When selecting a photometric technique that is more sensitive to a low concentration of analyte, a laboratory director compares absorbance measuring devices against those that measure fluorescence intensity. Which technique is considered more sensitive in its measurements and why

A silicon atom has four unpaired electrons in its valence shell, two paired electrons in its inner shell, and 14 electrons in all. There are 4 hydrogens it will form covalent bonds with.

The four electrons that make up the "valence" energy level's outermost orbit of the nucleus are given to, taken from, or shared by other atoms. Dependent on their energy level, the electrons orbit the nucleus at various distances. As an illustration, an electron with lower energy would orbit towards the nucleus, whereas an electron with higher energy would orbit farther away. The interaction between the electrons of nearby atoms and those that are the farthest from the nucleus determines how solid structures are created.

The first practical PV devices were made of crystalline silicon, which is still the most used PV material in use today. Grasp how the PV effect functions in crystalline silicon provide us a fundamental understanding of how it functions in all devices, even though various PV materials and designs utilize the effect in slightly different ways.

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Answer:

See below

Explanation:

9 m * 2.16 kg/ m = ___________ kg    ( see how the 'm' cancels out?)

Answer:

5 mg

Explanation:

If one half life is 4 hours, then 3 half lives is 12 hours.

This means that the sample will decay to 1/8 of its original amount.

So, the answer is 40(1/8) = 5 mg.

Answer: Choices B and D

Explanation: Elements are what you see on the periodic table and compounds are the product of you adding elements together. A good trick to find this is to look at capitalization. If it has more than one upper-case letter, it is most likely a compound. Elements either have only one upper-case letter or one upper-case letter followed by a lower-case letter. If we keep this in mind, we see that answers A and C can easily be dismissed. KBr is made with two elements, Potassium and Bromine. That leaves us with B and D, which are both elements.

Therefore, the correct answers are B. Li and D. Ca.

I hope this helps! Pls give brainliest!! :)

When a suitable alkyl halide is treated with a nucleophile, a substitution reaction can occur in which the leaving group is replaced by a nucleophile.

In an elimination reaction , hydrogen halide is removed and a leaving group is expelled, giving an alkene.

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Answer:

D.) electrons are gained and lost.

Explanation:

Redox reactions involve the change in oxidation states of the reactants. Oxidized molecules lose electrons whereas reduced molecules gain electrons. In redox reactions, the oxidation number of oxidized molecules decreases and increases in reduced molecules.

65 * 10^3 CFU's per milliliter of water.

CFU stands for a colony-forming unit. which means that cfu/g is a colony-forming unit in line with gram and CFU/ml is a colony-forming unit in step with milliliter. A colony-forming unit is where a colony of microbes grows on a petri dish, from one unmarried microbe.

Colony Forming devices are a time period from Microbiology. CFU offers an indication of the quantity of residing microorganisms in a liquid. This quantity, determined with the aid of counting the individual colonies, describes the number of cells of organisms within the water, which can be capable of multiplying.

Whilst you do plate be counted of micro organism you are making serial suspension dilution in saline buffer or any other diluent, and then you plate a sure quantity (one hundred microliters on a 9cm Petri plate) you unfold and incubate and then you definitely depend on the range of colonies shaped.

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Answer:

not sure

Explanation:

Goo gle can help for sure lol that's what I do anyway good luck hope you get it right.

As atomic radius decreases, electronegativity increases. This is mostly because a smaller atomic radius represents a stronger hold on the valence electrons.

0.03 g of ethylene glycol (C2H6O7) must be added to 1.00 kg of water to produce a solution that freezes at -5.00C.

[tex]\Delta T_{f} = K_{f} m[/tex]

where,

ΔTf = Change in freezing point

Kf = molal freezing point depression constant of the solvent

m = moles of solute per kilogram of solvent.

Now,

[tex]\Delta T_{f} = K_{f} m[/tex]

[tex]\Delta T_{f} = K_{f} \times \frac{W_2}{M_2} \times \frac{1000}{W_1}[/tex]                 [-5.00°C = 273 + (-5.00) = 268 K] [tex]268 = 1.86 \times \frac{W_2}{62} \times \frac{1000}{0.001}[/tex]                 [1.00 kg = 0.001 g]

[tex]W_{2} = \frac{268 \times 62 \times 0.001}{1000 \times 1.86}[/tex]

     = 0.03 g

Thus from the above conclusion we can say that 0.03 g of ethylene glycol (C2H6O7) must be added to 1.00 kg of water to produce a solution that freezes at -5.00C.

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Answer:

A

Explanation:

when technology has created something for which we don't have an ethical framework is called ethical vacuum .

Answer: A

Explanation: A is the correct answer because when technology has created something in which we do not have an ethical framework yet its a called a vacuum.

36.38 ml of a 0.167 M potassium hydroxide solution is required to neutralize 16.6 mL of a 0.366 M nitric acid solution.

Given that 16.6 mL of a 0.366 M nitric acid solution is neutralized by 0.167 M potassium hydroxide solution.

The balanced equation for the reaction is:

HNO₃ + KOH → KNO₃ + H₂O

From the equation given above,

Mole ratio of the acid, HNO₃ (nA) = 1

Mole ratio of the base, KOH (nB) = 1

From the question:

Molarity of the acid, HNO₃ (Ma) = 0.366 M

Volume of the base, KOH (Vb) =

Molarity of the base, KOH (Mb) = 0.167 M

Volume of the acid, HNO₃ (Va) = 16.6 ml

Now,

MaVa/ MbVb = nA/nB

0.366 × 16.6 / 0.167 × Vb = 1/1

6.0756 = 0.167 × Vb

Vb = 36.38 ml

Therefore, 36.38 ml of potassium hydroxide solution is required for the reaction.

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Answer:

Los metaloides serían los elementos con propiedades intermedias. No existe una definición estandarizada de elemento metaloide ni un consenso completo sobre los elementos que son metaloides. A pesar de la falta de especificidad en el término, es muy utilizado en los textos químicos, tanto educativos como divulgativos o de investigación.

Explanation:

The average atomic mass of the atom that has the following isotopes in the following abundances: 20 10Z 30% , 19 10Z10% , 18 10Z 60% is 18.7.

The average atomic mass of an isotopic element is the weighted average of the atomic masses of the naturally occurring isotopes of an element.

According to this question, the atom has the following isotopes in the following abundances: 20 10Z [30%] = 30/100 × 20 = 6

19 10Z [10%] = 10/100 × 19 = 1.9

18 10Z [60%] = 60/100 × 18 = 10.8

The sum of these masses is the average atomic mass and is calculated as follows:

6 + 1.9 + 10.8 = 18.7

Therefore, the average atomic mass of the atom that has the following isotopes in the following abundances: 20 10Z 30% , 19 10Z10% , 18 10Z 60% is 18.7.

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The answer would be:

In2(SO4)3 (Also known as Indium Solfate).

Answer:

I don't think (NH4)PMo12O40 is written properly, but if it is, there are 4 moles of hydrogen atoms for every 1 mole of (NH4)PMo12O40

Explanation:

1 mole of (NH4)PMo12O40 has 6.02x10^23 molecules of (NH4)PMo12O40.  Each molecule of (NH4)PMo12O40 has 4 hydrogen atoms.  If the molecule is decomposed to just it's elements, there would be 4 moles of hydrogen atoms for every one mole of (NH4)PMo12O40.

The number of moles of hydrogen atoms in one mole of (NH₄)PMo₁₂O₄₀ is 4. Hence, option A is correct.

Moles can be given as the mass of the compound to the molar mass.

Moles = Mass/Molar mass

The subscript to the H in the formula describes the number of hydrogen atom in a molecule.

Thus, 1 molecule of (NH₄)PMo₁₂O₄₀ contains 4 atoms of hydrogen.

1 mole = 6.023*10²³ molecules

1 molecule  (NH₄)PMo₁₂O₄₀ = 4 hydrogen atoms

1 mole  (NH₄)PMo₁₂O₄₀ = 6.023*10²³ * 4 hydrogen atoms

1 mole  (NH₄)PMo₁₂O₄₀ = 4 moles of hydrogen atoms

Thus, the moles of hydrogen atoms present in 1 mole of (NH₄)PMo₁₂O₄₀ is 4. Hence option A is correct.

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Well, the answer is the 4rth one "

50°C"

The compound that is involved in the reaction with silver nitrate to form silver chloride and iron (III) nitrate is Iron (III) chloride.

The displacement reaction is the one in which the more reactive element displaces the less reactive element from the compound forming a new compound.

The formation of silver chloride and iron (III) nitrate was followed by the double displacement reaction. The silver in silver nitrate was replaced by the iron forming iron(III) nitrate, and the chloride from the Iron chloride reacted with silver forming silver chloride.

Thus, the compound that reacts with Silver nitrate in the double displacement reaction is Iron(III) chloride.

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Answer:

2.00 g mL -1

Explanation:

2.00 g mL -1

Answer:

19.3 g / ml

Explanation:

The volume of gold is the increase in the cylinder volume

  volume = 2 ml

   mass = 38.6 g

density =   mass / volume = 38.6 / 2 = 19.3 g / cm^3

175 ml of a 1.6 m solution of KCl is diluted to a new volume of 1.0 L. The new concentration of the solution is 0.28 m KCl.

Hence, Option (B) is correct answer.

Concentration is defined as the measure of how much substance there is mixed with another substance.

To find the concentration use the dilution formula

C₁V₁ = C₂V₂

where,

C₁ = Concentration of starting solution

C₂ = Concentration of final solution

V₁ = Volume of the starting solution

V₂ = Volume of the final solution

Now put the values in above formula we get

C₁V₁ = C₂V₂

1.6 × 0.175 = C₂ × 1.0

0.28 = C₂ × 1.0

C₂ = 0.28

Thus from the above conclusion we can say that 175 ml of a 1.6 m solution of KCl is diluted to a new volume of 1.0 L. The new concentration of the solution is 0.28 m KCl.

Hence, Option (B) is correct answer.

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How much hydrogen chloride acid was used?

72.916 g of hydrochloric acid was used.

Given:

Mass of Zn = 65.39 g

Mass of [tex]ZnCl_{2}[/tex] =136.29 g

Mass of [tex]H_{2}[/tex] = 2 g

Equation:

The chemical equation for the reaction of zinc with hydrochloric acid:

Zn + 2HCl → Zn [tex]Cl_{2}[/tex] + [tex]H_{2}[/tex]

Hydrogen gas is created when zinc combines with hydrochloric acid, which causes the process to bubble ferociously. Another sign that a chemical reaction is taking place is the generation of a gas.

Calculation:

A number of equivalents equate:

Number of equivalents = [tex]\frac{given mass}{Molecular Mass}[/tex] x 1000 x equivalent factor

[tex]\frac{x}{36.458}[/tex] x 1000 x 1 = [tex]\frac{136.29}{136.286}[/tex] x 1000 x 2

[tex]x[/tex] = 36.458 x 2

[tex]x[/tex] = 72.916

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An enzyme is an organic catalyst that can bind to nearly any molecule is an organic catalyst increases the activation energy of a reaction is an inorganic catalyst is a source of energy for endergonic reactions

Enzymes are substances that act as catalysts for living organisms and regulate the rate at which chemical reactions take place without a change in the process. The biological processes that occur in all living organisms are chemical reactions, most of which are controlled by enzymes.

Enzyme functions as an organic catalyst. A catalyst is a chemical that participates in a chemical reaction but is not modified by it. Many enzymes work by lowering the activation energy of the reaction.

Enzymes are called biocatalysts because they speed up the biochemical reactions of living organisms. Enzymes are called biocatalysts because they promote chemical reactions without changing the equilibrium state.

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The most important reaction involved in the reoxidation of NADH is Pyruvate → lactate

Two ATP were generated as a net result of glycolysis, two NAD+ were converted to two NADH + H+, and two glucose molecules were divided into two pyruvate molecules.

Pyruvate will go through a process called fermentation when oxygen is absent.

The NADH + H+ from glycolysis will be recycled back to NAD+ during fermentation, allowing glycolysis to proceed.

NAD+ is converted during the glycolysis process into NADH + H+.

Glycolysis cannot proceed without the presence of NAD+.

The NADH produced during glycolysis will be oxidised to create new NAD+ during aerobic respiration, when it will be used once more in glycolysis.

Pyruvate will undergo oxidation in the absence of oxygen or if an organism is unable to engage in aerobic respiration.

Hence The most important reaction involved in the reoxidation of NADH is Pyruvate → lactate

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The shape allows the flask to be sealed with a bung for heating purposes, while also allowing a researcher the freedom to shake or stir the flask without spilling liquid.

Explanation:

The molarity of the potassium hydroxide solution is 0.150 mol/L.

Molar attention is a measure of the attention of a chemical species, in particular of a solute in an answer, in phrases of quantity of substance consistent with the unit extent of solution.

Molarity (M) is the amount of a substance in a sure volume of answer. Molarity is defined as the moles of a solute according to the liters of a solution. Molarity is also referred to as the molar attention of a solution.

Molarity is the wide variety of moles of solute consistent with the liter of answer. For example, in case you dissolve desk salt in water, salt is the solute, and water is the solution. One mole of sodium chloride weighs 58.44 grams. in case you dissolve 58.44 grams of NaCl in a single liter of water, you have got a one molar solution, abbreviated as 1M.

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The standard free energy change (∆Gº') is the energy released when the products are created from the reactants. The (∆Gº') at 298 K is -5.40kJ.

The standard free energy change is given by the sum of the standard free energies of the products subtracted from the sum of the standard free energies of the reactants, given as,

ΔG = ∑nΔG°products − ∑mΔG°reactants

Given,

ΔG°(NO₂) = 51.84 kJ/mol

ΔG°(N₂O₄) = 98.28 kJ/mol

Substituting values:

ΔG = ∑nΔG°products − ∑mΔG°reactants

= ΔG°(N₂O₄) − 2ΔG°(NO₂)

= 98.28 − 2(51.84)

= - 5.4

Therefore, -5.40 kJ is the standard free energy.

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Answer:

1

Explanation:

1.04/MM = 1.04/39.09 = 0.0266 potassium moles

0.7/MM = 0.7/52 = 0.0133 chromium moles

0.86/MM =0.86/16 = 0.05375 oxygen moles

divide all the moles number by the lowest

0.0266/0.0133=2

0.0133/0.0133=1

0.05375/0.133=4

so the empirical formula is K2CrO4

Strecker synthesis of amino acids:

Aldehyde and ketone are the functional groups that react to form the imine intermediate in the Strecker synthesis of amino acids.

Method of Strecker synthesis:

A method for synthesizing amino acids by the reaction of an aldehyde with ammonia in the presence of potassium cyanide is known as the Strecker amino acid synthesis. α-aminonitrile is produced by the condensation reaction, and this α-aminonitrile is then hydrolyzed to produce the required amino acid. The technique is applied commercially to make racemic methionine from methional.

Although primary and secondary amines also produce substituted amino acids, using ammonium salts only produces unsubstituted amino acids. Similar to this, using ketones in place of aldehydes results in amino acids that are α,α-disubstituted.

Reaction mechanism:

An aldehyde's carbonyl oxygen is protonated in the first phase of the reaction, which is followed by an ammonia nucleophilic attack on the carbonyl carbon. Water is separated from the intermediate iminium ion after a second proton exchange. The iminium carbon is then attacked by a cyanide ion, resulting in an aminonitrile.

The aminonitrile's nitrile nitrogen is protonated in the second step of the Strecker Synthesis, and a water molecule attacks the nitrile carbon. Proton exchange and a nucleophilic attack of water on the former nitrile carbon are followed by the formation of a 1,2-diamino-diol. The protonation of the amino group is then followed by the elimination of ammonia, and eventually, the deprotonation of a hydroxyl group results in the production of amino acids.

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Six-membered cyclic hemiacetals and five-membered cyclic hemiacetals are called, respectively mannoses and xyloses.

Cyclic hemiacetals are those molecules that contain both alcohol and a carbonyl group and can undergo an intramolecular reaction to form a cyclic hemiacetal.

Example of Cyclic hemiacetals are :

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Six-membered cyclic hemiacetals and five-membered cyclic hemiacetals are called, respectively, pyranoses and furanoses.

Hemiacetals are chemical compounds containing hydrogen or organic substituents in their molecules and formed by aldehydes or ketones.

The chemical formula of these hemiacetals compounds may be depicted as RHC(OH)OR'.

In conclusion, six-membered and five cyclic hemiacetals are pyranoses and furanoses.

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The principal quantum number (n): specifies the principal shell of the orbital.

The answer is option D.

The important quantum number (n) describes the dimensions of the orbital. Orbitals for which n = 2 are larger than those for which n = 1, as an example. Because they have got opposite electric costs, electrons are interested in the nucleus of the atom.

The numerals, called essential quantum numbers, imply strength degrees as well as the relative distance from the nucleus. A 1s electron occupies the energy stage nearest the nucleus.

A 2s electron, less strongly certain, spends most of its time farther far from the nucleus.

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