when determining the absolute age of a rock, scientists measure the radioactive decay of isotope to isotope. this process is called dating.

FALSE, the isotope carbon-14 decays to nitrogen-14 over a half-life of 5,730 years. these isotopes could be used to determine the age of rocks formed early in the cenozoic era, approximately 60 million years ago.

Having the chemical symbol C and atomic number 6, carbon is an element with the meaning "coal" in Latin. It is nonmetallic and tetravalent, meaning that four of its atom's electrons may be used to create covalent chemical connections. The periodic table's group 14 is where it belongs. Only 0.025 percent of the crust of the Earth is made up of carbon. The bond sequence affects a bond's strength. Because shorter bonds have a higher bond strength than longer bonds, the higher the bond order, the stronger the bonds are. The bond order of carbon dioxide is 2, that of carbon monoxide is 3, and that of the carbonate ion is 1.33.

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Lewis structures are used to show the arrangement of electrons around the valence shell of atoms present in the molecules.

A Lewis dot structure is composed of dots and symbols of the elements. The Lewis structure shows the electrons present on the valence shells of atoms in molecules. We can easily deduce the number of valence electrons in a molecule by simply counting the number of electrons from the molecule.

The Lewis structure of NH₂Cl is clearly shown in the image attached. The lone pairs of electrons are shown by using dots while the bond pairs are shown by using a single dash.

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The box below to the left represents ions in a certain volume of 0.10MHCl(aq). In the box below to the right, representation of ions in the same volume of 0.20MHCl will contain eight dots and eight circles.

The student performs a second titration using the 0.10 M NaOH(aq) solution again as the titrant, but this time with a 20.mL sample of 0.20MHCl(aq) , instead of 0.10 M HCl. the square represents the  0.10 M HCl(aq) solution is contains four dots and the four circles.

Then the square representation of ions in the same volume of 0.20MHCl(aq) is eight dots and the eight circles. the image is attached below with representation of the sots and the circles.

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Answer:

Ca + 2 Na+ + 2 e- ⟶ Ca2+ + 2 Na

Explanation:

The overall reaction is balanced by including the electrons that are transferred in the reaction. The balanced overall reaction is:

Ca + 2 Na+ + 2 e- ⟶ Ca2+ + 2 Na

This reaction shows the transfer of two electrons from calcium to sodium ions, which results in the formation of calcium ions and sodium atoms. This reaction is electrically neutral, with the same number of positive and negative charges on each side of the reaction. Overall, the reaction represents the transfer of electrons from one element to another, resulting in the formation of new chemical species.

total amount of energy required is= 132.6 + 717.9 + 45.42 = 896 kJ to convert 450g of liquid water from 38°C to water vapor at 125 C. The molar heat of vaporization (Hvap) of water is 40.79 kJ/mol. The specific heat for water is 4.184 J/g C, and for steam is 1.99 J/g C.

cslculation-heat energy required to raise the temp of liquid water to 100 C = 317 * 4.184 * 100 = 132632 J =132.6 kJ,mole of water = 317 / 18 = 17.6 mol,heat required for vaporization = 17.6 * 40.79 = 717.9 kJ,Heat required to raise the temp of water vapor to 172 C = 317 * 1.99 * 72 = 45420 J = 45.42 kJ, total heat required  = 132.6 + 717.9 + 45.42 = 896 kJ. The quantity of heat necessary to increase the temperature of one unit mass of a substance by one degree Celsius. The specific heat capacity of a substance is specified as the amount of heat (J) soaked up per unit mass (kg) when its temperature rises 1 K (or 1 °C). The specific heat capacity of a substance is typically calculated by monitoring the heat capacity of a specimen of the material, generally with a calorimeter, and trying to divide by the sample's mass. The average kinetic energy of each molecule increases as the substance heats up.

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The ΔH of the reaction of the formation of N₂O₄ is equal to - 90 KJ.

Hess's law of constant heat summation can be defined as the total enthalpy change while the complete course of a chemical reaction independent of the sequence of steps.

Given, the reactions can be represented as:

N₂ (g) + O₂(g) →  NO                   }   ×1                       ΔH = + 90 KJ

NO (g) + 1/2 O₂ (g)  →  NO₂ (g)    }  × 2                     ΔH = -56 KJ

2NO₂ (g) →  N₂O₄ (g)                   }   × 1                 ΔH = - 58 KJ

The overall reaction of the formation of  N₂O₄ (g)  can be obtained as:

N₂ (g)  +2 O ₂  (g)  →  N₂O₄ (g)

ΔH = 1 × 90  + 2 ×(-56)  + 2 × (-58)

ΔH = = - 90 KJ

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Mass of the pure silver deposited on a metal object made into the cathode of the cell is calculated to be 0.0217 gm.

The process of using electrodeposition to coat an object in a layer of metal is called electroplating .

As we know that, Q = I * t

=0.270 * 72

= 19.44 C

Here Q is quantity of electricity , I is current in amperes = 0.270 A (given)

t is time in seconds (72.0 sec)

As 96500 Coulomb of electricity electrolyzes 1 mole of Ag

then,19.44 C of electricity deposits,

=1/96500 * 19.44

= 0.000201 moles of Ag

Mass of Ag is = number of moles * molar mass

= 0.000201 * 108

= 0.0217 gm

Thus, mass of pure silver deposited on a metal object made into the cathode of the cell is  0.0217 gm.

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At room temperature, granulated sugar is a white, crystalline solid that is soluble in water, has a low melting and boiling point, and is bound together by covalent bonds.

What types of solids have crystal lattices?

Crystalline solids are made up of atoms, polymers, or ions that are arranged in a predictable, three-dimensional pattern. Solids that have a crystal structure include quartz, diamonds, sodium chloride, and others.

What are the characteristics of a crystalline solid?

Solids with crystalline structures have conventional geometries. In these kinds of solids, atoms, molecules, or ions are arranged in long-range order throughout the 3-dimensional network of a crystal. Sodium chloride, quartz, diamond, etc. are few examples. Crystalline solids' characteristics.

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The name of the organic compound shown is methylpropenaoate.

It is an alkanoate.

Esters are organic compounds formed when an organic acid reacts with an organic base.

An example of an ester is alkanoates.

Alkanoates are formed when alkanoates, the alkanoic acids react with alkanols.

In hydrogen ion, an alkanoic acid reacts with the hydroxide ion of the alkanol to form water and the alkanoates are formed as well from the remaining moieties of the alkanol and the alkanoic acids.

The molecule whose structure is shown is an alkanoate.

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12 electrons are transferred in this oxidation–reduction reaction.

What is oxidation-reduction reaction?

Reduction-oxidation is referred to as redox, and a redox reaction is one in which both a reduction reaction and an oxidation reaction occur at the same time. Additionally, it is an acronym for an oxidation-reduction reaction. Let's first talk about each of these two elements independently before returning to how they interact to form a complete redox reaction.

The balanced reaction is

4 Fe (s) + 3 O2 —> 2 Fe2O3 (s)

Oxidation state of Fe changes from 0 to +3 and there are 4 such Fe.

So, it loses 4*3 = 12 electrons

Oxidation state of Oxygen changes from 0 to -2 and there are 6 such Oxygen.

So, it gains 6*2 = 12 electrons

Hence, we can say that 12 electrons are transferred.

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Complete question:

Rust (Fe2O3) forms on abandoned cars such as the one in this photo through a series of reactions between iron in the car and oxygen in the atmosphere.

The unbalanced chemical equation for this reaction is

Fe(s) + O2(g) –> Fe2O3(s)

How many electrons are transferred in this oxidation–reduction reaction?________ electrons

When an atom's oxidation number rises, the reducing agent reduces the atom, and when it falls, the oxidising agent reduces the atom. The oxidising agent is the atom that is reduced, while the reducing agent is the atom that is oxidised.

For instance, the oxygen ion O2+ has an oxidation number of 2 because it can contribute two electrons, whereas the iron ion Fe3+ has an oxidation number of +3 because it can take up three electrons to establish a chemical bond.

Electrons are lost during oxidation. An rise in the substance's oxidation state results from the loss of negative charge. Fe atoms become oxidised to Fe2+ ions after losing two electrons.

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In the citric acid cycle , beginning with one of the molecule of isocitrate and ending with the fumarate, the ATP molecules can made through the substrate-level phosphorylation is one molecule.

In the citric acid cycle, the substrate level phosphorylation is the high energy of the phosphate group in the organic molecule. it transfers to the ADP to produces the ATP. it is the metabolic reaction and form the ATP molecules. The citric acid cycle is called as Krebs cycle also.

Thus, the number of ATP molecules form during the citric acid cycle that start with the one molecule of the isocitrate and end with the fumarate is the one molecule.

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a crystal of iodine, a sonicator, a few drops of performing Grignard reagent.

Sonicators are high-frequency (20 kHz) devices that agitate particles in liquids using ultrasonic radiation.These tools are used to speed up a wide range of procedures, including sample preparation, cell disruption, cleaning, degassing, and mixing.

Small vacuum bubbles are formed in the liquid when low pressure is applied because this causes high-intensity ultrasonic waves to be created.In the high-pressure cycle, bubbles disintegrate as soon as they reach their saturation point.Cavitation is the name of this procedure.

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The sequence of amino acids in a polypeptide chain is the most basic level of protein structure, known as primary structure. Insulin, for example, has two polypeptide chains. Each chain has its own set of amino acids that are assembled in a specific order.

Secondary structure is the next level of protein structure and refers to local folded structures that form within a polypeptide as a result of interactions between backbone atoms.The helix and the pleated sheet are the two most common types of secondary structures.

A polypeptide's overall three-dimensional structure is referred to as its tertiary structure. The tertiary structure of the protein is primarily due to interactions between the R groups of the amino acids that comprise it. Hydrogen bonding, ionic bonding, dipole-dipole interactions, and London dispersion forces are all examples of R group interactions that contribute to tertiary structure. R groups with like charges, for example, repel one another, whereas those with opposite charges can form an ionic bond.

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The total pressure after equilibrium will be 0.854 atm calculated  help of kp.Since the Kp depends on the individual partial pressures of the components in mixture.

N₂O₄ ==> 2NO₂

initial..0.554.........0

change....-p..........+2p

equil....0.554-p.......2p

Total Pressure at equilibrium  = 0.770;

therefore,

0.554-p+2p = 0.770 and this allows  to calculate Kp.

NO₂ is injected to make  the Ptotal equals to 0.906 bar

so that makes 0.906-0.770 = 0.136 bar  being injected.

It would make a new ICE chart with the NO₂ start = 0.136 + old equilibrium pressure of  N₂O₄ = old equilibrium and recalculate the new pressures using the Kp from the first part. You know of course that the reaction will be shifted to  left side

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The mass percent formulas is given as :

mass percent = ( mass of the solute / mass of the solution ) × 100 %

The mass is generally represented in the grams. the mass percent percent mean the weight percent or w/w %. the mass formula is given as follows :

mass percent = ( mass of the solute / mass of the solution ) × 100 %

let us take an example if mass of solute = 7 g and the mass of solvent = 367 g.  the mass percent is given as :

mass of solution = 7 + 367 = 374 g

mass percent = ( mass of the solute / mass of the solution ) × 100 %

                      = (7 / 374) × 100 %

                      = 1.86 %

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The chemical pair that will produce a buffer solution when dissolved in water is HNO2 and NaOH. (Option C)

A buffer solution refers to an aqueous solution which consists of a mixture of a weak acid and its conjugate base, or vice versa. A buffer solution is a solution whose pH only changes slightly when an acid or a base is added to it. For an acid-buffer solution, it consists of a weak acid and its conjugate base. For a basic-buffer solution, it consists of a weak base and its conjugate acid. The HNO2 and NaOH will form a buffer as it is a mixture of weak acid and its conjugate base.

Note: The question is incomplete. The complete question probably is: Which of the following chemical pairs produce a buffer solution when dissolved in water? A) NaOH and HBr B) NaCl and HCl C) HNO2 and NaOH D) NH3 and HCl.

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It is impossible to combine KOH and HI to create a buffer solution.

A buffer solution, also referred to as a pH buffer or hydrogen ion buffer, is an aqueous mixture of a weak acid and its conjugate base, or vice versa. The pH scarcely changes at all when a small amount of a strong acid or basic is added to it. Buffer solutions are used in a wide range of chemical processes to keep pH values almost constant. Buffering is used by many living systems to regulate pH in the natural world. For instance, the bicarbonate buffering system regulates the pH of blood, and bicarbonate also acts as a buffer in the ocean.

The pH of a solution containing a buffering agent can only fluctuate within a specific range, regardless of what else may be in the solution. This is necessary for the enzymes in biological systems to function properly. For instance, the primary mechanism for maintaining the blood's pH between 7.35 and 7.45 is a blend of carbonic acid and bicarbonate found in the plasma component of human blood. Outside of this exact pH range, metabolic diseases called acidosis and alkalosis that finally end in mortality rapidly develop if the necessary buffering capacity is not immediately restored.

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i) Entropy change for the surroundings when 2.13 moles of Fe(s) react at standard conditions is 52.89 K/J.

According to Hess law, “at constant temperature, heat energy changes (enthalpy – ΔHrec) accompanying a chemical reaction will remain constant, irrespective of the way the reactants react to form product”.

Heat of reaction = sum of heats of reaction of products - sum of heats of reaction of reactants or

ΔH0rxn = ∑n×ΔHf0(products)−∑n×ΔHf0(reactants)

= ΔHf0 FeCl2(s) + ΔHf0 H2(g) - (ΔHf0 Fe(s) + 2 *ΔHf0 HCl(aq))

= (-341.8 KJ + 0 KJ)-(2*-167.2 KJ+1*0 KJ)

= -7.4 KJ

the enthalpy change when 2.13 moles of Fe(s) react at standard conditions = 2.13(-7.4) KJ = -15.762 KJ

ΔS°surroundings = -ΔH0rxn /T

= -(-15.762 KJ)/298 K

= 52.89 J/K

ii) Entropy change for the surroundings when 2.23 moles of C2H4(g) react at standard conditions is 341.2 J/K.

According to Hess law,

ΔH0rxn = ∑n×ΔHf0(products)−∑n×ΔHf0(reactants)

= ΔHf0 CH3CH2OH(g) - (ΔHf0 C2H4(g) + ΔHf0 H2O(g)))

= (-235.1 KJ)-(52.3 KJ+(-241.8 KJ)

= -45.6 KJ

the enthalpy change when 2.23 moles of C2H4(g) react at standard conditions = 2.23(-45.6) KJ = -101.688 KJ

ΔS°surroundings = -ΔH0rxn /T

= -(-101.688 KJ)/298 K

= 341.2 J/K

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Each molecule of pyruvic acid has three carbon atoms, while each molecule of carbon dioxide only has one.

Explanation: If we start with one molecule of pyruvate, three carbon dioxide molecules are created during cellular respiration. The first is created by pyruvate dehydrogenase's intermediate step, which transforms pyruvate into acetyl-CoA. When D-isocitrate is changed into alpha-ketoglutarate, the second is created.

If a quadruple bond were to form, it would point away from the two carbon atoms. The other three bonds would need to be severely bent in order for this bond to exist, which is extremely inefficient in terms of energy. Thus, the creation of the quadruple bond is prevented by this strain.

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The total concentration of ions remaining in the solution is 0.0007 M.

To solve this problem, we need to determine the concentration of both magnesium nitrate and sodium hydroxide before the solutions are mixed, and then use the reaction between magnesium nitrate and sodium hydroxide to determine the concentration of ions remaining in solution after the reaction is complete.

To calculate the total concentration of ions remaining in solution after the reaction is complete, we need to first determine the number of moles of each reactant present before the reaction occurs. To do this, we can use the molar mass of each compound to convert the mass of each compound to moles.

First, we can calculate the number of moles of magnesium nitrate present in the 22.02 mL solution:

Number of moles of magnesium nitrate = (1.615 g magnesium nitrate) / (148.32 g/mol magnesium nitrate) = 0.0109 moles magnesium nitrate

Next, we can calculate the number of moles of sodium hydroxide present in the 28.64 mL solution:

Number of moles of sodium hydroxide = (1.073 g sodium hydroxide) / (40.00 g/mol sodium hydroxide) = 0.0268 moles sodium hydroxide

Now that we know the number of moles of each reactant, we can use the balanced chemical equation for the reaction between magnesium nitrate and sodium hydroxide to determine the number of moles of each product that will be formed:

Magnesium nitrate + Sodium hydroxide -> Magnesium hydroxide + Sodium nitrate

1 mole magnesium nitrate + 1 mole sodium hydroxide -> 1 mole magnesium hydroxide + 1 mole sodium nitrate

Since we have 0.0109 moles of magnesium nitrate and 0.0268 moles of sodium hydroxide, the number of moles of each product that will be formed is also 0.0109 moles for magnesium hydroxide and 0.0268 moles for sodium nitrate.

Finally, we can use the number of moles of each product and the total volume of the solution to calculate the concentration of each product in the solution. The total volume of the solution is 22.02 mL + 28.64 mL = 50.66 mL.

The concentration of magnesium hydroxide in the solution is:

(0.0109 moles magnesium hydroxide) / (50.66 mL solution) = 0.0002 M magnesium hydroxide

The concentration of sodium nitrate in the solution is:

(0.0268 moles sodium nitrate) / (50.66 mL solution) = 0.0005 M sodium nitrate

The total concentration of ions remaining in the solution after the reaction is complete is the sum of the concentration of the magnesium ions and the concentration of the sodium ions. The concentration of the magnesium ions is 0.0002 M, and the concentration of the sodium ions is 0.0005 M, so the total concentration of ions remaining in the solution is 0.0002 M + 0.0005 M = 0.0007 M.

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It is a monovalent inorganic ion that belongs to the reactive nitrogen species and is called a nitrogen oxoanion.

What is ion ?

An ion with more than one atom is referred to as a polyatomic ion. One such ion is the nitrate ion! It has one nitrogen atom and three oxygen atoms.

As seen in the graphic accompanying this answer, it is an ion in which there is charge separation. The nitrate ion's Lewis structure, which complies with the octet rule, is represented in the diagrams.Nitrates are an ester family of nitric acid (HNO3) and alcohol molecules. By losing a proton from nitric acid, nitrate is a nitrogen oxoanion. main species found at pH 7.3.

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Uranium is often known as a silvery-white metal in the actinide series of the periodic table. Uranium is softly radioactive because all isotopes of uranium are unstable, with half-lives varying between 159,200 years and 4.5 billion years.

Uranium has the giant atomic weight of the primordially occurring elements and Its hardness is about 70% higher than that of lead and slightly lower than that of gold or tungsten.

Uranium is often found at low levels (a few ppm – parts per million) in all rocks, soil, water, plants, and animals (including humans). generally, Uranium occurs also in seawater and can be recovered from the ocean water.

Significant concentrations of uranium occur in some elements such as uraninite (the most common uranium ore), phosphate rock deposits, and other minerals.

Uranium is a chemical element with atomic number 92 which means there are ninety-two protons in its nucleus.

There are a total number of protons in the nucleus is called the atomic number of the atom and is denoted by the symbol Z. The total amount of electrical charge of the nucleus is, therefore, +Ze, where e (elementary charge) equals 1,602 x 10-19 coulombs.

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N2(g) + 3H2(g) 2NH3 is the reaction's balanced equation (g)

The equation for the reaction's equilibrium constant, k, is k = [NH3(g)]2 / [N2(g)].[H₂(g)]

The concentrations in the sample are in an equilibrium state. So, we may just utilize those in the computation.

0.184 mol/L= [NH3(g)]

0.551 mol/L= [N2(g)]

0.4 mol/L= [H2(g)]

Applying the equation, k = (0.184 mol/L)2 / ((0.551 mol/L) x (0.400 mol/L)3), yields k = 0.960 mol2 L2.

As a result, the reaction's equilibrium constant at 500 °C is 0.960 mol2 L2

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A fundamental property of chemistry called Boyle's Law describes how a gas behaves when it is kept at a constant temperature. The rule asserts that the volume of a gas is inversely proportional to the pressure it exerts at a certain temperature. Robert A. Boyle discovered this relationship in 1662.

This empirical relationship, which Robert Boyle, a scientist, first proposed in 1662, argues that, under constant temperature, the pressure (p) of a given amount of gas changes inversely with its volume (v); in equation form, this means that pv = k, a constant.

Blood flows into the syringe to balance the pressure difference since blood in a vein has a higher pressure than the gas in the syringe. One of the three gas laws that govern the behavior of gases is Boyle's law.

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An electron in a molecule behaves wave-like according to a function called a molecular orbital. Utilizing quantum mechanics, the molecular orbital theory defines the electrical structure of molecules.

What would an example of equilibrium look like?

There are several examples of equilibrium, such as: an open book that is lying flat. a moving object that is moving steadily a chemical reaction takes place where the rates of both the forward and reverse reactions are identical.

What is straightforward equilibrium?

A system is at an equilibrium when all of its external forces are in balance. When a system is in equilibrium, nothing changes.

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UV light is the most popular non-destructive visualization technique for TLC plates. stains from thin layer chromatography.

To see TLC findings for colorless substances, a visualizing approach is required. It will provide a means of seeing these chemicals as well as a Single alkenes do not show up very well on TLC under UV, even when markers are applied, hence this procedure is known as staining the TLC plate. Offer a stain that might be utilized to help a TLC viewer see your goods. Normally, a UV (Ultraviolet) lamp is required to see the various spots, but if the compounds are brightly colored, It is possible to conduct both qualitative and quantitative analyses using thin layer chromatography. Excellent wettability for accurate colorization outcomes.

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At very high pressures, the molecular volume of the gas particles is significant.At moderately high pressures there are significant intermolecular attractions is the statements that correctly account for this given behavior.

An equation of states is PV = nRT. Three variables are P, V, and T. They are variables because they indicate the pressure, volume, and temperature of a gas in a certain condition as well as other physical characteristics. The ideal gas constant (R) is a constant that may be found in chemical literature, and the number of moles (n) may be maintained constant. Moles (n) may be set to PV / RT as follows: n = PV / RT. T / V ratio becomes important because pressure (P), which is directly proportional to T and indirectly proportional to V, depends on it.Volume (V) is a function of T/P, with V being directly proportional to T and indirectly proportional to P. PV is a necessary condition for temperature (T), which is directly proportional to variations in both P and V.

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The pH in each case depends on the relative amounts of acid and base present.

a) Before the addition of HBr:

Number of moles = Mass of substance / Mass of one mole

Number of moles of C5H5N = 25/1000 L × 0.150 M = 0.00375 moles

pOH = -log[0.00375 M]

pOH = 2.42

pH = 14 - 2.42

pH== 11.58

b) After the addition of 12.5 mL of HBr:

Since the reaction is 1:1

Number of moles of HBr = 12.5/1000 L × 0.150 M = 0.00375 moles

The HBr is the limiting reactant

Amount of excess acid = 0.0045 M - 0.00375 = 0.00075 moles

Total volume of solution = 25mL + 12.5 mL = 37.5mL or 0.0375L

molarity of excess H+ = 0.000075 moles / 0.0375 L = 0.002 M

pH = - log[0.002M]

pH = 2.69.

c) After the addition of 19.0 mL of HBr:

Number of moles of acid = 19/1000  × 0.150 M = 0.00285 moles

Number of moles of excess acid =  0.0045 moles  - 0.00285 moles = 0.000165 moles

Total volume of solution =  19.0 mL +  25.0 mL = 44mL or 0.044 L

Molarity of excess acid = 0.00018 moles/ 0.044 L = 0.00409 M

pH = -log[0.00409 M]

pH== 11.58

d) After the addition of 25.0 mL of HBr:

Number of moles of acid = 25/1000  × 0.150 M = 0.00375 moles

We have an equal number of acids and bases hence pH=11.65

e) After the addition of 33.0 mL of HBr:

Number of moles of acid = 33/1000  × 0.150 M =0.00495 moles

We can see that the base is the limiting reactant.

Number of moles of excess base = 0.00495 moles

Total volume of solution = 33 mL + 25 mL = 58mL or 0.058 L

Molarity of excess base = 0.00162 moles/0.058 L = 0.027 M

pOH = -log[ 0.027 M]

pOH = 1.56

pH = 14 - 1.56

pH- = 12.44

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according to the big bang during the very earliest moments of the universe the first photons appeared in the universe Were those released during decoupling (visible today as the cosmic microwave background) and 21 cm radio emissions occasionally emitted by hydrogen atoms.

The Big Bang theory is a physiological concept that explains how the universe is expanding from a dense population and heat state. Various Big Bang cosmic models explain the progression of the visible universe from its earliest known time frames to its global context form. During a talk for a March 1949 BBC Radio broadcast, English astronomer Fred Hoyle is credited with coining the term "Big Bang," saying: "Such theories were predicated on the hypothesis that all of the material in the universe was created inside one big bang at a special time in the distant past."

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