a 1.0 x 102 mol sample of a compound that undergoes a first order process is known to have a half-life of 15 minutes. how many moles of the sample remain after 45 minutes?

The buffer solution made with 0.18 M [tex]NH_{3}[/tex] and 0.27 M [tex]NH_{4}Cl[/tex] has a pH of 5.14.

A buffer solution is an aqueous mixture of a weak acid and either its conjugate base or base itself. When a modest amount of a strong acid or base is applied to it, the pH hardly changes at all. A multitude of chemical applications use buffer solutions to maintain pH at a practically constant value. Numerous living systems use buffering to control pH in the natural world.

A buffer solution, which has a constant pH value, is used to keep the solution's pH within the appropriate range. Buffers come in both acidic and basic varieties.

Given,

The buffer solution made with 0.18 M [tex]NH_{3}[/tex] and 0.27 M [tex]NH_{4}Cl[/tex] and

[tex]k_{b}[/tex] of NH₃ = 1.8 × 10⁻⁵

Then, we know

[tex]pk_{b}[/tex] = - log ([tex]k_{b}[/tex])

       = - log (1.8 × 10⁻⁵)

       = 4.74

Now,

By Henderson equation, We get

pH = [tex]pk_{b}[/tex] +ln [[tex]NH_{4}Cl[/tex] / [tex]NH_{3}[/tex]]

     = 4.74 + ln (0.27 /0.18)

     = 5.14

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Answer: 3

Explanation:

trust

Mass spectrometers may be used to pick out unknown compounds through molecular weight determination, to quantify regarded compounds, and to decide shape and chemical residences of molecules.

The relative abundance of every isotope may be decided the usage of mass spectrometry. A mass spectrometer ionizes atoms and molecules with a high-power electron beam after which deflects the ions via a magnetic discipline primarily based totally on their mass-to-charge ratios ( m / z m/z m/z ). In a pure sample of an element, the mass of that element is represented as an m/z ratio and can be used to identify the element. Also, identification of an element can be done by calculating the average atomic mass from the mass spectrum data.

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Answer: the number of moles of PbCl2 produced when 16 moles of AlCl3 are consumed is 24 moles.

Explanation: To determine the number of moles of PbCl2 that are produced when 16 moles of AlCl3 are consumed, you will need to balance the chemical equation and use the coefficients in front of each compound to determine the mole ratio.

The balanced chemical equation for the reaction is:

3Pb(NO3)2 + 2AlCl3 → 3PbCl2 + 2Al(NO3)3

Once the equation is balanced, you can use the coefficients in front of each compound to determine the mole ratio. In this case, the coefficient for PbCl2 is 3, and the coefficient for AlCl3 is 2, which means that there is a 3:2 mole ratio between these two compounds. This means that for every 2 moles of AlCl3 that are consumed, 3 moles of PbCl2 are produced.

To calculate the number of moles of PbCl2 produced when 16 moles of AlCl3 are consumed, you can divide the number of moles of AlCl3 by the mole ratio:

moles PbCl2 = 16 moles AlCl3 / (3 moles PbCl2 / 2 moles AlCl3)

= 16 moles AlCl3 / (3/2)

= 24 moles PbCl2

The valence electronic configuration of group 17 is s² p⁵, and that for group one is s¹ and group 16 is s² p⁴. For group 3 -12 the valence electrons fill in d - orbitals. and for group 2 it is s². for group 13- s² p¹. For lanthanides and actinides, the valence electrons fill in f- orbitals.

The filling of electrons of an atom from the lower energy level to the higher energy level is called its electronic configuration. The group number for atom with  3 and more electrons are 10 added to these numbers.

For group 15, there are 5 valence electrons and the valence electronic configuration is :  s² p³.

For group 18 :  s² p⁶.

For group 16 : the valence configuration is s² p⁴. And for group 17 it is s² p⁵. Group 1 and 2 have the valence electronic configuration as  s¹ and s² respectively.

Group 14, the configuration is s² p² and the that for group 13 is s² p¹.  Elements of group 3 - 12 are d - block elements. The valence electrons of  these elements fall in d- orbital.

Similarly lanthanides and actinides are f - block elements. Their valence electrons are filled in f- orbitals.

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Al₂O₃ is used as an adsorbent, desiccating agent, and catalyst, and in the manufacture of dental cements and refractories.

Aluminium oxide is used for its hardness and strength. It is widely used as an abrasive, including as a much less expensive substitute for industrial diamond. Many types of sandpaper use aluminium oxide crystals.

Aluminium is a chemical element having the atomic number 13, and chemical symbol Al. Alumina is a chemical compound having the chemical formula Al₂O₃. Therefore, the key difference between aluminium and alumina is that the aluminum is a chemical element, and alumina is an aluminium containing compound.

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The Enthalpy of the reaction ΔHrxn is calculated - 794 KJ.

Reaction :

Ca(s) + Cl₂(g) → CaCl₂(s)      

Mole of Ca = Mass of Ca / Molar mass of Ca

Where, Mass of Ca = 1.25 g

            Molar mass of Ca = 40.08 g/mol

Mole of Ca = [tex]\frac{1.25 g}{40.08 g/mol}[/tex] = 0.0311876 mol

Now, Mass of water, m = 150 g

Initial temperature of water, T₁ = 20.0°C

Final temperature of water, T₂ = 53.5°C

ΔT = T₂ - T₁

ΔT = 53.5 - 20

ΔT = 35.5°C

Specific heat capacity of water, Cp(H₂O)

Cp(H₂O) = 4.18 J/g · °C

We have, heat absorbed by water (q)

q = m · Cp(H₂O) · ΔT

q = 150 g × 4.18 J/g·°C × 35.5 °C

q = 24766.5 J

q = 24.7665 KJ

∴ Heat absorbed by water = 24.7665 KJ

Now, this heat is released by 1.25 g (0.0311876 mol) of Ca.

Using unitary method :

 0.0311876 mol of Ca released 24.7665 KJ heat

∴ 1 mol of Ca released (?) heat

    = [tex]\frac{24.7665}{0.0311876}[/tex]  = 754.11 KJ heat released by 1 mol of Ca

Therefore, Enthalpy of the reaction,

           ΔHrxn = - 794 KJ  (here, minus sign indicates heat is released)

Therefore, the Enthalpy of the reaction ΔHrxn is calculated - 794 KJ.

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If 50 g of potassium nitrate is added to 100 g of water at 30 degrees Celcius, 30 gram of potassium nitrate will not dissolve.

A solubility curve is a curve that is produced when the amount of solute that dissolves in a given volume of solvent is plotted against the temperature of the solution formed.

A solubility curve can be used to predict the amount of a given solute that will dissolve in a given amount of solvent at a particular temperature.

The solubility curve of potassium nitrate is shown in the attachment.

At 30°C, the solubility of potassium nitrate is 20 g/100 g of water.

Hence, the amount of potassium nitrate that will remain undissolved when 50 g of it is added to 100 g of water at 30°C will be:

Amount left undissolved = 50 - 20 g

Amount left undissolved = 30

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Lattice energy relates to the attraction between ions and the stability of an ionic compound in which lattice energy increases for ions with higher charges and shorter distances between ions.

Lattice energy is a measure of the strength of the ionic bonds in an ionic compound. It provides insight into several properties of ionic solids including their volatility, their solubility, and their hardness.

For example, when sodium ion (Na+) combines with chloride ion (Cl–), sodium chloride (NaCl) crystal forms, and 787.3 kJ of energy is released. Another example, when calcium ion (Ca2+) combines with oxide ion (O2-), calcium oxide (CaO) crystal forms, and 3414 kJ of energy is released.

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The volume of hydrogen chloride gas that will be produced when 163.7 L of hydrogen gas reacts with excess chlorine gas is 327.4 L

First, we shall obtain the balanced equation for the reaction. This is shown below:

H₂(g) + Cl₂(g) -> 2HCl(g)

From the balanced equation above,

1 L of H₂ reacted to produce 2 L of HCl

With the above information, we can obtain the volume of hydrogen chloride gas, HCl produced when 163.7 L of hydrogen gas reacts. Details below:

From the balanced equation above,

1 L of H₂ reacted to produce 2 L of HCl

Therefore,

163.7 L of H₂ will react to produce = 163.7 × 2 = 327.4 L of HCl

Thus, the volume of hydrogen chloride gas produced is 327.4 L

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Average atomic mass of X is 35.22 amu

What will be the average atomic mass?

The average atomic mass of X will be closer to 35

Let Isotope X³⁵ be A

Let Isotope X³⁷ be B

Let Isotope X³⁸ be C

According to the given question:

The average atomic mass of X can be obtained as follow:

For isotope A (X³⁵):

Mass of A = 35 amu

Abundance of A (A%) = 90%

For isotope B (X³⁷):

Mass of B = 37 amu

Abundance of B (B%) = 8%

For isotope C (X³⁸):

Mass of C = 38 amu

Abundance of C (C%) = 2%

Atomic mass of X =?

Atomic mass = [(mass of A × A%)/100] + [(mass of B × B%)/100] + [(mass of C × C%)/100]

= [(35 × 90)/100] + [(37 × 8)/100] + [(38 × 2)/100]

= 31.5 + 2.96 + 0.76

Average atomic mass of X = 35.22 amu

Therefore, average atomic mass of X will be closer to 35

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The neutrons and protons in atoms' nuclei are held together by an extremely potent, appealing short-range (10–15 m) force called the strong nuclear force.

The forces that occur between two or so more nucleons are referred to as nuclear forces, nuclear interactions, or strong forces. In atomic nuclei, they link protons and neutrons, or "nucleons." The chemical bond that holds atoms in molecules together is about ten billion times weaker than the nuclear force.

Positive-charged protons and straightforwardly charged neutrons are created when the strong nuclear force brings together both positively and negatively quarks. In the atomic nucleus, protons and neutrons are also held together by the strong nuclear force. Complex atoms were made possible by the weak nuclear force.

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A 6.00-cm-diameter sphere with a mass of 89.3 g is neutrally buoyant in a liquid will be  5358 n.

The propensity of an element to float in such a fluid is known as buoyancy. The buoyant force is an upward force that all liquids as well as gases in the absence of gravity apply to any object submerged in them.

the formula Fb=Vg to determine the buoyant force. F b =  dV g, where F b is still the buoyant force expressed in Newtons, would be the fluid density expressed in kilograms per cubic metre, V is the volume of the displaced fluid expressed in cubic meters, and g would be the acceleration brought on by gravity.

Put the values in formula:

F b =  dV g,

Fd = 6.00-cm × 89.3 g × 10

Fd = 5358 n

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a. Atomic radius is a measure of the size of an atom, typically defined as the distance from the center of the nucleus to the outermost valence electron.

b. An electron shell is a region of space around the nucleus of an atom where electrons are most likely to be found.

c. As more electrons and shells are added to an atom, the overall size of the atom increases.

d. The trend in atomic radius is that it generally decreases as we go across a period (from left to right) and increases as we go down a group (from top to bottom) on the periodic table.

Lithium and sodium are both alkali metals and have similar electronic structures, with one valence electron in the outermost electron shell. They differ in the number of protons and neutrons in their nuclei, which affects the overall size of the atom. Lithium has three protons and four neutrons in its nucleus, while sodium has 11 protons and 12 neutrons. As a result, sodium is larger than lithium, with a larger atomic radius.

When more electrons and shells are added to an atom, it will increasing the atom size. This is because the additional electrons are farther from the nucleus and contribute to the overall size of the atom. Additionally, as more electron shells are added, the shielding effect of the inner electrons increases, which means that the outer electrons experience less attraction to the nucleus and are therefore less tightly bound. This can also contribute to the overall size of the atom.

Atomic radius is that it generally decreases as we go across a period (from left to right) and increases as we go down a group (from top to bottom) on the periodic table. This is because as we go across a period, the number of protons in the nucleus increases, which increases the overall positive charge and attracts the valence electrons more strongly. This causes the valence electrons to be more closely bound to the nucleus, leading to a smaller atomic radius. As we go down a group, the number of electron shells increases, which increases the size of the atom overall. Additionally, the outermost valence electrons are farther from the nucleus and experience less attraction, which also contributes to the overall increase in size.

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The partial pressure of the neon that is contained in a container is 3.75 atm.

The given parameters are written as follows:

No. of moles of Ne , n = 5 mol

No. of moles of N2 , n' = 3 mol

Total pressure , P = 6 atm

The mole fraction of any component of a mixture is the ratio of the number of moles of that substance to the total number of moles of all substances present. In a mixture of gases, the partial pressure of each gas is the product of the total pressure and the mole fraction of that gas.

Mole fraction of Ne , X = n / (n+n' )

                                  = 0.625

Mole fraction of N2 , X' = n' / (n+n' )

                                    = 0.375

Partial pressure of Ne , p = X * P

                                     = 0.625 * 6

                                     = 3.75 atm

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Chemical combination of two or more atoms that form a specific chemical compound is called Molecule.

molecule is two or even more atoms posted a link together through synthetic bonds that create the initial volume of a material that retains its properties and composition. Chemistry is constructed on molecules. Molecules are recognised by the component symbol and a subscript indicating the number of atoms. A substance created by the synthetic union of two or more distinct elements. Water (H2O), which is made from the elements hydrogen and oxygen, and table salt (NaCl), which is decided to make from the elements sodium and chloride, are two examples of compounds.

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A structural formula depicts the bonds between the atoms using lines. Most or all of the bonds are omitted in a condensed structural formula. A structural formula identifies the atoms in a molecule. It also demonstrates how they are related to one another.

A condensed structural formula is a method of writing organic structures so that they can be typed in a single line of text.It depicts all atoms but excludes vertical bonds and most or all horizontal bonds.Parentheses in a condensed structural formula indicate that polyatomic groups within a formula are attached to the nearest non-hydrogen atom on the left.

A carbon skeleton can be made up entirely of carbon-hydrogen bonds, as in propane: Propane is made up of three carbon atoms that are held together by single bonds. Propane's chemical formula is C3H8 C 3 H 8. There are four types of carbon skeletons. Skeletons are commonly found as branched, straight chain, or rings. Carbon skeletons can be drawn with or without the presence of atom letters. Carbon skeletons represent a molecule's diversity.

The ball and stick model is a molecular model in which spheres and rods are used to depict a molecule. The spheres represent the atoms of the molecule, and the rods represent the chemical bonds that connect the atoms. These are three-dimensional designs. This model can also be used to represent double and triple bonds.

A space-filling model is a molecular model in which spheres are used to represent a molecule. Unlike the ball and stick model, this model only uses spheres to represent atoms; no rods are used to represent chemical bonds between atoms. The spheres are instead full-sized. In this model, the sphere radii are proportional to the atom radii.

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Proteins, nucleic acids, and polysaccharides are examples of biopolymers; lipids are not. They don't contain repeated monomer units. Since lipids are mostly composed of carbon and hydrogen atoms, they are typically nonpolar. Their structures might also contain phosphate, oxygen, or nitrogen atoms.

How do the other three macromolecules compare to lipids?

Lipids. Lipids don't form long sequences made up of identical or repeating smaller units, unlike the other macromolecules, and they are not soluble in water. The fats you eat are triglyceride molecules, which are made up of three fatty acids bound to a glycerol.

What distinguishes lipids from the other three classes?

Lipids, which are shorter than the other three and have a higher energy content, are not polymers. Our cell membrane contains a number of crucial lipids. Additionally, lipids have a higher energy density per gram than carbohydrates, yet carbohydrates are easier to digest and release energy from than lipids.

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You are researching a substance called remerol, which dissolves in hexane but not in water. Non-polarity is remerol.

Because it dissolves in hexane, a nonpolar solvent, but not in the water, remerol is nonpolar (a polar solvent).

Polar breaks down polar. Similar to this, neither polar nor non-polar will dissolve the other. Hexane's structure consists only of carbon-hydrogen bonds since both carbon and hydrogen have nearly identical electronegativities. Water is actually quite polar, whereas hexane is incredibly non-polar. We can therefore conclude that remerol is non-polar if we are not soluble in polar. If we are non-polar and soluble, it follows that morality is also non-polar. There are therefore only two possibilities: either it is non-polar because it dissolves in hexane, a polar solvent but not in the water, or it is a non-polar solvent. Because hexane is a non-polar solvent, that is illogical. Let's examine the alternate hypothesis. It is true that remerol is non-polar because it dissolves in hexane, which is a non-polar solvent, but not in water, which is a polar solvent.

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When 1-butanol is reacted with p/i2, the resulting molecule is ch3ch2ch2ch2i.

A metabolite generated or discovered in Saccharomyces cerevisiae is 1-butanol. A hydroxy group is swapped for hydrogen of one of the methyl groups in the primary alcohol known as butane-1-ol, which is butane. It is created by gut microorganisms in humans at tiny levels. It functions as a protic solvent as well as a human and mouse metabolite. It is a short-chain primary fatty alcohol, a primary alcohol, and an alkyl alcohol. A clear liquid, n-butyl alcohol has no color. Utilized in the production of organic chemicals, plasticizers, detergents, etc.

As a result, choice E is the right response.

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The number of moles in 17.9 g of  mg(oh)2 is 0.305 mol

The number of moles of a substance can be determined by taking the ratio of the given mass and the molar mass of that substance. The mathematical expression to calculate the number of moles is as follows

number of moles is the ratio of given mass by molar mass

Number of moles= [tex]\frac{Given \mass\ (g)}{Molar\ mass\ (g/mol)}[/tex]            ⋅⋅⋅⋅⋅⋅(1)

The given mass of antacid magnesium hydroxide (Mg(OH)2) is 17.8 g.

The molar mass of Mg(OH)2 is 58.3197 g/mol.

Now , substitute these values in equation (1) to get the number of moles of antacid magnesium hydroxide as follows:

Number of moles = [tex]\frac{17.8\ moles}{58.3197\ g/mol}[/tex]

 =>0.305 mol

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Answer:  330.7 jule energy

Analyze radioactive decay with the half-life calculator.

The half-life sign is t12. For instance, if 100 mg of a medication with a 60-minute half-life is consumed, the following is projected to occur: 50 mg remain 60 minutes after injection. After 120 minutes of ingestion, 25mg is still active.

Ordinarily, seconds are the unit. But it largely depends on the circumstance. If uranium-238 is brought up, you will be discussing a half life measured in the billions of years. In contrast, the half-life of a muon will be measured in seconds or microseconds.

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Answer:

D)Calcium

Hope it help and is this the master A&P chapter 6?

ANSWER:-

2Ag(aq)++Cu(s)→2Ag(s)+Cu(aq)+2

The copper wire dipped in the solution acquires a silver coating because b. Ag+ oxidizes Cu to Cu2+ C u 2 + . This is because, according to the reactivity series of metals, copper is a more reactive metal compared to silver.

Explanation:

i hope this helps

Option - C : Doctors use an ECG to check the functioning of the heart.When preparing to obtain a 12-lead ECG, the "LL" and "RL" electrodes should be placed on the thighs or ankles.

The 12-lead ECG is a non-invasive but extremely valuable diagnostic tool that records the electrical activity of the heart as waveforms.

An ECG, when properly interpreted, can detect and monitor a wide range of heart conditions, from arrhythmias to coronary heart disease to electrolyte imbalance.

Huge advances in the recording and interpretation of ECG have been made since the first telecardiogram was recorded in 1903. The 12-lead ECG is still used as a standard diagnostic tool by paramedics, EMTs, and hospital personnel today. A 12-lead ECG provides a comprehensive picture of the heart's electrical activity by recording data from 12 different angles. Consider the ECG interpretation to be 12 different points of view on an object woven together to create a cohesive story.

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