaction.

CaCO₃ → CaO + CO₂

We can establish the following relations:

The mass of carbon dioxide produced from 530 g of calcium carbonate is:

[tex]530gCaCO_{3}\frac{1molCaCO_{3}}{100.09gCaCO_{3}} ,\frac{1molCO_{2}}{1molCaCO_{3}} .\frac{44.01gCO_{2}}{1molCO_{2}} =233gCO_{2}[/tex]

233 gram of carbon dioxide gas is produced from the decomposition of calcium carbonate.

[tex]CaCO_3\rightarrow CaO + CO_2[/tex]

From the above decomposition, we can say that the molar ratio of calcium carbonate to carbon dioxide is 1:1.

The molar mass of calcium carbonate is 100.09 g/mol.

The molar ratio of calcium carbonate to carbon dioxide is 1:1.

The molar mass of carbon dioxide is 44.01 g/mol

The mass of carbon dioxide produced from 530 g of calcium carbonate is:

[tex]{530\ gCaCO_3}\times\frac{1molCaCO_3}{100gCaCO_3} \times\frac{1molCO_2}{1molCaCO_3} \times\frac{44.01\ gCO_2}{1molCO_2} =233\ gCO_2[/tex]

So, the 233 g [tex]CO_2[/tex] will be produced.

Find more information about the decomposition and production here

brainly.com/question/883757

Answer:

The mass of glucose that contains a million [tex]1.0\times 10^6[/tex] carbon atoms is [tex]4.98\times 10^{-17} g[/tex].

Explanation:

Number of carbon atoms = [tex]1.0\times 10^6 [/tex]

1 molecule of glucose has 6 carbon atoms, then [tex]1.01\times 10^6 [/tex] will be in N molecules of glucose:

[tex]N=\frac{1.0\times 10^6}{6}[/tex]molecules of glucose

1 mole = [tex]N_A=6.022\times 10^{23} molecules[/tex]

Moles of glucose = n

[tex]N=n\times N_A[/tex]

[tex]n=\frac{N}{N_A}=\frac{\frac{1.0\times 10^6}{6}}{6.022\times 10^{23}}[/tex]

[tex]n=2.768\times 10^{-19} moles[/tex]

Mass of [tex]2.768\times 10^{-19} [/tex] moles of glucose;

[tex]2.768\times 10^{-19} mol\times 180=4.9817\times 10^{-17} g\approx 4.98\times 10^{-17} g[/tex]

Calculate the mass of glucose C₆H₁₂O₆ that contains a million (1.0 × 10⁶) carbon atoms. Be sure your answer has a unit symbol if necessary, and round it to 2 significant digits.

The mass of glucose that contains a million carbon atoms is 5.04 × 10⁻⁷ g.

1 molecule of glucose contains 6 carbon atoms. The number of molecules of glucose that contain 1.0 × 10⁶ carbon atoms are:

[tex]1.0 \times 10^{6}\ C\ atoms \times \frac{1\ Glucose\ molecule}{6\ C\ atoms} = 1.7 \times 10^{5} \ Glucose\ molecule[/tex]

We will convert molecules into moles using Avogadro's number: there are 6.02 × 10²³ molecules in 1 mole of molecules.

[tex]1.7 \times 10^{5} \ molecule \times \frac{1mol}{6.02 \times 10^{23} \ molecule} = 2.8 \times 10^{-19} \ mol[/tex]

We will convert moles to mass using the molar mass of glucose (180.16 g/mol).

[tex]2.8 \times 10^{-19} \ mol \times \frac{180.16g}{1mol} =5.04 \times 10^{-7} g[/tex]

The mass of glucose that contains a million carbon atoms is 5.04 × 10⁻⁷ g.

You can learn more about Avogadro's number here: https://brainly.com/question/13302703

Explanation:

When we move across a period from left to right then there will occur an increase in electronegativity and also there will occur an increase in non-metallic character of the elements.

As cesium (Cs) is a group 1 element and radon (Rn) is a group 18 element. Hence, cesium (Cs) is more metallic in nature than radon.

This means that radon (Rn) is less metallic than cesium (Cs).

Tin (Sn) is a group 14 element and tellurium (Te) is a group 16 element. Hence, Te is less metallic than Sn.

Selenium (Se) is a group 16 element and germanium (Ge) is a group 14 element. Therefore, selenium being more non-metallic in nature is actually less metallic than Ge.

1. The fraction of the atomic volume occupied by the nucleus is approximately 0.0000064 or 6.4 x 10^-6.

2. The density of a proton is approximately 5.77 x 10^20 g/cm^3.

Part 1: Fraction of atomic volume occupied by nucleus

**1. Calculate volumes of atom and nucleus:**

- Convert Å to m:

   - Atom diameter: 2.50 Å * 10^-10 m/Å = 2.50 x 10^-10 m

   - Nucleus diameter: 9.00 x 10^-5 Å * 10^-10 m/Å = 9.00 x 10^-15 m

- Calculate radii:

   - Atom radius: 2.50 x 10^-10 m / 2 = 1.25 x 10^-10 m

   - Nucleus radius: 9.00 x 10^-15 m / 2 = 4.50 x 10^-15 m

- Calculate volumes of spheres using the formula (4/3)πr³:

   - Atom volume: (4/3)π * (1.25 x 10^-10 m)³ ≈ 8.18 x 10^-31 m³

   - Nucleus volume: (4/3)π * (4.50 x 10^-15 m)³ ≈ 52.36 x 10^-44 m³

**2. Calculate fraction of volume occupied by nucleus:**

- Divide nucleus volume by atom volume:

   - Fraction = 52.36 x 10^-44 m³ / 8.18 x 10^-31 m³ ≈ 0.0000064

Therefore, the fraction of the atomic volume occupied by the nucleus is approximately 0.0000064 or 6.4 x 10^-6.

Part 2: Density of a proton

**1. Convert mass of proton to kg:**

- 1 amu = 1.66057 x 10^-27 kg

- Proton mass: 1.0073 amu * 1.66057 x 10^-27 kg/amu ≈ 1.6726 x 10^-27 kg

**2. Calculate volume of a proton from its diameter:**

- Proton radius: 1.72 x 10^-15 m / 2 = 8.60 x 10^-16 m

- Proton volume: (4/3)π * (8.60 x 10^-16 m)³ ≈ 2.90 x 10^-45 m³

**3. Calculate density:**

- Divide proton mass by its volume:

   - Density = 1.6726 x 10^-27 kg / 2.90 x 10^-45 m³ ≈ 5.77 x 10^17 kg/m³

**4. Convert density to g/cm^3:**

- 1 kg/m³ = 1000 g/cm³

- Density ≈ 5.77 x 10^17 kg/m³ * 1000 g/cm³ ≈ 5.77 x 10^20 g/cm³

Therefore, the density of a proton is approximately 5.77 x 10^20 g/cm^3.

The 2p sublevel has quantum numbers n=2, l=1, and possible ml values of -1, 0, +1, with a maximum of 6 electrons. The 5f sublevel has quantum numbers n=5, l=3, and possible ml values ranging from -3 to +3, holding up to 14 electrons.

The n, l, and possible ml values for 2p and 5f sublevels are derived from the quantum numbers that define the properties of electrons in atoms. For the 2p sublevel, n is 2 (the principal quantum number indicating the second shell), l is 1 (the angular momentum quantum number corresponding to a p sublevel), and the possible ml values range from -1 to +1 (which are -1, 0, and 1), making for three possible orientations.

For the 5f sublevel, n is 5 (indicating the fifth shell), l is 3 (f sublevel), and the possible ml values range from -3 to +3 (which are -3, -2, -1, 0, 1, 2, 3), resulting in a total of seven possible orientations. Using the formula maximum number of electrons that can be in a subshell = 2(2l + 1), we can calculate that the 2p sublevel can hold a maximum of 6 electrons and the 5f sublevel can hold up to 14 electrons.

Compound A is an optically active ketone, B is a chiral secondary alcohol, and C is an alkene formed from A by a Wolff-Kishner reduction. Acid D is a carboxylic acid crafted from the oxidation of alkene C.

This problem involves the identification of chemical compounds through a series of reactions and stereochemical considerations. We start by identifying compound A as an optically active ketone with the molecular formula C11H12O, since it gave a negative Tollens test. LiAlH4, a strong reducing agent, follows by acid treatment, produces compound B, an alcohol that can be resolved into enantiomers, suggesting that compound A must be a ketone, as LiAlH4 can reduce ketones to secondary alcohols, which can be chiral.

When compound B reacts with CrO3/pyridine, it reverts to the optically inactive ketone compound A. This suggests that compound B is a secondary alcohol that, when oxidized, returns to the original ketone without any chirality, indicating the presence of a stereocenter in B.

Heating compound A with hydrazine in base to give hydrocarbon C suggests a Wolff-Kishner reduction, which completely removes oxygen atoms from ketones or aldehydes to yield hydrocarbons. Finally, when compound C is oxidized with alkaline KMnO4 to give carboxylic acid D, this indicates that C is an alkene.

Compound A is Ketone, Compound B is chiral alcohol, Compound C is hydrocarbon, Compound D is carboxylic acid.

Let's break down the given information step by step:

1. Compound A, [tex]C_{11}H_{12}O[/tex], gave a negative Tollens test:

This suggests that compound A does not contain an aldehyde functional group. Instead, it may contain a ketone or another functional group that does not react with Tollens reagent.

2. Compound A was treated with [tex]LiAlH_4[/tex], followed by dilute acid, to give compound B, which could be resolved into enantiomers:

The reduction of a ketone with [tex]LiAlH_4[/tex] followed by hydrolysis with dilute acid converts the ketone to a chiral alcohol. Since compound B can be resolved into enantiomers, it suggests that compound A was a prochiral ketone.

3. When optically active B was treated with [tex]CrO_3[/tex] in pyridine, an optically inactive sample of A was obtained:

This reaction is a oxidation reaction known as the Jones oxidation. It converts a secondary alcohol (like B) into a ketone without affecting the optical activity. However, since an optically inactive sample of A was obtained, it suggests that compound B must have been racemic (an equal mixture of its enantiomers). This indicates that the chiral center in compound B was destroyed during the oxidation.

4. Heating A with hydrazine in base gave hydrocarbon C, which, when heated with alkaline KMnO4, gave carboxylic acid D:

Heating a ketone with hydrazine in base (Wolff-Kishner reduction) converts it into a hydrocarbon. This indicates that compound A was a ketone. Furthermore, oxidation of hydrocarbon C with alkaline [tex]KMnO_4[/tex]gives a carboxylic acid. This suggests that hydrocarbon C must have been a primary alcohol.

Answer:

Explanation:

Niobium has an anomalous ground-state electron configuration for a Group 5 element: [Kr] 5s¹4d⁴ . IT is anomalous because in normal course , it should have been [Kr] 5s²4d³ Or [Kr] 5s⁰4d⁵ . It is so because 5s subshell

has lesser energy than 4d subshell ,  or half filled 4d subshell is more stable. But the stable configuration is [Kr] 5s¹4d⁴ . It is so because the energy gap between 5s and 4d is very little. So one electron of 5s² gets Transferred to 4d subshell.  This paramagnetic behavior is confirmed by its dipole moment , equivalent to 5 unpaired electrons.

Answer:

1)- 0.11 m Fe(NO₃)₃  ⇒ A- Lowest freezing point

2)- 0.18 m NaOH ⇒ D- Highest freezing point

3)- 0.21 m FeSO₄ ⇒ B- Second lowest freezing point

4)- 0.38 m Glucose ⇒ C- Third lowest freezing point

Explanation:

Freezing point depression is given by the following equation:

ΔTf= Kf x m x i

As it is a depression point (final temperature is lower than initial temperature), as higher is ΔTf, lower is the freezing point. Kf is the cryoscopic constant. For water, Kf= 1.853 K·kg/mol. At high m (molality of solute) and i (Van't Hoff factor, dissociated species), the freezing point will be low.

Kf is the same for all solution, so we can simply calculate m x i and order the solutions from high m x i (lowest freezing point) to low m x i (highest freezing point):

      m x i = 0.11 x 4 = 0.44

      A) Lowest freezing point

    m x i = 0.18 x 2= 0.36

    D) Highest freezing point

    m x i = 0.21 x 1= 0.42

    B) Second lowest freezing point

    m x i = 0.38 x 1 = 0.38

    C) Third lowest freezing point

A fall in the hotness and coldness at which the matter freezes is called freezing point depression.

It can be calculated using:

[tex]\Delta \text{T}_{\text{f}} &= \text{K}_{\text{f}} \times \text{m} \times \text{ i}[/tex]

For all the solution [tex]\text{k}_{\text{f}}[/tex] value is constant hence, m × i can be calculated to know the order of lowest and highest freezing points.

The correct matches are:

1) 0.11 m Fe(NO₃)₃ ⇒ Option A. Lowest freezing point

2) 0.18 m NaOH ⇒ Option D. Highest freezing point

3) 0.21 m FeSO₄ ⇒ Option B. Second lowest freezing point

4) 0.38 m Glucose ⇒ Option C. Third lowest freezing point

To learn more about freezing point depression refer to the link:

https://brainly.com/question/25165904

Answer:

43.47 g

Explanation:

The boiling point elevation is described as:

Where ΔT is the difference in boiling points: 120.6-118.4 = 2.2 °C

K is the boiling point elevation constant, K= 2.40 °C·kg·mol⁻¹

and m is the molality of the solution (molality = mol solute/kg solvent).

So first we calculate the molality of the solution:

Now we calculate the moles of benzamide (C₇H₇NO, MW=315g/mol), using the given mass of the liquid X.

Finally we convert moles of C₇H₇NO into grams, using its molecular weight:

Final answer:

To calculate the mass of C7H7NO dissolved in the solution, use the formula for boiling point elevation in a solution.

Explanation:

The mass of C7H7NO that was dissolved in the solution can be calculated using the formula:

ΔTb = i * K * m

Where ΔTb is the boiling point elevation, i is the van't Hoff factor (number of particles the solute dissociates into), K is the boiling point elevation constant, and m is the molality of the solution.

Substitute the given values into the equation to find the mass of C7H7NO dissolved.

Answer:

P = 2.65 E-3 mm Hg

Explanation:

liquid-vapor equilibrium:

⇒ ec. Clausius-Clapeyron:

∴ R = 8.314 E-3 KJ/K.mol

∴ ΔHv = 59.11 KJ/mol

∴ T2 = 25°C ≅ 298 K

∴ T1 = 356.7°C = 629.7 K

normal boiling point:

∴ P = 1 atm = P1 = 101.325 KPa

vapor pressure (P2):

⇒ Ln P2 - Ln (101.325) = - (59.11 KJ/mol)/(8.314 E-3 KJ/K.mol)*[ (1/298) - (1/629.7) ]

⇒ Ln P2  - 4.618 = - (7109.694 K)*[ 1.7676 E-3 K-1 ]

⇒ Ln P2 = 4.618  - 12.567

⇒ P2 = e∧(-7.9494)

⇒ P2 = (3.5313 E-4 KPa)×(7.50062mm Hg/KPa) = 2.65 E-3 mm Hg

Answer:

The rate of the reaction increased by a factor of 1012.32

Explanation:

Applying Arrhenius equation

ln(k₂/k₁) = Ea/R(1/T₁ - 1/T₂)

where;

k₂/k₁ is the ratio of the rates which is the factor

Ea is the activation energy = 274 kJ/mol.

T₁ is the initial temperature = 231⁰C = 504 k

T₂ is the final temperature = 293⁰C = 566 k

R is gas constant = 8.314 J/Kmol

Substituting this values into the equation above;

ln(k₂/k₁) = 274000/8.314(1/504 - 1/566)

ln(k₂/k₁) = 32956.4589 (0.00198-0.00177)

ln(k₂/k₁)  = 6.92

k₂/k₁ = exp(6.92)

k₂/k₁ = 1012.32

The rate of the reaction increased by 1012.32

Answer:

By a factor of 2.25.

Explanation:

Using the Arrhenius equations for the given conditions:

k1 = A*(exp^(-Ea/(RT1))

k2 = A*(exp^(-Ea/(RT2))

T1 = 231°C

= 231 + 273.15 K

= 574.15 K

T2 = 293°C

= 293 + 273.15 K

= 566.15 K

Ea = 274 kJ mol^-1

R= 0.008314 kJ/mol.K

Now divide the second by the first:

k2/k1 = exp^(-Ea/R * (1/T2 - (1/T1))

= 0.444

2.25k2 = k1

Explanation:

Magnesium oxide

Amino acids are more soluble in aqueous solvent at pH extremes due to their charged nature, which increases their solubility in polar solvents. The neutral charge of an amino acid at its isoelectric point makes it hydrophobic and less soluble. At very low or very high pH, amino acids have increased charge and form more salt bonds with water, increasing their solubility.

This phenomenon can be explained by the properties of amino acids at different pH values. At the isoelectric point (pI), the amino acid is neutral, which makes it hydrophobic and less soluble in water (option A). At pH extremes, the amino acid molecules mostly carry a net charge, which increases their solubility in polar solvents (option B). In addition, at very low or very high pH, the amino acid molecules have increased charge and form more salt bonds with water solvent molecules, further enhancing their solubility (option C).

Final answer:

The accuracy of an umpire knowing the position of a baseball depends on the speed of the baseball and the percentage uncertainty in that speed. The formula Δx = v × Δt can be used to calculate the uncertainty in the position of the baseball. For example, if the umpire measures the position of the baseball over a time interval of 1 second, the uncertainty in the position would be 44.7 meters.

Explanation:

The accuracy with which an umpire can know the position of a baseball depends on several factors, including the speed of the baseball and the percentage uncertainty in that speed.

Given that the baseball is moving at 100.0 mi/h ± 1.00% (44.7 m/s ± 1.00%), and assuming the umpire can accurately measure the speed, the uncertainty in the position of the baseball can be calculated using the formula:

Δx = v × Δt

where Δx is the uncertainty in the position, v is the velocity of the baseball, and Δt is the time interval over which the position is being measured.

For example, if the umpire measures the position of the baseball over a time interval of 1 second, the uncertainty in the position would be 44.7 m/s × 1 s = 44.7 meters.

Answer:

The answers indicate that wavelength is inversely proportional to the energy of light (photon)

Explanation:

Energy of photon E = hc/λ

where;

h is Planck's constant = 6.626 X 10⁻³⁴js

c is the speed of light (photon) = 3 X 10⁸ m/s

λ is the wavelength of the photon

⇒For ultraviolet ray, with wavelength λ = 1 x 10⁻⁸ m

E = (6.626 X 10⁻³⁴ X 3 X 10⁸)/ (1 x 10⁻⁸)

E = 19.878 10⁻¹⁸ J

⇒For Visible light, with wavelength λ = 5 x 10⁻⁷ m

E = (6.626 X 10⁻³⁴ X 3 X 10⁸)/ (5 x 10⁻⁷)

E = 3.9756 X 10⁻¹⁹ J

⇒For Infrared, with wavelength λ = 1 x 10⁴ m

E = (6.626 X 10⁻³⁴ X 3 X 10⁸)/ (1 x 10⁴)

E = 19.878 X 10⁻³⁰ J

From the result above, ultraviolet ray has the shortest wavelength, but it has the highest energy among other lights.

Also infrared has the highest wavelength but the least energy among other lights.

Hence, wavelength is inversely proportional to the energy of light (photon).

The energies of one photon of ultraviolet (λ = 1 x 10⁻⁸ m), visible (λ = 5 x 10⁻⁷ m), and infrared (λ = 1 x 10⁴ m) light are [tex]1.988 \times 10^{-17} \, \text{J} \),[/tex]  [tex]3.98 \times 10^{-19} \, \text{J} \),[/tex] [tex]1.99 \times 10^{-30} \, \text{J} \)[/tex] respectively. The answers indicate that as the wavelength of light decreases, the energy of the photons increases.

To calculate the energy of a photon, we use the formula:

[tex]\[ E = \frac{hc}{\lambda} \][/tex]

where:

- E is the energy of the photon

- h  is Planck's constant [tex](\( 6.626 \times 10^{-34} \, \text{J} \cdot \text{s} \))[/tex]

- c is the speed of light in a vacuum [tex](\( 3.00 \times 10^8 \, \text{m/s} \))[/tex]

- [tex]\( \lambda \)[/tex] is the wavelength of the photon

Let's calculate the energy for each type of light:

Ultraviolet Light (λ = 1 x 10⁻⁸ m)

[tex]\[ E_\text{UV} = \frac{6.626 \times 10^{-34} \, \text{J} \cdot \text{s} \times 3.00 \times 10^8 \, \text{m/s}}{1 \times 10^{-8} \, \text{m}} \][/tex]

Visible Light (λ = 5 x 10⁻⁷ m)

[tex]\[ E_\text{Visible} = \frac{6.626 \times 10^{-34} \, \text{J} \cdot \text{s} \times 3.00 \times 10^8 \, \text{m/s}}{5 \times 10^{-7} \, \text{m}} \][/tex]

Infrared Light (λ = 1 x 10⁴ m)

[tex]\[ E_\text{IR} = \frac{6.626 \times 10^{-34} \, \text{J} \cdot \text{s} \times 3.00 \times 10^8 \, \text{m/s}}{1 \times 10^4 \, \text{m}} \][/tex]

Let's compute these values:

1. Ultraviolet Light:

[tex]\[ E_\text{UV} = \frac{6.626 \times 10^{-34} \times 3.00 \times 10^8}{1 \times 10^{-8}} \][/tex]

[tex]\[ E_\text{UV} = \frac{19.878 \times 10^{-26}}{1 \times 10^{-8}} \][/tex]

[tex]\[ E_\text{UV} = 19.878 \times 10^{-18} \][/tex]

[tex]\[ E_\text{UV} = 1.988 \times 10^{-17} \, \text{J} \][/tex]

2. Visible Light:

[tex]\[ E_\text{Visible} = \frac{6.626 \times 10^{-34} \times 3.00 \times 10^8}{5 \times 10^{-7}} \]\[ E_\text{Visible} = \frac{19.878 \times 10^{-26}}{5 \times 10^{-7}} \]\[ E_\text{Visible} = 3.9756 \times 10^{-19} \]\[ E_\text{Visible} = 3.98 \times 10^{-19} \, \text{J} \][/tex]

3. Infrared Light:

[tex]\[ E_\text{IR} = \frac{6.626 \times 10^{-34} \times 3.00 \times 10^8}{1 \times 10^4} \]\[ E_\text{IR} = \frac{19.878 \times 10^{-26}}{1 \times 10^4} \]\[ E_\text{IR} = 1.9878 \times 10^{-30} \]\[ E_\text{IR} = 1.99 \times 10^{-30} \, \text{J} \][/tex]

Summary of Energies

- Ultraviolet Light (λ = 1 x 10⁻⁸ m): [tex]\( E_\text{UV} = 1.988 \times 10^{-17} \, \text{J} \)[/tex]

- Visible Light (λ = 5 x 10⁻⁷ m): [tex]\( E_\text{Visible} = 3.98 \times 10^{-19} \, \text{J} \)[/tex]

- Infrared Light (λ = 1 x 10⁴ m): [tex]\( E_\text{IR} = 1.99 \times 10^{-30} \, \text{J} \)[/tex]

Relationship between Wavelength and Energy

Specifically:

- Ultraviolet light has the shortest wavelength and the highest energy.

- Visible light has a moderate wavelength and moderate energy.

- Infrared light has the longest wavelength and the lowest energy.

This inverse relationship between wavelength and photon energy is consistent with the equation [tex]\( E = \frac{hc}{\lambda} \)[/tex]. As [tex]\( \lambda \) (wavelength) decreases, \( E \)[/tex] (energy) increases, and vice versa.

Answer:

Molality for the solution is 2.22 m

Explanation:

Molality is a sort of concentration. Indicated the moles of solute in 1kg of solvent. → mol/kg

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

17.85 g / 92 g/mol = 0.194 moles

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

87.4 g . 1kg / 1000 g = 0.0874 kg

Mol/kg → Molality

0.194 mol / 0.0874 kg = 2.22 m

Answer:

volume of gas = 9.1436cm³

Explanation:

We will only temperature from °C to K since the conversion is done by the addition of 273 to the Celsius value.

Its not necessary to convert pressure and volume as their conversions are done by multiplication and upon division using the combined gas equation, the factors used in their conversions will cancel out.

V1 =10.1cm³ , P1 =746mmHg,     T1=23°C =23+273=296k

V2 =? ,   P2 =760mmmHg ,     T2=0°C = 0+273 =273K

Using the combined gas equation to calculate for V2;

[tex]\frac{V1P1}{T1}=\frac{V2P2}{T2} \\ re-arranging, \\V2 =\frac{V1P1T2}{P2T1}[/tex]

[tex]V2 =\frac{10.1*746*273}{760*296}[/tex]

V2=9.1436cm³

Answer : The  mass of [tex]KC_2H_5CO_2[/tex] is, 24.5 grams

Explanation : Given,

[tex]K_a=1.3\times 10^{-5}[/tex]

pH = 5.02

Concentration of [tex]HC_2H_5CO_2[/tex] = 1.30 M

Volume of solution = 125 mL = 0.125 L

First we have to calculate the value of [tex]pK_a[/tex].

The expression used for the calculation of [tex]pK_a[/tex] is,

[tex]pK_a=-\log (K_a)[/tex]

Now put the value of [tex]K_a[/tex] in this expression, we get:

[tex]pK_a=-\log (1.3\times 10^{-5})[/tex]

[tex]pK_a=5-\log (1.3)[/tex]

[tex]pK_a=4.89[/tex]

Now we have to calculate the concentration of [tex]KC_2H_5CO_2[/tex]

Using Henderson Hesselbach equation :

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

[tex]pH=pK_a+\log \frac{[KC_2H_5CO_2]}{[HC_2H_5CO_2]}[/tex]

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

[tex]5.02=4.89+\log (\frac{[KC_2H_5CO_2]}{1.30})[/tex]

[tex][KC_2H_5CO_2]=1.75M[/tex]

Now we have to calculate the moles of [tex]KC_2H_5CO_2[/tex]

[tex]\text{Moles of }KC_2H_5CO_2=1.75M\times 0.125L=0.219mol[/tex]

Now we have to calculate the mass of [tex]KC_2H_5CO_2[/tex]

[tex]\text{Mass of }KC_2H_5CO_2=\text{Moles of }KC_2H_5CO_2\times \text{Molar mass of }KC_2H_5CO_2[/tex]

Molar mass of [tex]KC_2H_5CO_2[/tex] = 112 g/mol

[tex]\text{Mass of }KC_2H_5CO_2=0.219mol\times 112g/mol=24.5g[/tex]

Thus, the mass of [tex]KC_2H_5CO_2[/tex] is, 24.5 grams

To find the mass of KC₂H₃CO₂ needed to create a buffer at pH 5.02, the Henderson-Hasselbalch equation is used to calculate the ratio of conjugate base to acid, then the molar mass is used to convert moles to mass, the concentration of A⁻ is approximately 1.755 M.

The question asks for the mass of potassium propanoate (KC₂H₃CO₂) needed to create a buffer with a specific pH from a solution of propanoic acid (KC₂H₃CO₂). To solve this, we apply the Henderson-Hasselbalch equation:

[tex]\[ pH = pKa + \log \left( \frac{[A^-]}{[HA]} \right) \][/tex]

Given variables:

Rearranging the equation to solve for A⁻:

A⁻ = [tex][HA] \times 10^{(pH - pKa)}[/tex]

A⁻ = 1.755M

After calculating A⁻, it's then converted from molarity to moles given the volume of the solution. Finally, the mass of KC₂H₃CO₂ is 1.755M by multiplying the number of moles of A⁻ by its molar mass.

Glycine, an amino acid, changes its structure and net charge in response to pH due to two dissociable protons. At pH 2 it's fully protonated with a net charge of +1. At pH 7, its carboxyl group loses a proton leaving the net charge to 0. By pH 10, both the carboxyl and amino group have lost protons, so the net charge is -1.

The amino acid glycine (H2N–CH2–COOH) has two dissociable protons, one associated with its carboxyl group (pK 2.35) and one with its amino group (pK 9.78). At very low pH values, protons are abundant, meaning glycine is in its fully protonated form with a net charge of +1. Thus, at pH 2, the structure is H3N+–CH2–COOH and the net charge is +1.

At pH 7, the proton on the carboxyl group is lost, leaving the carboxylate form (COO-) and the proceed ammonium group (NH3+). Our structure therefore becomes H3N+–CH2–COO- with a net charge of zero.

Finally, at pH 10, glycine loses both of its protons. The structure now is H2N–CH2–COO- and the net charge is -1.

https://brainly.com/question/33407334

#SPJ6

Answer:

The question is incomplete as some details are missing. Here is the complete question ; When I was a boy, Uncle Wilbur let me watch as he analyzed the iron content of runoff from his banana ranch. A 25.0-mL sample was acidified with nitric acid and treated with excess KSCN to form a red complex. (KSCN itself is colorless.) The solution was then diluted to 100.0 mL and put in a variable-pathlength cell. For comparison, a 10.0-mL reference sample of 6.80 104 M Fe3 was treated with HNO3 and KSCN and diluted to 50.0 mL. The reference was placed in a cell with a 1.00-cm light path. The runoff sample exhibited the same absorbance as the reference when the pathlength of the runoff cell was 2.48 cm. What was the concentration of iron in Uncle Wilbur

Explanation:

The concept of beer Lambert Law and the dilution formula was used in solving the question. According to Beer Lambert law, as light enters through a solution that has an intensity Io, and emerges with intensity I with an assumed concentration c in mol/dm3 at a length l cm.

Mathematically from beer lambert law ; ecl =Ig (Io/I), where e is the extinction coefficient.

The attached file shows the detailed steps and appropriate substitution.