Three of the reactions that occur when the paraffin of a candle (typical formula C21H44) burns are as follows:

(1) Complete combustion forms CO2 and water vapor.
(2) Incomplete combustion forms CO and water vapor.
(3) Some wax is oxidized to elemental C (soot) and water vapor.


(a) Find ΔH∘rxn of each reaction (ΔH∘f of C21H44=−476kJ/mol; use graphite for elemental carbon).

(b) Find q (in kJ) when a 254-g candle bums completely.

(c) Find q (in kJ) when 8.00% by mass of the candle burns incompletely and another 5.00% undergoes soot formation.

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 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:

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.

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

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 condensed ground-state electron configuration for each is:

(a) [tex][Ar]4s^24p^{1}[/tex]

(b) [tex][Ar]4s^23d^{10}[/tex]

(c) [tex][Ar]4s^23d^{1}[/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, Ga (Gallium)

As we know that the gallium element belongs to group 13 and the atomic number is, 31

The ground-state electron configuration of Ga is:

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

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

[tex][Ar]4s^24p^{1}[/tex]

(b) The given element is, Zn (Zinc)

As we know that the zinc element belongs to group 12 and the atomic number is, 30

The ground-state electron configuration of Zn is:

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

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

[tex][Ar]4s^23d^{10}[/tex]

(c) The given element is, Sc (Scandium)

As we know that the scandium element belongs to group 3 and the atomic number is, 21

The ground-state electron configuration of Sc is:

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

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

[tex][Ar]4s^23d^{1}[/tex]

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.

The given question is incomplete. The complete question is as follows.

A 0.6-m3 rigid tank is filled with saturated liquid water at 135°C. A valve at the bottom of the tank is now opened, and one-half of the total mass is withdrawn from the tank in liquid form. Heat is transferred to water from a source of 210°C so that the temperature in the tank remains constant. Assume the surroundings to be at 25°C and 100 kPa. Determine the amount of heat transfer.

Explanation:

First, we will determine the initial mass from given volume and specific volume as follows.

              [tex]m_{1} = \frac{V}{\alpha_{1}}[/tex]

                         = [tex]\frac{0.6}{0.001075}kg[/tex]

                         = 558.14 kg

Hence, the final mass and mass that has left the tank are as follows.

             [tex]m_{2} = m_{out} = \frac{1}{2}m_{1}[/tex]  

                          = [tex]\frac{1}{2} \times 558.14 kg[/tex]

                          = 279.07 kg

Now, the final specific volume is as follows.

          [tex]\alpha_{2} = \frac{V}{m_{2}}[/tex]

                        = [tex]\frac{0.6}{279.07} m^{3}/kg[/tex]

                        = 0.00215 [tex]m^{3}/kg[/tex]

Final quality of the mixture is determined actually from the total final specific volume and the specific volumes of the constituents for the given temperature are as follows.

           [tex]q_{2} = \frac{\alpha_{2} - \alpha_{liq135}}{(\alpha_{vap} - \alpha_{liq})_{135}}[/tex]

                        = [tex]\frac{0.00215 - 0.001075}{0.58179 - 0.001075}[/tex]

                        = [tex]1.85 \times 10^{-3}[/tex]

Hence, the final internal energy will be calculated as follows.

          [tex]u_{2} = u_{liq135} + q_{2}u_{vap135}[/tex]

                      = [tex](567.41 + 1.85 \times 10^{-3} \times 1977.3) kJ/kg[/tex]

                      = 571.06 kJ/kg

Now, we will calculate the heat transfer as follows.

            [tex]\Delta U = Q - m_{out}h_{out}[/tex]

      [tex]m_{2}u_{2} - m_{1}u_{1} = Q - m_{out}h_{out}[/tex]

                Q = [tex](279.07 \times 571.06 - 558.14 \times 567.41 + 279.07 \times 567.75) kJ[/tex]

                    = 1113.5 kJ

Thus, we can conclude that amount of heat transfer is 1113.5 kJ.

Final answer:

The question involves concepts of thermodynamics, specifically related to heat transfer and thermal equilibrium in a situation with a saturated liquid undergoing withdrawal and heating to maintain a constant temperature, demonstrating the application of energy conservation principles.

Explanation:

The question describes a thermodynamics scenario where heat transfer is involved to maintain the temperature of the system (a tank with water) constant. The water inside the rigid tank undergoes a process where half of its mass is withdrawn while the temperature is kept at 135°C through the addition of heat from a 210°C source. This is an example of applying the concepts of thermodynamics such as energy transfer, the properties of substances under varying conditions, and the concept of a saturated liquid.

When dealing with the thermal equilibrium between two bodies with different initial temperatures, the overall heat lost by the hotter body (pan) is equal to the heat gained by the colder body (water). The final temperature at equilibrium can be calculated using the principle of conservation of energy. Similarly, the expansion of a fluid within a radiator and thermal contraction of coffee in a glass can be described using thermodynamic principles and the relevant coefficients of thermal expansion and specific heat capacities.

Answer: The enthalpy change is 34.3 kJ

Explanation:

The conversions involved in this process are :

[tex](1):H_2O(s)(-18^0C)\rightarrow H_2O(s)(0^0C)\\\\(2):H_2O(s)(0^0C)\rightarrow H_2O(l)(0^0C)\\\\(3):H_2O(l)(0^0C)\rightarrow H_2O(l)(25^0C)[/tex]

Now we have to calculate the enthalpy change.

[tex]\Delta H=[m\times c_{s}\times (T_{final}-T_{initial})]+n\times \Delta H_{fusion}+[m\times c_{l}\times (T_{final}-T_{initial})][/tex]

where,

[tex]\Delta H[/tex] = enthalpy change = ?

m = mass of water = 72.0  g

[tex]c_{s}[/tex] = specific heat of ice = [tex]2.09J/g^0C[/tex]

[tex]c_{l}[/tex] = specific heat of liquid water = [tex]4.184J/g^0C[/tex]

n = number of moles of water = [tex]\frac{\text{Mass of water}}{\text{Molar mass of water}}=\frac{72.0g}{18g/mole}=4.00moles[/tex]

[tex]\Delta H_{fusion}[/tex] = enthalpy change for fusion = 6010 J/mole

Now put all the given values in the above expression, we get

[tex]\Delta H=[72.0g\times 2.09J/g^0C\times (0-(-18)^0C]+4.00mole\times 6010J/mole+[72.0g\times 4.184J/g^)C\times (25-0)^0C][/tex][tex]\Delta H=34279.8J=34.3kJ[/tex]        (1 KJ = 1000 J)

Therefore, the enthalpy change is 34.3 kJ

Final answer:

The total amount of heat energy required to convert 72.0 g of ice at − 18.0 °C to water at 25.0 °C is 34.2 kJ. This includes heating the ice to 0 °C, melting it, and then heating the water to 25.0 °C.

Explanation:

To calculate the amount of heat energy required in kilojoules to convert 72.0 g of ice at − 18.0 °C to water at 25.0 °C, we must consider three stages of the process: heating the ice to 0 °C, melting the ice, and then heating the resulting water to 25.0 °C.

The total energy Qtotal is the sum of Q1, Q2, and Q3, which is 2664 J + 23976 J + 7566 J = 34206 J.

To convert this value to kilojoules, we divide by 1,000: 34206 J / 1000 = 34.206 kJ. Therefore, the answer to three significant figures is 34.2 kJ.

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.

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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).

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:

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.

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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

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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:

Yes, the 150-mL Erlenmeyer will be large enough to contain the acid.

Explanation:

As an instructor is preparing for an experiment, he requires 225 g phosphoric acid. Considering that the density of the phosphoric acid is 1.83 g/mL, we can find the volume occupied by the acid using the following expression.

density = mass / volume

volume = mass / density

volume = 225 g / (1.83 g/mL)

volume = 123 mL

The phosphoric acid occupies 123 mL so the 150-mL Erlenmeyer will be large enough to contain it.

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.

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:

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:

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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

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:

For a: The number of inner electrons, outer electrons and valence electrons are 28, 7 and 7 respectively.

For b: The number of inner electrons, outer electrons and valence electrons are 54, 1 and 1 respectively.

For c: The number of inner electrons, outer electrons and valence electrons are 23, 1 and 1 respectively.

For d: The number of inner electrons, outer electrons and valence electrons are 36, 2 and 2 respectively.

For e: The number of inner electrons, outer electrons and valence electrons are 2, 7 and 7 respectively.

Explanation:

Outer shell electrons are the electrons which are not tightly held by the electrons. They are called as valence electrons. The electrons present in the highest principle quantum number are known as valence electrons.

Inner shell electrons are the electrons which are tightly held by the electrons. They are called as core electrons.

Inner electrons = Total number of electrons - Valence electrons

Total number of electrons in an atom is equal to the atomic number of the element.

For the given options:

Bromine is the 35th element of the periodic table having electronic configuration of [tex]1s^22s^22p^63s^23p^64s^23d^{10}4p^5[/tex]

Highest principle quantum number is 4

Number of valence electrons = 7

Number of outer electrons = 7

Number of inner electrons = 35 - 7 = 28

Cesium is the 55th element of the periodic table having electronic configuration of [tex]1s^22s^22p^63s^23p^64s^23d^{10}4p^65s^24d^{10}5p^66s^1[/tex]

Highest principle quantum number is 6

Number of valence electrons = 1

Number of outer electrons = 1

Number of inner electrons = 55 - 1 = 54

Chromium is the 24th element of the periodic table having electronic configuration of [tex]1s^22s^22p^63s^23p^64s^13d^{5}[/tex]

Highest principle quantum number is 4

Number of valence electrons = 1

Number of outer electrons = 1

Number of inner electrons = 24 - 1 = 23

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]

Highest principle quantum number is 5

Number of valence electrons = 2

Number of outer electrons = 2

Number of inner electrons = 38 - 2 = 36

Fluorine is the 9th element of the periodic table having electronic configuration of [tex]1s^22s^22p^5[/tex]

Highest principle quantum number is 2

Number of valence electrons = 7

Number of outer electrons = 7

Number of inner electrons = 9 - 7 = 2

The number of inner, outer, and valence electrons for each element is as follows: Br has 2 inner electrons, 28 outer electrons, and 7 valence electrons; Cs has 2 inner electrons, 118 outer electrons, and 1 valence electron; Cr has 2 inner electrons, 24 outer electrons, and 6 valence electrons; Sr has 2 inner electrons, 36 outer electrons, and 2 valence electrons; F has 2 inner electrons, 7 outer electrons, and 7 valence electrons.

(a) Br has 2 inner electrons, 28 outer electrons, and 7 valence electrons.

(b) Cs has 2 inner electrons, 118 outer electrons, and 1 valence electron.

(c) Cr has 2 inner electrons, 24 outer electrons, and 6 valence electrons.

(d) Sr has 2 inner electrons, 36 outer electrons, and 2 valence electrons.

(e) F has 2 inner electrons, 7 outer electrons, and 7 valence electrons.

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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.

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:

Answer in explanation

Explanation:

Argon has 18 electrons. So to get the element in question, we only need to add 18 to the number of the filled electrons.

a. Germanium, atomic number 32

Other group members:

Silicon Si , Carbon C , Tin Sn , Lead Pb and Flerovium Fl

b. Cobalt , atomic number 27

Other group members:

Rhodium Rh , Iridium Ir and Meitnerium Mt

c. Technetium , atomic number 43

Krypton is element 36

Other group members are :

Manganese Mn , Rhenium Re and Bohrium Bh

Answer:

less than

Explanation:

The absorbance of a solution is a function of the concentration (amount) of a substance in the solution. Mathematically, if the concentration is increased, the absorbance of the solution will also increase and if the concentration is decreased, the absorbance will decrease. There will be a decrease in the value of the absorbance because the calculated and predicted masses are not the same.

Final answer:

The absorbance of a solution made from a solid may be greater or less than that of an unknown solution, depending on their respective concentrations and properties.

Explanation:

When comparing the absorbance of a solution made from a solid to that of an unknown solution, we need to consider the concentration or the size of the container. A solution made from a solid may have a higher absorbance because it contains a higher concentration of molecules that can interact with light. On the other hand, the absorbance of the unknown solution will depend on its specific properties. Therefore, whether the absorbance of the solution made from a solid is greater, less than, or the same as the absorbance of the unknown solution cannot be determined without further information.

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.

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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.

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.

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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.