Nuclear decay occurs according to first-order kinetics. What is the half-life of polonium-218 if a sample decays from 55. 4 g to 31. 7 g in 2. 50 minutes?.

The solubility (in g/l) of caso4(s) in 0.300 m na2so4(aq) at 25°c is 0.016762 g/mol.

Solubility is defined as the maximum amount of a substance in an effort to dissolve in a given quantity of solvent at a special temperature. Solubility is a characteristic asset of a particular solute-solvent combination, and special substances have significantly differing solubilities.

Solubility of CaSO₄; K_sp = 4.93 × 10⁻⁵

Concentration of Na₂SO₄ = 0.4 M

The ionic equation of CaSO₄ is given as;

CaSO₄ ⇒ Ca²⁺ + SO₄²⁻

Now, the formula for solubility ,

K sp = [A⁺]ᵃ × [B⁻]ᵇ

Thus, plugging in relevant values into the solubility equation -

4.93 × 10⁻⁵ = Ca²⁺ × 0.4

Ca²⁺ = ( 4.93 × 10⁻⁵)/0.4

Concentration of Ca²⁺ = 12.325 × 10⁻⁵ M

The molar mass of CaSO₄ =  136 g

Hence, solubility of CaSO₄ in 0.4M of Na₂SO₄ is 12.325 × 10⁻⁵ M × 136 g/mol = 0.016762 g/mol

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The same amount of added energy in water not increase its temperature as much as in ethanol because of temperature difference.

What is temperature?
The physical concept of temperature expresses in numerical form how hot or cold something is. A thermometer is used to determine temperature. Thermometers are calibrated using a variety of temperature scales, which historically defined various reference points as well as thermometric substances. The most popular scales are the Celsius scale, also known as centigrade, with the unit symbol °C, the Fahrenheit scale (°F), as well as the Kelvin scale (K), with the latter being primarily used for scientific purposes. One of the seven units inside the International System of Units is the kelvin (SI).

The average kinetic energy of all the atoms or molecules that make up a substance is how we define temperature in chemistry. A substance's constituent particles do not all possess the same kinetic energy. The distribution of the particles' kinetic energy at any particular moment can be used to describe it.

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The solution pH range is based on the given indicators:

Alizarin yellow- Yellow: 10 to 12

Bromocresol Green - blue: 3.8 to 5.4

Bromothymol Blue - green: 6.0 to 7.6

Methyl orange - yellow: 3.1 to 4.4

A pH indicator can be described as a halochromic chemical compound added in small amounts to a solution so the pH of the solution can be determined by changes in absorption or emission properties.

pH indicators are employed in titrations in analytical chemistry and biology to calculate the extent of a reaction. Because of the determination of color, pH indicators are susceptible to giving imprecise readings.

Alizarin yellow has a pH range of 10 to 12 where 10 for yellow and 12 for red. Bromocresol Green have a pH range of 3.8 to 5.4

Bromothymol Blue has a pH range of 6.0 to 7.6 where 6.0 for Yellow and 7.6 for Blue color. Methyl orange has a pH range of 3.1 to 4.4 where 3.1 is for red and 4.4 is for yellow color.

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The orbitals that are used are 2p and 3p orbitals and there two sigma and a pi bond present in nitrosyl chloride.

We know that atomic orbitals are the regions in space that we can be able to obtain or find the electron in an atom. In this case we can see that we are talking about the compound that we call nitrosyl chloride.

In this compound, we have to know that the atomic orbitals that are involved in the bond are the 2p and 3p atomic orbitals of nitrogen, oxygen and chlorine respectively. Since we have one double and one singe bond, we have two sigma bonds and one pi bond.

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The correct ones are:

The silver substance is silver (Ag) and the brown substance is bromine (Br).

Silver is a monovalent inorganic cation, a silver cation, a monoatomic monocation, and an elemental silver. Cations and anions are held together by electrostatic forces to form ionic solids. Ionic solids are hard, brittle, and have high melting points due to the strength of these interactions.

A bromine compound is a molecule formed by the combination of two bromine atoms. Br2 is a reddish-brown liquid that is never found in its elemental form, but rather in inorganic compounds known as bromides and natural organo-bromine compounds.

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SiO₂ formed as a precipitate.

Elemental silicon is oxidized by O₂ to give a compound which dissolves in molten Na₂CO₃ . When this solution is treated with aqueous hydrochloric acid, SiO₂ formed as a precipitate.

Mechanism 1

1. Si     +     O₂    →    SiO₂

2. SiO₂     +     Na₂CO₃  →  CO₂ + Na₂SiO₃

3. Na₂SiO₃   +   2 HCl (aq)   →  2 NaCl + H₂O (l) + SiO₂

In chemistry, a stable shaped via a change in a solution, frequently due to a chemical reaction or change in temperature that decreases solubility of a stable. In meteorology a precipitate is liquid or strong water.

Hence, SiO₂ formed as a precipitate.

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Allotrope 1 has the higher melting point because it lacks the covalent bonds between phosphorus atoms that are present in allotrope 2.

Allotropes of solid phosphorus are different forms of the element which differ in their molecular arrangement and structure. Allotrope 1 is a more stable form and has a higher melting point than that of allotrope 2 due to the absence of covalent bonds between the phosphorus atoms in allotrope 1.

The structure of allotrope 1 is an ordered arrangement in which the phosphorus atoms form a three-dimensional lattice. This lattice structure is held together by strong Van der Waals forces, which are electrostatic attractions between the atoms. This structure is more stable than that of allotrope 2 and has a higher melting point due to the increased strength of the interatomic forces.

In contrast, the structure of allotrope 2 is much less ordered, and the phosphorus atoms are held together by covalent bonds. This structure is not as stable as that of allotrope 1 and has a lower melting point. The covalent bonds between the phosphorus atoms are much weaker than the forces in allotrope 1, and consequently the melting point of allotrope 2 is lower.

This question is incomplete, so I am attaching the image that contains the information needed to answer it.

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Cesium Sulfite Chemical Formula:

Cs2SO3

Pipeline transportation is only available for specialist goods like liquids and gases.

Delicate, invisible particles that are constant motion and layer on top of one another make up liquids. The particles are held together by cohesive forces, yet they are not firmly adhered to one another as in a solid. Despite touching one another, the particles can still pass freely one another.

An liquid is still a sample of stuff that adopts the shape of the container it is stored in and develops a defined surface when gravity is present. The state, or situation, of substance having this attribute is also referred to as liquid.

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the geometry around the central atom in the following molecular model of  nitrate d) trigonal pyramidal

The bond angle is slightly less than 109.5 degrees, or roughly 107 degrees, for trigonal pyramidal geometry. When the electron-pair geometry is tetrahedral for bent molecular geometry, the bond angle is roughly 105 degrees.

Due to the additional repulsion from the lone pair, trigonal pyramidal geometries have a bond angle that is less than 109.5°. The single lone pair is located at the location of the fourth bond in the tetrahedral structure, on top of the molecule. The bent geometry is the last geometry for the fourth electron group.

Groundwater frequently contains nitrate, which, if consumed in high concentrations, can have detrimental effects on health. Nitrate has no flavor, odor, or color. Nitrate that occurs naturally in small amounts can be normal, but large amounts can contaminate groundwater.

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Experimental evidence of Atomic energy by Hydrogen bright line spectrum

The hydrogen bright line spectrum provides evidence by showing different colours which are having different wavelengths.

What is Hydrogen Bright Line Spectrum?

The Rydberg formula has been used to determine the wavelengths of several spectral series that have derived from the emission spectrum of atomic hydrogen. These spectral lines that have been seen are the result of electron transitions between two energy levels within an atom. The development of quantum mechanics was greatly aided by the Rydberg formula's classification of the series. In astronomical spectroscopy, the spectral series are crucial for determining red shifts and detecting the existence of hydrogen.

Experimental evidence of Atomic energy by Hydrogen bright line spectrum

The hydrogen bright line spectrum provides evidence by showing different colours which are having different wavelengths.

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Answer:

9.68x10^21 molecules of nitrogen

Explanation:

I will assume that r.t.p. is supposed to be STP, Standard Temperature and Pressure.  rtp might refer to room temperature and pressue, but no value is given for room temperature, so let's assume standard temperature (0 degrees Celsius).  Here is a marvelous, and useful, property of gasses at STP:  One mole of gas at STP occupies 22.4 liters.  Let's make that a conversion factor:  (1 mole/22.4 liters).

We have the volume of gas at STP:  360 cm^3.  Convert that into liters:

(360cm^3)*(1 ml/cm^3)*(1 liter/1000 ml) = 0.360 liters(L)

Now use the conversion factor from above to convert the volume of gas into moles of gas:

 (0.360L)*(1 mole/22.4 liters) = 0.0161 moles of gas

By definition, 1 mole is 6.02x10^23 particles, or molecules of the gas.

Convert moles of the gas to molecules:

(0.0161 moles)*((6.02x10^23 molecules)/mole) = 9.68x10^21 molecules of nitrogen.

P1V1T1=P2V2T2 Add 273 to convert degrees Celsius to Kelvin:

∴200×25/298=250×V2/273, ∴V2=200×25×273/298×250, ∴V2=18.32L

The basic formula for volume is length, breadth, and height, as opposed to length, width, and height for the area of a rectangular shape. The calculation is unaffected by how you refer to the various dimensions; for instance, you can use "depth" instead of "height."

Volume, which is measured in cubic units, is the 3-dimensional space occupied by matter or encircled by a surface. The cubic meter (m3), a derived unit, is the SI unit of volume.

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The change in the activation energy barrier is the same: 27.6 kJ/mole.

By reducing the activation energy, a catalyst can speed up a process. In the case of this question, the activation energy is reduced by 27.6 kg per mole, which unquestionably speeds up the reaction.

However, a catalyst does not disrupt the equilibrium because it clearly affects both the forward and backward reaction rates as shown in the picture attached below.

As a result, the forward reaction's activation energy is reduced by 27.6 kJ/mole. Then perhaps the activation energy barrier, 27.6 KJ/mole for the reverse reaction, does not change. Consequently, the addition of a catalyst has no effect on the equilibrium.

Therefore, the activation energy barrier remains constant at 27.6 kJ/mole.

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Straight-chain alkane undecane has 24 hydrogen atoms in it.

10 carbon atoms and 22 hydrogen atoms are covalently linked together to form the hydrocarbon decane. Decane is a member of the enormous organic family known as alkanes. The only atoms in the hydrocarbon molecules of the alkane family are carbon and hydrogen.

Consequently, the alkyne with 16 hydrogen atoms has the formula C9H16 C 9 H 16. Alkenes are hydrocarbons with a double bond connecting the carbon atoms. Their usual formula is CnH2n, or C n H 2 n. 2n = 44, where n is the number of hydrogen atoms.

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The relative abundance of Li-6 =0.0749 = 7.49%

The relative abundance of Li-7 =1 - 0.0749 = 0.9251 =92.51%

Formula used to calculate average atomic mass follows:

Avg atomic mass = ∑(atomic mass of an isotope) x (fractional abundance) ....(1)

Let the fractional abundance of Li-6 isotope be 'x'. So, fractional abundance of  Li-7 isotope will be '1 - x'

For Li-6 isotope:

Mass of  Li-6 isotope = 6.015 amu

For Li-7 isotope:

Mass of  Li-7 isotope =  7.016 amu

Average atomic mass of lithium =  6.941 amu

6.941 amu = x *(6.015) + (1-x) * (7.016)

x= 0.0749

The relative abundance of Li-6 =0.0749 = 7.49%

The relative abundance of Li-7 =1 - 0.0749 = 0.9251 =92.51%

Therefore, the relative abundance of the isotope is 92.51%

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We know that radioactive reactions are first order reaction

For a first order reaction in CHEMICAL KINETICS

Rate Constant = 0.693/(Half Life)

we know that,

Half Life = 500 years

K = 0.693/500

K = 0.001386

For first order,

ln[A] = -Kt + ln[A*]

[A] = concentration of A after time, t

[A*] = initial concentration of A at time, t=0

Kt = 2.303 log {[A*]/[A]}

At half life [A] = [A*]/2

Kt = 2.303 log (2)

(0.001386)t = 2.303 × 0.3010

t = (2.303)(0.3010)/(0.001386)

t = 500.146 years

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The compounds which are most likely dissociated when it is dissolved in the water are Ba(OH)₂, AgNO₃, and KCl respectively.

The compounds which are completely dissociated when it is dissolved in the water are known as strong electrolytes. This compounds form ions when they dissolved in the water. In the given compounds ethanol(C₂H₆O), glucose(C₆H₁₂O₆) is completely soluble but not dissociable. Dichloromethane(CH₂Cl₂) is neither soluble, nor dissociable in the water.

The dissociation of Ba(OH)₂, AgNO₃, and KCl in the water is given as

Ba(OH)₂(aq)→Ba²⁺(aq)+2OH⁻(aq)

For AgNO₃

AgNO₃(aq)→Ag⁺(aq)+(NO₃)⁻(aq)

For KCl

KCl(aq)→K⁺(aq)+Cl⁻(aq)

Therefore, the compounds which are most likely dissociated when it is dissolved in the water are Ba(OH)₂, AgNO₃, and KCl respectively.

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For isothermal process dq=-dw=-300J  dU=0 , for adiabatic process  dq=0 so dU=dw=300J.

What is isothermal process?

In this process the change in temperature is zero through out. So dT=0

What is adiabatic process?

The change in heat is zero through out. So dq=0

From first law of thermodynamics internal energy dU=dq+dw,

for isothermal process dT=0 and dU=n[tex]C_{v}[/tex]dT so dU=0 thus dq= - dw,= -300J.

for adiabatic process dq=0, so dU=dw=300J

What is internal energy ?

Any system for the virtue of its existence have  energy known as internal energy.

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The fifth electron, or IE5, would have a very high ionization energy. Which ionization energy for silicon atoms will significantly rise from the previous ionization energy?

Ionization energy: how is it calculated?

The smallest energy of light quanta (photons) or electrons accelerated to a specified energy that will liberate the least bound atomic electrons is used to calculate the ionization energy of atoms, abbreviated as Ei. On individual atoms, the measurement is carried out in the gas phase.

Why does the ionization energy increase?

On the periodic table, the first ionization energy typically climbs across a period from left to right. The higher nuclear charge results in a closer bond between the outermost electron and the nucleus.

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The organic products of the reaction shown in the prsence of hcl and H2O.hydrogen on oxygen and nitrogen where appropriate and  charges where needed.

Methane, widely known as natural gas, has a healthy substitute in hydrogen. According to estimates, it makes about 75% of the universe's mass and is the most prevalent chemical element. Huge quantities of hydrogen atoms are present on earth in water, plants, animals, and, of course, people. The energy-producing chemical process known as respiration, which powers the metabolisms of most living organisms, depends heavily on oxygen. Many other organisms, including humans, depend on the oxygen in the air we breathe to maintain life. Plants and several microorganisms produce oxygen during photosynthesis.

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For a molecule with the three electron groups or charge clouds where one of those electron groups or charge clouds is nonbonding, the molecular geometry is Bent.

The molecule having three electron groups, one of those electron groups or charge clouds is non bonding means there is one lone pair of electrons and the two of the electron groups or the charge cloud are in bonding , so according to the VSPER theory the molecular geometry is bent with the angle of 120°. the electron geometry is trigonal planar.

Thus, the molecular geometry with the two bonding electron group and one non bonding electrons group is bent.

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The hydrogens just on carbons close to the carbonyl group have a shift towards carbonyla triple - negative electronegative atoms of about 200 ppm.

What is the name of the carbonyl group?

A carbon atom is double-bonded to the an oxygen atom to form a carbonyl group, that is a chemically active functional group. Aldehydes and ketones, which are typically joined to another carbon compound, are the simplest carbonyl groups. Many aromatic chemicals have these structures, which contribute to flavor and fragrance.

Which structural subunits make up carbonyls?

Carbonyl-containing functional groups include aldehydes and ketones. The primary distinction is that for carbon to be a member of these functional groups, it must be doubly bonded to other groups in addition to oxygen. A ketone must have a connection between the carbonyl carbon and

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As more co2 is absorbed into the oceans the pH decreases and the ocean becomes more acidic.

There is more CO2 evaporating into the ocean as a result of human-driven increases in atmospheric carbon dioxide levels. The average pH of the ocean is currently 8.1, which is basic (or alkaline), but when more CO2 is absorbed, the pH drops and the ocean turns more acidic.

What is pH?

pH is a measurement of how acidic or basic an aqueous solution is in relation to other liquids. The phrase, which is frequently used in chemistry, biology, and agronomy, converts hydrogen ion concentrations, which typically vary between 1 and 1014 gram-equivalents per litre, into numbers between 0 and 14.

Therefore, As more co2 is absorbed into the oceans the pH decreases and the ocean becomes more acidic.

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The true statement is b ) NH₄⁺ is a stronger acid than H₂O ( l )

NH₄⁺ + OH⁻ = NH₃ + H₂O .

NH₄⁺ is a conjugate acid of NH₃

OH⁻ is a conjugate base of H₂O .

NH₄⁺ is capable of giving H⁺ to OH⁻ to produce H₂O so it is stronger acid than H₂O .

Had H₂O been stronger , it would have given H⁺ to NH₃ to produce NH₄⁺ but it does not happen .

So NH₄⁺ is a stronger acid than H₂O ( l ).

The stronger the acid, the weaker the conjugate base. This is known as acid-base pairs. For more information check below.

Acid-Base pairs:

A corrosive, inside the Brønsted-Lowry corrosive base speculation, is a substance compound outlined when a corrosive gives a proton to a base all things considered, it is a base with a hydrogen molecule added to it, as in the opposite reaction it loses a hydrogen molecule.

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A is the best choice. Since alcoholism requires lifetime treatment, it is regarded as a chronic condition. Due to its extreme difficulty in treatment, alcoholism is regarded as a chronic condition.

And tends to come back over the course of the affected person's lifespan. An alcoholic is never fully freed from their addiction, even though it can be treated. They must take action and keep in mind that their illness may flare up at any time. Navigate to content To search, click. A chronic condition is a sickness that develops over time or a human health condition that is persistent or has other long-lasting impacts. Alcoholism is generally defined as any drinking of alcohol that causes serious issues with one's mental or physical health.

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The time that is required to deposit the certain grams of copper is 34 min.

The charge that is carried by 2 moles of electrons is 96500 C. The amount of copper deposited is 1.36 g.

Thus, the charge required to deposit 1.36 g copper is calculated as follows:

=1.36 g*63.55 g/mol*96500 C

=4130 C

The current passing in an aqueous solution is 2.00 A.

Thus, the time required to deposit the amount of copper is calculated as follows:

t=q/C

t=4130 C/2.00 A

t=34 min

Thus, the time needed is 34 min.

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32.18 KJ/mol of heat will be released if 0.4501 mol of NH₃ are mixed with 0.200 mol of O₂.

Limiting reagent- The reactant that is totally consumed during a reaction, or the limiting reagent, decides when the process comes to an end. The precise quantity of reactant required to react with another element can be estimated from the reaction stoichiometry.

1 mole of O₂ and 4 moles of NH₃ reacts-

therefore,

A reaction between 0.4501 mole of NH₃ should occur with 0.4501 x 1 / 4 = 0.1013 moles of O₂

O₂ is an excess reagent, and NH₃ is a limiting reagent.

286 KJ/mol of energy are released by 4 moles of NH₃.

0.4501 mole The amount of energy released by NH₃ =286KJ/mol x 0.4501 / 4mol

= 32.1822 KJ/mol of energy

Thus, heat released is -32.18 KJ/mol.

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(D) [tex]Pb^{2+}[/tex]<[tex]NO_{3} ^{-}[/tex]=[tex]K^{+}[/tex] is the right answer for the ions remaining in solution in order of increasing concentration once the reaction has stopped.

What is concentration ?

The no of mol of solute present per litre of solution is known as molarity , for normality we consider no of equivallent of solute per litre of solution.

1 mol of [tex]Pb(NO_{3})_{2}[/tex] gives 2 mol of [tex]KNO_{3}[/tex] here 1.5 mol of [tex]Pb(NO_{3})_{2}[/tex] gives 3 mol of KNO3.

   [tex]Pb(NO_{3})_{2} +K_{2}S- > PbS+ 2KNO_{3}[/tex]

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