What amount of energy is required to change
20.0 g of an unknown substance from -15.0 °C
to 7.0 °C? (More information on the picture!!)

Sodium and chlorine have the same shielding effect because they have the same number of innermost electrons that shield their valence electrons.

The shielding effect of an element is the electron shielding effect that valence electrons experience from the attraction of the positively-charged nucleus as a result of the inner electrons in the element.

The completely filled electron shells in the interior of an atom of an element shield or protect the electron found in the valence shell or outermost shell.

Considering why sodium and chlorine have the same shielding effect:

The electronic configuration of sodium and chlorine are 2, 8, 1 and 2,8, 7 respectively.

They both have 10 innermost electrons that shield their valence electrons.

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The options which are not true of standard cell potentials are the anode are option B, C, and D.

The standard cell potential refers to the potential difference between the cathode and anode and measures the potential of equilibrium. The standard potentials are all measured at 298 K, 1 atm, and with 1 M solutions. In a galvanic cell, current is generated when electrons flow externally through the circuit from the anode to the cathode due to a difference in potential energy between the two electrodes in the electrochemical cell. A galvanic cell generates electric current spontaneously if its cell potential is positive. Standard cell potential is determined calculated as the standard reduction potential of the cathode minus the standard reduction potential of the anode. The cathode is always the species with the greater standard reduction potential, while the anode is the species with the lower standard reduction potential. The reduction potentials are not scaled by the stoichiometric coefficients when calculating the standard cell potential.

Note: The question is incomplete. The complete question probably is: Identify the options below that are not true of standard cell potentials Select all that apply: A) A galvanic cell generates electric current spontaneously only if the cell potential is positive. B) The anode is the species with the greater standard reduction potential. C) Standard cell potential is dependent on the stoichiometry of the overall reaction. D) A galvanic cell generates electric current spontaneously only if the cell potential is negative.

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The Kp of the reaction is  7.8 * 10^4.

We know that the equilibrium constant of the reaction has to do with the manner in which the reactant can nbe able to be converted into products. In this case, we are looking at the reaction in which we are having the production of the ICl molecule.

Let us recall that;

∆G = -RTlnK

∆G = change in free energy

R = gas constant

T = absolute temperature

K = equilibrium constant.

When we substitute the values, we would now have;

lnKp =∆G/-RT

lnKp = -27.9 * 10^3/-(298 * 8.314)

lnKp = 11.3

Kp = 7.8 * 10^4

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The carboxylic acid are the functional groups generally causes a compound to have the HIGHEST boiling point, assuming the molecular weight is constant.

Carboxylic acids have better boiling factors than aldehydes, ketones or even alcohols of similar molecular mass. It is because of their. More large affiliation of carboxylic acid thru van der Waals pressure of attraction.

Carboxylic acids have better boiling factor than carbonyl compounds and alcohols because of the presence of intramolecular hydrogen bonding. Since carboxylic acids can shape a couple of set of hydrogen bonds, their boiling factors are typically better than the ones of different molecules of the identical molecular weight (MW). This could bring about a better temperature at which boiling could occur. We can see that the most important carboxylic acid from our solution alternatives is pentanoic acid.

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Gluconeogenesis and glycolysis are mutually regulated. *AMP: Glycolysis is encouraged because cells need ATP. Citrate and acetyl-CoA reporting on the citric acid cycle. Because the cell is creating energy and intermediates for biosynthetic processes when [C] is high, gluconeogenesis is encouraged.

Any atoms joined by chemical bonds are referred to be molecules in general. A molecule consisting of atoms from several elements is referred to as a compound. Molecules make up all chemicals.

The vast array of molecules that make up the human body are all combinations of just a few dozen basic constituents: the periodic table's chemical elements. But each atom's abundance is very different from the others.

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Answer:

Explanation: Molar mass of ethanol = 46g/mole.

Moles of ethanol= 3.25 moles

Molality = moles of ethanol/ Mass of solvent in kg

Mass in kg = 828/1000kg=0.828

Molality= 3.25×0.828 Mol per kg

Molality=3.92 Mole/kg

m= mass of ethanol

moles= mass/molar mass

mass= moles ×molar mass

mass= 3.25×46= 149.5 gram

The differences in the distribution of solar energy on Earth's surface is due to Earth’s curved shape and tilt on its axis do not allow the sun’s rays to fall evenly on its surface.

The correct option is D.

Solar energy refers to the energy produced by the Sun.

Solar energy is in the form of heat energy, light energy, and ultraviolet radiation.

The shape of the affects the amount of solar energy that reaches any region of the earth. The earth is spherical in shape. Hence, there is an uneven distribution of solar energy from the sun o the Earth. also, the tilt of the earth affects the amount of solar energy that reaches any region of the earth.

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Answer:

0.132 pm

Explanation:

De Broglie Wavelength is

[tex]{\displaystyle ~\lambda ={\frac {h}{mv}}.}[/tex]

or

wavelength = h / (m * v)

To calculate the De Broglie wavelength of a neutron traveling at 1% the speed of light, you will need to know the mass of the neutron and the speed of light. The mass of a neutron is about 1.675 x 10^-27 kilograms, and the speed of light is about 3.00*10^8 meters per second.

Plugging in these values, you get:

wavelength = 6.626 x 10^-34 J * s / (1.675 x 10^-27 kg * (0.01 * 3.00x10^8 m/s))

Simplifying this equation, you get:

wavelength = 1.3186x10^-13 meters

(1.3186x10^-13 meters) * (1 picometer / 10^-12 meter) =

0.132 picometers

Dalton’s atomic theory is the oldest theory about the atom. In 1808, John Dalton published his theory, which was composed of several postulates that were built based on his experiments and laws of chemical combination. A number of scientists later contributed to the development of modern atomic theory, which is different from Dalton’s atomic theory and has more advanced facts about the atom and its behavior. The key difference between Dalton’s Atomic Theory and Modern Atomic Theory is that the structure and properties of atom according to Dalton’s theory are different from the structure and properties proposed by the modern atomic theory.

Dalton’s atomic theory is a theory about indivisible particles called atoms which are the smallest particles of all matter. Modern atomic theory is the theory that explains the fully detailed structure of an atom.

According to Dalton’s atomic theory, atoms are indivisible particles. Modern atomic theory says that atoms are composed of subatomic particles; protons, electrons, and neutrons.

Dalton’s theory does not explain details about isotopes. It states that all atoms of the same element are identical. Modern atomic theory explains details about isotopes having a different number of neutrons and the same number of protons.

Dalton couldn’t give details about electrons. Modern atomic theory explains the location, reactions, and behavior of electrons.

Dalton’s atomic theory explains that atoms are the smallest particle that can be engaged in reactions. Modern atomic theory states that subatomic particles can participate in reactions.

The balanced reaction with correct coefficients for the given chemical reaction is given as,

4Sb + 3O₂ → Sb₄O₆

H₂S + Cl₂ → S + 2HCl

Balanced chemical equations are defined as the equations that have the same number and type of each atom on both sides of the equation. The coefficients in a balanced equation must be in the simplest whole number ratio. In a balanced chemical equation mass is always conserved.

The equation Sb + O₂ → Sb₄O₆ is written after balancing as 4Sb + 3O₂ → Sb₄O₆. Therefore, its coefficients are 4 and 3.

The equation H₂S + Cl₂ → S + HCl is written after balancing as H₂S + Cl₂ → S + 2HCl. Therefore, its coefficient is 2.

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Answer:

True

Explanation:

The first reaction in the Citric Acid cycle is the reaction between acetyl-CoA and oxaloacetate to form citrate. This reaction is irreversible, which means that once acetyl-CoA enters the cycle, it must complete the cycle. This step is irreversible because it is highly exergonic.

Answer:

Calcium and magnesium do not combine or react with each other to form a compound. They are both alkaline earth metals, but they do not react with each other under normal conditions. It is possible to create a compound by combining them with other elements, but the specific compound would depend on the elements used. For example, calcium and magnesium can be combined with chlorine to form calcium chloride and magnesium chloride.

The bond dissociation energy of 543 kJ/mol for a N-H bond in NH3. Hence, the answer is A. 543 kJ.

The bond dissociation energy for a N-H bond in NH3 can be calculated using the information from the following reaction and the data provided. The equation for the reaction is:

NH3 → H2 + N.

The bond dissociation energy for a N-H bond in NH3 can be calculated by subtracting the sum of the bond energies of the C-H and C-C bonds in NH3 from the sum of the bond energies of the O-H and C=O bonds in H2 and N.

The bond energies of the C-H and C-C bonds in NH3 are 414 kJ/mol and 347 kJ/mol, respectively. The bond energies of the O-H and C=O bonds in H2 and N are 464 kJ/mol and 736 kJ/mol, respectively.

Therefore, the bond dissociation energy for a N-H bond in NH3 can be calculated by subtracting the sum of 414 kJ/mol and 347 kJ/mol from the sum of 464 kJ/mol and 736 kJ/mol.

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The balanced form of the chemical equations given in the image are as follows:

A balanced chemical equation is an equation that obeys the law of conservation of mass i.e. the number of atoms of each element on both sides of the equation are the same.

A chemical equation is balanced with the aid of coefficients, which are numbers placed in front of each compound or element as a multiplying factor.

According to this question, some chemical equations were given in the image attached. The balanced form of these equations are in the main answer part.

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B) Al because the large difference between the third and forth ionization energies.

What is ionization energy?

Ionization energy (also called ionization potential) is the amount of energy required to remove an electron from an isolated atom or molecule in chemistry and physics. There is an ionization energy for each successively removed electron. However, the ionization energy associated with the removal of the first (most loosely held) electron is most commonly used.

The ionization energy of a chemical element, expressed in joules or electron volts, is usually measured in a discharge tube in which rapidly moving electrons produced by an electric current collide with gas atoms of the element, releasing one of them will be electronic.

B) Al because the large difference between the third and forth ionization energies.

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True. The product that results from the reacting bromine is the dominating one when NBS and light are used to study allylic halogenation processes of alkenes.

A carboxyl group is referred to as allylic and vinylic carbon if it is indirectly or directly attached with a double bonds in a structure. Vinylic charcoal comprises one of the atomic nuclei that create (or share) double bond, which is the primary differential among allylic versus vinylic carbon.

A chemical process known as an allylic reorganization or allylic shift occurs if the double binding in an allyl pharmaceutical molecule moves to the following carbon atom. In nucleophilic attack, it occurs.

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In the given electronic configuration, the 4 s subshell has 3 electrons which is not possible as the s subshell  can accomodate  a maximum of only two electrons.

Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.

Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.

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The reactive metals will quickly react with all three of the salt, oxygen, and strong bases. Therefore, option D is correct.

Metal can be described as a material that, when freshly prepared, and polished shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically ductile and malleable. These properties are the result of the metallic bond between the molecules of the metal.

Metal can be a chemical element such as iron and an alloy such as stainless steel, and a molecular compound such as polymeric sulfur nitride.

Metals are inclined to create cations through electron loss. Most will react with oxygen in the air to produce oxides. Some others, such as platinum, palladium, and gold, do not react with the atmosphere.

The oxides of metals are basic, as opposed to those of nonmetals are acidic or neutral. Therefore, reactive metals react with oxygen and strong bases.

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1. The water potential of the solution would be - 9.68 bars.

2. The net flow of water would be from the root into the solution.

The water potential of a solution is the tendency of water molecules to move from one solution into another solution when the two are separated by a selectively permeable membrane.

The solute potential of the solution can be calculated as:

solute potential = -iCRT. Where i is the van 't Hoff index, C is the molarity, R is the ideal gas constant, and T is the temperature in Kelvin.

For the solution, C = 0.4 M, T = 22 + 273 = 295 K

Solute potential = 1 x 0.4 x 0.082 x 295

                           = - 9.68 bars

Since the pressure potential of the solution is zero (no physical pressure is applied to the solution), the solute potential is the same as the water potential of the solution.

Now, the solution has a water potential of -9.68 bars while the root has a water potential of -5.4 bars. This means that the root has more water potential than the solution. Thus, water molecules will move from the root into the solution.

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The electronic configuration of nickel is [Ar] 3d⁸ 4s².

What is electronic configuration?

The arrangement of electrons within an atom's orbitals is known as its electronic configuration. The atomic number, which is equal to the number of protons in every neutral atom, is the set quantity of electrons that make up each neutral atom.

What is Nickel ?

A hard silver-white metallic element that can be hammered into shape, polished to a high sheen, is resistant to wearing away, and is mostly utilized in alloys.

Therefore, the electronic configuration of nickel is [Ar] 3d⁸ 4s².

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Answer: False

Explanation: Certain types of rocks are light and gravity can hold them down,

For example: A pencil is on the desk due to the gravity pulling it down.

      =)

The chemical equation of the dissociation of 0.036M HNO₂ solution is given below:

A chemical equation is an equation that uses the formula of compounds to show the reaction between substances to form products.

In a chemical equation, the reactants are written on the left-hand side of the equation, while the products are written on the right-hand side of the reaction.

Chemical equations are balanced by adding numerical coefficients in front of the compounds.

An example of a chemical equation is the equation of the dissociation of the acid nitrous acid, HNO₂.

The acid, nitrous acid, HNO₂ is a weak acid that dissociates partially to produce hydrogen ions.

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Answer:

IT IS A CHEMICAL CHANGE

Explanation:

The Old Nassau reaction or Halloween reaction is a chemical clock reaction in which a clear solution turns orange and then black

Answer:

It's a chemical change.

Aloud is trying to find evidence that a galaxy has supermassive black hole at its center. He should look for the black matter in the center of the Earth. Thus, the correct option is D.

Black matter or dark matter is composed of the particles which do not absorb, reflect, or emit light rays, so they cannot be detected by observing electromagnetic radiations. Dark matter is the material which cannot be seen directly through the eyes.

Dark matter play an important role in the formation of galaxies. Many researchers use the astronomical surveys to build maps of the location where dark matter in the universe is found based on how the light from the distant galaxies bends as it travels to us.

Thus, the matter which fall into a black hole arranges itself in the shape of a disk which is thick at the outer edge, while it is thin along the inner ring of the disk.

Therefore, the correct option is D.

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Delta H  for the reaction: C2H4 (g) + H2 (g) --> C2H6 (g) is -137kJ

What does Hess's law indicate about a reaction's enthalpy?

According to Hess's law, all intermediate reactions that can be separated into the main reaction have standard enthalpies that add up to the same value when the main reaction is carried out at the same temperature.

If the initial and ending circumstances are the same, the enthalpy change for a reaction is independent of the number of ways a product might be produced. An exothermic process is indicated by a reaction's negative enthalpy change, whereas an endothermic process is shown by a reaction's positive enthalpy change.

C2H4 (g) + 3 O2 (g) --> 2 CO2 (g) + 2 H2O (l)  Delta H = -1411. kJ

2 CO2 (g) + 3 H2O (l) --> C2H6 (g) + 3½ O2 (g)  Delta H = +1560. kJ

H2 (g) + ½O2 (g) --> H2O (l)  Delta H = -285.8 kJ

C2H4 (g) + H2 (g) --> C2H6 (g)  Delta H = -137. kJ

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The degree of unsaturation, C-H/2+1. and where C = no. of carbon, H = no. of hydrogen Molecular formula: C7H14O2, 7-14/2+1 = 1. Therefore structure will have one double bond or ring

IR analysis

the band at around 1700 cm-1 is due to the carbonyl group

the band at around 2850 - 2950 cm-1 is due to aliphatic CH stretching

(image) - LINK ATTACHED

1H NMR analysis

the triplet at 4.5 ppm is due to methylene proton attached to an oxygen

the singlet at 2.1 ppm is due to methyl proton attached to the carbonyl group

the quartet at around 1.55 ppm is due to methylene proton attached to another methylene group

the multiplet at 1.5 ppm is due to CH proton attached to two methyl group and one methylene group

the doublet at around 0.9 ppm is due to two methyl proton attached to CH

based on the above analysis the structure of the compound is - image

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statement correctly describes the electronic charge distribution in a molecule-Option 2 The electronic charge is distributed equally around each atom in the molecule.

When charged matter is positioned in an electromagnetic field, it encounters a force due to its physical property of electrical charges. A positive or negative electric charge can exist (commonly carried by protons and electrons respectively). Like charges repel each other and, while unlike goods become more expensive one another. Coulomb, unit of electrical charges in the m long system, which serves as the foundation for the SI physical unit. C is the abbreviation. The coulomb is defined as the amount of electricity transferred in one second by a one-ampere current. Charge (exhibited by protons) and negative charge are indeed the two types of charge (exhibited by electrons.

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A 35.20g sample of liquid antimony at 747.0 celcius. The heat released in the process in KJ is 11.        
                             
The given sample of liquid antimony is cooled from 747.0°C to 28.0°C
Since the melting point of antimony is 631.0°C, the liquid is cooled from 747.0°C to 631.0°C, then the phase of antimony is changed from liquid to solid at 631.0°C, and temperature of solid is changed from 63 1.0C to 631 .0°C

Specific heat of solid and liquid antimony is 0.2090J/g^0C and    

and enthalpy of fusion at 631.0°C is 161.1 J/g.

Calculate the heat released in the overall procedure as follows:

Q=q^747.0° C to 631.0°C +Q solidifying at 631.0° C q631.0° C to 28.0°C

=mCΔT+(-mΔH^solidifying )+mcΔT

-35.20 gx0.2590 J/g°631.0°C-747.0°C)+(35.20 gx161.1 J/g)

=+35.20 g× 0.2090J/g^o C × (28.0°C-631.0°C)

=--1057.55 J -5670.72 J-4436.15 J

=11164.42 J

11.164 j                

Hence, the heat released in the process in kJ is 11

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The balanced net ionic equation for the reaction that occurs when aqueous solutions of lead(II) nitrate and barium bromide is,

    Pb2+ (aq.)  + 2Br-(aq.) -------------> PbBr2

Lead(II) nitrate, Pb(NO3)2 and barium bromide, BaBr2, are soluble in aqueous solution. This which means that they dissociate completely to form cations and anions when dissolved in water.

Pb(NO2)3 (aq.) + BaBr2(aq.) -----------> PbBr2 (s) + Ba(NO3)2 (aq.)

Balanced net ionic equation for the reaction is the chemical equation that shows only those elements, compounds, and ions that are directly involved in the chemical reaction. Net ionic equations must be balanced by both mass and charge. Balancing by mass means ensuring that there are equal masses of each element on the product and reactant sides. Balancing by charge means making sure that the overall charge is the same on both sides of the equation.

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Answer:

14. 2NH4Cl(aq) + K2S(aq) => 2KCl(aq) + (NH4)2S(aq) 

15. 3KCl(aq) + Na3PO4(aq) = 3NaCl(aq) + K3PO4(aq)

Explanation:

14. 2NH4Cl(aq) + K2S(aq) => 2KCl(aq) + (NH4)2S(aq) 

NH4 = 2

Cl = 2

K = 2

S = 1

15. 3KCl(aq) + Na3PO4(aq) = 3NaCl(aq) + K3PO4(aq)

K = 3

Cl = 3

Na = 3

PO4 = 1