What is the Linnaean system of classification and why is it important? List the 7 levels of the Linnaean classification system. (Pls respond I will give brainliest)

The following statements on HPLC modes are true is more polar compounds elute first in normal-phase HPLC (Option E).

The liquid chromatography (HPLC) is a technique in analytical chemistry employed for the separation, identification, and quantification of elements. It is considered a highly sensitive method, and it works by separating the components in a mixture with the assistance of a solvent under high pressure.

There are two modes of HPLC: Reversed-Phase HPLC (RP-HPLC) and Normal-Phase HPLC (NP-HPLC). In RP-HPLC, a nonpolar stationary phase, such as C18, is used, and polar solvents, such as water, are used as mobile phases. Polar stationary phases, such as silica gel, are used in NP-HPLC, while nonpolar solvents, such as hexane, are used as mobile phases.

More polar compounds have a greater affinity for the polar stationary phase than less polar compounds, which have a higher affinity for the nonpolar mobile phase in NP-HPLC. As a result, less polar compounds elute first in normal-phase HPLC.

Thus, the correct option is E.

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Answer:

Last Column is:

Explanation:

98  ,   7.8   ,   371    and     0.98

The materials price and quantity variances for the month is  $1,200. The labor rate and efficiency varionces for the month is $2,080.

1. Calculation of Materials price variance and materials quantity variance

Materials price variance = AQ (AP - SP)

= 19,250 ($1.70 - $1.60)

= $1,925 unfavorable

Materials quantity variance = SP (AQ - SQ)

= $1.60 (19,250 - (2,500 × 8))

= $1,200 favorable

2. Calculation of Labor rate variance and labor efficiency variance

Labor rate variance = AH (AR - SR)

= 400 ($13.00 - $13.00)

= $0 None

Labor efficiency variance = SR (AH - SH)

= $13.00 (400 - (2,500 × 0.16))

= $2,080 unfavorable

Direct Materials Price variance measures the effect of differences between actual and expected material prices, while Direct Materials Quantity variance measures the effect of differences between actual and expected quantities of materials.

Direct Labor Rate variance measures the effect of differences between actual and expected labor rates, while Direct Labor Efficiency variance measures the effect of differences between actual and expected labor productivity.

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Answer: it is group1 or group 3 on god

Explanation:

The pressure of the nitrogen gas would need to decrease to 3.94 atm in order for the volume to increase to 10.90 L, assuming constant temperature and ideal behavior.

To solve this problem, we can use the ideal gas law equation: PV = nRT, where P is pressure, V is volume, n is the number of moles of gas, R is the gas constant, and T is the temperature.

Since the temperature is constant, we can simplify the equation to P1V1 = P2V2. We know that the initial pressure (P1) is 5.06 atm and the initial volume (V1) is 8.52 L.

We want to find the final pressure (P2) when the volume (V2) is 10.90 L. Plugging these values into the equation, we get (5.06 atm)(8.52 L) = P2(10.90 L). Solving for P2, we get P2 = (5.06 atm)(8.52 L) / (10.90 L) = 3.94 atm.

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Answer:

please mark as brainliest

Explanation:

Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons . The difference in the number of neutrons between the various isotopes of an element means that the various isotopes have different masses.

example:chlorine is an example of an isotope it has a proton number of 17 and a mass number of 35 in some cases they have a proton number of 17 and a mass number of 37 there is difference in the number of neutron to calculate this we do it this way.for the first one

mass number=proton+neutron

neutron=mass number-proton

neutron=35-17

neutron=18

for the second one

neutron=37-17

neutron=20

Answer:

Gravity

Explanation:

According to Newton's Law of Gravity, an object with mass will attract another object with mass.

Answer:

The coefficient for Al(s) is 2.

Explanation:

__ Al(s) __ O2(g) --> __ Al2O3(s)

__ Al(s) __ O2(g) --> 1 Al2O3(s)

1 Al(s) __ O2(g) --> 1 Al2O3(s)

1 Al(s) + 1.5 O2(g) --> 1 Al2O3(s)             [Use a fraction to make it balance]

2 Al(s) + 3 O2(g) --> 2 Al2O3(s)             [Convert the 1.5 fraction to a whole number by multiplying all coefficients by 2]

Answer:

It's basically an active site of an enzyme precisely fits a specific substrate. It reduces the energy that is well needed for reactants that come together.

Answer:

Your answer would be "Polyatomic anions."

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Reaction of 7.5 g of sodium carbonate with a dilute solution of hydrochloric acid (HCl) gives a mass of 8.28 g of NaCl.

1 mole of sodium carbonate yields 2 moles of sodium chloride.

To find grams and volume, we need to calculate the molecular mass of the reactants and products.

So the molecular mass will be:

Na2Co3=106

2 NaCl = 117

160 g Na2Co3 = 117 g NaCl (1)

7.5 g Na2Co3 gives = 'X' g NaCl (2)

Cross-multiplying equations 1 and 2 gives:

X × 106 = 117 × 7.5

X = 8.28

Diploma:

From this we conclude that 7.5 g of sodium carbonate reacts with a dilute solution of hydrochloric acid (HCl) to yield 8.28 g of mass NaCl.

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Maintaining appropriate fluid levels All of these, excluding caloric balance, are necessary for homeostasis. Normal fluid homeostasis is the control of the body's water and electrolyte balance. Homeostasis is the preservation of a stable internal environment within the body.

In order for the body's organs and tissues to operate effectively, the right amounts of water, electrolytes, and acid-base balance must be maintained. Since caloric balance has no direct impact on the body's levels of water and electrolytes, it is not a role in normal fluid homeostasis.

Instead, caloric balance refers to how much energy is being absorbed and used, and it has an impact on how well the body can control its temperature. Therefore, appropriate fluid homeostasis can occur without caloric balance.

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Answer:

wd

Explanation:

h

Answer:

i hope it will help you ..

The name of pb(no3)2 is Lead(II) nitrate.

pb(no3)2 is an ionic compound.

How to name ionic compound?

Name of pb(no3)2:

The charge of nitrate ion NO3 is -1. To find the charge of lead, we'll take it as x. Hence,

x+2(-1)=0

x=2

The charge of lead cation in this ionic compound is calculated as +2.

Therefore the name of pb(no3)2 is confirmed as Lead(II) Nitrate.

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A construction worker spilled a bag of powdered chemical, covering both of his arms . he complains of intense pain ,then in that case , the patient who was exposed to a powdered chemical , it is important to brush the chemical from the skin first ,then irrigate the site with copious ( abundant ,extensive in quantity ) amount of water .

Due to the cleaning of chemical from the hand , it minimize the risk to the hand by removing the extra amount of chemical from the surface and helps in rapid cure .

chemical exposure to the skin can cause temporary or permanent health damage .temporary skin damage may occur from exposure to chemicals. for example ,many workers may experience dry ,red ,cracked skin from contact with water ,soaps ,gasoline and certain types of solvents .

Permanent skin damage may occurs if the skin is exposed to a chemical that is known to have a severe impact . exposure to certain chemicals can results permanent loss of skin color .permanent damage may occurs to certain organs also like exposure to certain solvents may results in the permanent loss of skin color .

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Oxygen can only generate two bonds because it needs two additional electrons to complete its octet, after which it will run out of empty orbitals in which to receive additional electrons and create additional bonds.

These compounds have four, three, two, and one bonds between the carbon, nitrogen, oxygen, and chlorine atoms, respectively.

Oxygen typically contains two bonds, but it can also have three. If it has three bonds, it will be positively charged. An oxygen atom frequently has just one link, although the atom is negatively charged. Halogens typically only have one bond; polyatomic ions are significant exceptions.

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To produce 35.5g of H2, approximately 2055.49g of NaCl is required.

To calculate the mass of NaCl required to produce 35.5g of H2, we need to determine the stoichiometry of the reaction and use the molar mass of NaCl.

The balanced equation for the reaction is:

2NaCl + 2H2O -> 2NaOH + H2

From the balanced equation, we can see that for every 2 moles of NaCl, 1 mole of H2 is produced. We can use the molar mass of H2 (2.016g/mol) to convert the given mass of H2 into moles:

moles of H2 = mass of H2 / molar mass of H2

moles of H2 = 35.5g / 2.016g/mol

moles of H2 = 17.6 mol

Since the stoichiometry of the reaction is 2 moles of NaCl to 1 mole of H2, we can set up the following ratio:

moles of NaCl / moles of H2 = 2 / 1

Rearranging the equation to solve for moles of NaCl:

moles of NaCl = (moles of H2 * 2) / 1

moles of NaCl = (17.6 mol * 2) / 1

moles of NaCl = 35.2 mol

Now, we can calculate the mass of NaCl required using the molar mass of NaCl (58.44g/mol):

mass of NaCl = moles of NaCl * molar mass of NaCl

mass of NaCl = 35.2 mol * 58.44g/mol

mass of NaCl = 2055.49g

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The Avogadro's number is the constant number for the number of atoms or molecules represented in 1 mol, this number is equal to 6.022*10^23, to find out how many molecules there are in 6.0 moles we can set up this equation:

6.0 moles of CH4 * 6.022*10^23 molecules / 1 mol of CH4

The answer will be 3.61*10^24 molecules of CH4

The step(s) that compose rationale for the cation Ag+ being absent in an unknown (but Pb+2 is present) are:

Step 1 involves adding KCl and HCl to the unknown solution, which should result in the formation of white precipitates of AgCl and PbCl2 if Ag+ and Pb+2 are present.

The absence of a white precipitate in step 1-A suggests that Ag+ may not be present, and this is supported by the fact that the precipitate dissolves in hot water, indicating it is not AgCl, which is insoluble in water.

In step 1-B, the addition of H2S produces a black precipitate of PbS, indicating the presence of Pb+2. The absence of a black precipitate in step 1-B also suggests that Ag+ may not be present.

Step 1-C involves adding K2CrO4 to the unknown solution to test for the presence of Pb+2, which should result in the formation of a yellow precipitate of PbCrO4. The absence of a yellow precipitate indicates that Pb+2 may not be present.

Step 2-B involves adding NH3 to the unknown solution, which should result in the formation of a dark blue solution if Ag+ is present. The absence of a dark blue color suggests that Ag+ may not be present.

The remaining steps (4, 5, 6, 7) involve the use of additional reagents to further differentiate between Ag+ and Pb+2. For example, the addition of KFe(CN)6 to the unknown solution should result in the formation of a reddish-brown precipitate if Ag+ is present, but not if Pb+2 is present.

Overall, by observing the results of these specific reactions with various reagents, it is possible to determine the presence or absence of specific cations in the unknown solution. In this case, the results suggest that Pb+2 is present, but Ag+ is not.

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Answer:

Answer Option A) To attain a noble-gas electron configuration.

Explanation:

Correct answer from test

Taking into account the definition of covalent bond and octet rule, the correct answer is option A.  Atoms share electrons in covalent bonds to achieve a noble gas electron configuration.

The covalent bond is the chemical bond that occurs between atoms of non-metallic elements. These atoms have many electrons at their outermost level and have a tendency to share them to acquire the stability of the noble gas electronic structure. In this way a molecule is formed.

The tendency of the elements to reach a stable configuration is known as the octet rule. For this, the octet rule explains that there must be eight electrons in their last energy levels, thus acquiring the structure of a noble gas.

So, a covalent bond is a force that joins two atoms of non-metallic elements to form a molecule in order to comply with the octet rule.

Finally, the correct answer is option A.  Atoms share electrons in covalent bonds to achieve a noble gas electron configuration.

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In order to do this, particles were created by combining equal amounts of calcium chloride (CaCl2) and sodium carbonate (Na2CO3), with the initial salt concentrations of CaCl2 and Na2CO3 ranging from 5 10-4 to 5 10-2 M.

Calcium carbonate is utilized as a dietary supplement when the calcium intake from food alone is insufficient. For healthy bones, muscles, a neurologic system, and a heart, the body needs calcium. Calcium carbonate is also used as an antacid to treat heartburn, acid reflux, and stomach pain. Calcium carbonate has the chemical formula CaCO3. It is a chemical that frequently occurs in rocks as that of the minerals calcite & aragonite and is used as the main component of pearl, gastropod shell, eggshells, and the skeletons of shellfish. Calcareous refers to things with a high concentration of calcium carbonate or things that resemble it.

High levels of calcium in your blood might cause swelling, rapid weight gain, or symptoms like nausea, vomiting, constipation, increased thirst or urination, muscular weakness, bone pain, confusion, a lack of energy, or feeling exhausted.

Effects on Humans: Humans' eyes, noses, mucous membranes, and skin are all physically irritated by calcium carbonate dust. When calcium carbonate dust comes into contact with the eyes, it produces swelling, soreness, and redness of the eyelids, whereas when it comes into contact with the skin, it causes mild local irritation.

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The substances that participate in a reaction are called reactants, whereas the substance that forms as a result of a reaction is called a product.

Reactants are the starting materials that are involved in a chemical reaction, which undergo a transformation to form new substances. The reactants are typically shown on the left side of a chemical equation, with an arrow pointing to the right side, where the products are shown.

Products, on the other hand, are the new substances that are formed as a result of the chemical reaction. They are typically shown on the right side of a chemical equation, with an arrow pointing from the reactants on the left side.

Chemical reactions involve the breaking and formation of chemical bonds, which result in the rearrangement of atoms to form new substances with different chemical and physical properties than the reactants. The law of conservation of mass dictates that the total mass of the reactants must be equal to the total mass of the products in a chemical reaction.

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Alcohols can be oxidized to form aldehydes using reagents such as PCC (pyridinium chlorochromate), Dess-Martin periodinane, or chromic acid (H₂CrO₄).

Alcohols can undergo oxidation reactions to produce aldehydes using various reagents. One commonly used reagent is PCC (pyridinium chlorochromate), which selectively oxidizes primary alcohols to aldehydes without further oxidation to carboxylic acids. PCC is a mild and versatile oxidizing agent that is widely employed in organic synthesis.

Another reagent is Dess-Martin periodinane, which is a highly efficient and selective oxidizing agent for the conversion of primary and secondary alcohols to aldehydes and ketones, respectively. It provides a convenient and mild method for the preparation of aldehydes.

Chromic acid (H₂CrO₄) is also used as an oxidizing agent to convert primary alcohols to aldehydes. However, chromic acid is a stronger oxidizing agent compared to PCC and Dess-Martin periodinane and can further oxidize aldehydes to carboxylic acids if reaction conditions are not carefully controlled.

These oxidizing agents provide useful tools for the synthesis of aldehydes from alcohols in organic chemistry.

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Answer:

opción c es la respuesta correcta espero que te ayude

Explanation:

Homologous series are the series belonging to a series of aliphatic organic compounds that differ only by the addition of a CH2 group

Hope it will help :)❤

a) The concentration of the HCl solution is 0.1 M.

b) The concentration of the H₂SO₄ solution is 0.1872 M.

a) To solve both of these problems, we can use the formula M₁V₁ = M₂V₂, where M₁ is the concentration of the first solution, V₁ is the volume of the first solution used, M₂ is the concentration of the second solution, and V₂ is the volume of the second solution used.

For the first problem, we are given that 40 mL of a 0.25 M NaOH solution neutralizes 100 mL of an HCl solution. We can use the formula to solve for the concentration of the HCl solution:

0.25 M x 40 mL = M₂ x 100 mL

M₂ = (0.25 M x 40 mL) / 100 mL

M₂ = 0.1 M

b) For the second problem, we are given that 72 mL of a 0.65 M NaOH solution neutralizes 125 mL of an H₂SO₄ solution. However, H₂SO₄ is a diprotic acid, meaning that it can donate two hydrogen ions (H⁺) per molecule.

Therefore, we need to account for this when calculating the concentration of the H₂SO₄ solution:

0.65 M x 72 mL = 2 x M₂ x 125 mL

M₂ = (0.65 M x 72 mL) / (2 x 125 mL)

M₂ = 0.1872 M

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