a random sample of 81 credit card sales showed a sample standard deviation of $55. a 90onfidence interval estimate of the population variance is

Wind and Erosion lead to Washing away of top soil.

Erosion is the process that lead to the washing away of top soil leading to loss of nutrient, holes and many more.

The agents of erosion include wind, water and so on.

Strong wind will lead to the top soil to be remove when it is blowing. Water also when is is flowing turbulently maybe when rain fall can lead to loss of top soil.

Therefore, Wind and Erosion lead to Washing away of top soil.

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The completed sentence contains as follows

In the first step of the Krebs cycle, pyruvate dehydrogenase condenses with oxalo-cyclate , a 4 carbon compound. It forms citrate with removal of CoA. Citrate which thus formed has 3 carboxylic acid group and hence this cycle is called TCA cycle or Tricarboxylic acid cycle.

In reaction 2, this citrate thus formed undergoes isomerization to form isocitrate. The enzyme used in the reaction is called aconitase because this isomerization happens with cis-aconitate as the intermediate.

Further, in the reaction 3, CO₂ is eliminated to form \alpha -ketoglutarate which is a 5 carbon containing carboxylic acid. Here, oxidation occurs by electron transfer to NAD⁺ which is converted from NADH.

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Since E° is positive 2.64 V, ΔG° will be negative, indicating that the reaction is spontaneous.

To predict the sign for ΔG°, we can use the formula:

ΔG° = -nFE°

where n is the number of electrons transferred in the reaction, F is the Faraday constant (96485 C/mol), and E° is the standard cell potential.

From the balanced equation for the overall reaction, we can see that two electrons are transferred, so n = 2. The value of E° can be calculated using the standard reduction potentials for the cathode and anode half-reactions:

E°cell = E°cathode - E°anode

E°cell = -0.23 V - (-2.87 V)

E°cell = 2.64 V

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Answer:

Counting the number of colonies that arise on a pour plate can calculate the concentration by multiplying the count by the volume spread on the pour plate. Direct counting methods are easy to perform and do not require highly specialized equipment, but are often slower than other methods

Explanation:

I hope it will help you

Answer:

2.0 liters of oxygen gas.

Explanation:

To determine the volume of oxygen gas required to completely combust a given amount of propane, we need to know the chemical equation for the combustion of propane. The combustion of propane can be represented by the following equation:

Propane + Oxygen → Carbon Dioxide + Water

According to the balanced chemical equation, it takes two molecules of oxygen gas to completely combust one molecule of propane. Therefore, to completely combust 1.0 liters of propane at standard temperature and pressure (STP), we would need 2.0 liters of oxygen gas.

The Lewis structure of the compound is octet rule.

According to the octet rule, the stability of an atom is determined by the fact that there are eight electrons that surround the the outermost shell of the atom.

Now we can see that we are to draw the Lewis structure of the compound silicon disulfide. In this compound,  each of the atoms must obey the octet rule and meaning of this is that they would have eight electrons that surround the valence shell.

We can see that there are multiple bond in the compound.

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Answer:

See the answer below

Explanation:

When silver is added to dilute sulphuric acid, no reaction would occur. However, silver reacts with hot and concentrated sulphuric acid to produce silver sulphate, sulphur dioxide, and water.

The equation of the reaction is as below:

silver + sulphuric acid --> silver sulphate + water + sulphur dioxide

\(2Ag(s) + 2 H_2SO_4(aq) -->Ag_2SO_4 (s) + 2 H_2O (l) + SO_2 (aq)\)

Compound X is a reversible inhibitor of the enzyme, Enzyme samples were passed through a procedure to remove small molecules and then measured for carbon-14 label content.

Once an enzyme has catalysed a reaction and has been released from its binding to a substrate, it can be used for other reactions.

The enzyme, which is now free and ready to catalyse the conversion of a further molecule of substrate into a product, has undergone absolutely no change.

As a catalyst, it is important to remember that the enzyme is not permanently altered by the reaction; rather, the enzyme returns to its initial state after the reaction has finished.

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A purified enzyme was incubated with the various concentrations of the low-molecular-weight carbon-14 labeled Compound X, the conclusion drawn is the compound X is the reversible inhibitor of enzyme.

The reversible inhibitor of the enzyme is the one, that will once removed and allow the enzyme and it will inhibiting to start the working again. this will not effect the enzyme permanently. the enzyme is now ready for the conversion of the molecule of the substrate to the product.

The three types of the reversible inhibitor is : the competitive inhibitor , the non competitive inhibitor and the uncompetitive inhibitor.

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The concentration of the [CoCl₄]²⁻ complex with an absorbance value of 0.88 (assuming l = 1 cm) is approximately 0.001524 M.

The Beer-Lambert Law is given by the equation:

A = εcl

Absorbance (A) = 0.88

Molar absorptivity (ε) = 577.2 m⁻¹cm⁻¹

Path length (l) = 1 cm

c = A / (εl)

c = 0.88 / (577.2 m⁻¹cm⁻¹ * 1 cm)

c = 0.88 / 577.2 m⁻¹

c ≈ 0.001524 M

Therefore, the concentration of the [CoCl₄]²⁻ complex with an absorbance value of 0.88 (assuming l = 1 cm) is approximately 0.001524 M.

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The advantage of making a solvent unblocking lightly nonpolar is to increase the solubility of polar and ionic compounds.

The solubility of a solute in a solvent is largely determined by the relative polarity of the solute and solvent. Polar solvents dissolve polar solutes, while nonpolar solvents dissolve nonpolar solutes. Making a solvent unblock lightly nonpolar increases its ability to dissolve polar and ionic compounds by reducing the difference in polarity between the solvent and solute.

This allows polar and ionic compounds to be dissolved in a nonpolar solvent, which can be useful in various applications, such as chromatography and chemical reactions.

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Answer:

B

Explanation:

Just by looking at the amount of carbons on the straight chain which is four and whom prefix is butane we can see that B is the answers

Answer:

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Answer:

An adaptation occurs if a mutation helps an individual survive and reproduce.

Explanation:

Over generations, the mutation will become more common. An adaptation occurs if a mutation isn't passed on to offspring. Hope this helps! xx

Answer:

\( \sf \: correct \: answer \: would \: be \: methanol!\)

Explanation:

Specific Heat: The specific Heat of any material is the heat absorbed or evolved by the material to raise or fall it's temperature by 1°C per unit mass of the material.

The heat absorbed or evolved (Q) is directly proportional to the mass of substance(m) and rise or fall of temp(∆T)

The general formula for specific heat is,

\(\sf \: \: \: \: \: s = \frac{Q}{m\Delta T}\)

Where

Now coming to your question,

The specific heat of Aluminium is 897 J/kg °C

The specific heat of Aluminium is 897 J/kg °C& specific heat of methanol is 2450 J/kg ° C

The definition states that, if the specific heat would be more, more amount of heat will be required for per unit change in temperature.

The specific heat of Aluminium is 897 J/kg °C which means for one kilogram aluminium, 897 Joule energy is required to change it's temperature by 1°C & Similarly for one kilogram methanol 2450 joule energy is required.

Hence, the correct answer would be methanol!

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\(\small \sf \: Thanks \: for \: joining \: brainly \: community!\)

Answer:

3.6 meters

Explanation:

The wavelength of a water wave is the distance between two successive peaks or troughs of the wave.

To find the wavelength of the water waves in the lake, we can use the formula:

wavelength = speed / frequency

where speed is the speed of the wave and frequency is the number of cycles (peaks or troughs) that pass a fixed point in a given time period. The frequency of a wave is related to its period, which is the time it takes for one complete cycle (peak or trough) to pass a fixed point. The frequency of a wave is the reciprocal of its period, so we can rewrite the formula as:

wavelength = speed / (1 / period)

Plugging in the values from the problem, we get:

wavelength = 4.4 meters / (1 / 1.2 seconds)

wavelength = 4.4 meters / (1.2 seconds)

wavelength = 3.6 meters

So the wavelength of the water waves in the lake is 3.6 meters.

Water waves in a lake travel 4.4 meters in 1.8 s. The period of oscillation is 1.2 s. 3.6 meters is their wavelength.

The wavelength of a water wave is the spatial arrangement between two successive peaks or troughs of the wave.

To find the wavelength of the water waves in the lake,  use the formula:

Wavelength = speed/frequency

Where speed is the speed of the wave and frequency is the number of cycles that pass a fixed point in a given time period.

The frequency of a wave is related to its period, which is the time it takes for one complete cycle to pass a fixed point. The frequency of a wave is the reciprocal of its period, the formula is given as:

wavelength = speed / (1 / period)

Substitute the values from the given information, we get:

wavelength = 4.4 meters / (1 / 1.2 seconds)

wavelength = 4.4 meters / (1.2 seconds)

wavelength = 3.6 meters

Thus,  the wavelength of the water waves in the lake is 3.6 meters.

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This is the fundamental redox reaction between Br2 and SO32- :

Br2 + SO32- + H2O= 2Br- + SO42- + 2OH-

A chemical process known as a redox reaction, also known as a reduction-oxidation reaction, includes the exchange of electrons between the reactants. It combines two distinct reactions: an oxidation reaction, in which an atom or molecule loses electrons, and a reduction reaction (where a molecule or atom loses electrons).

In this reaction, SO32- is oxidized to SO42- while Br2 is reduced to Br-. Br2 gains the electrons that SO32- loses, converting the reaction into a redox one. The reaction takes place in a basic solution, and the hydrogens and charges need to be balanced by the addition of hydroxide ions (OH-). The balanced equation demonstrates that two molecules of Br-, one molecule of SO42-, and two molecules of OH- are the results, and that one molecule of SO32- is needed for every one molecule of Br2.

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The fact that the amount of substances is fundamental means that its unit, the mole should be a base unit.

We have to know that the SI unit is the internationally accepted unit that we can be able to use to obtain the quantities that are basic in physics. We know that there are some units that we call the base units.

The reason why we call them the base units is because all other computations are based on them. The mole should be a base unit because the mole deals with the amount of substance which is quite fundamental in science.

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The correct answer is A. Based on the given options, amino acids can be classified into different categories based on the properties of their R groups.

it are organic compounds serve as the building blocks of proteins. They consist of a central carbon atom (alpha carbon) bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and an R group (side chain) that varies among different amino acids.

classified R groups amino acids. The given options represent different classifications:

A. Hydrophobic amino acids with nonpolar R groups: These amino acids have R groups that are nonpolar and do not readily interact with water molecules. They tend to be hydrophobic (water-fearing) and are often found in the interior of proteins away from water.

B. Polar amino acids with neutral R groups but the charge is not evenly distributed: These amino acids have polar R groups that contain functional groups such as hydroxyl (-OH) or amine (-NH2). Although they are polar, the charge is not evenly distributed within the R group.

C. Positively charged amino acids with R groups that have positive charge at physiological pH: These amino acids have R groups that contain positively charged functional groups, such as amino groups (-NH3+), at physiological pH (around 7.4).

D. Negatively charged amino acids with R groups that have a negative charge at physiological pH: These amino acids have R groups that contain negatively charged functional groups, such as carboxylate groups (-COO-), at physiological pH.

Based on the given options, amino acids can be classified into different categories based on the properties of their R groups. Amino acids with hydrophobic nonpolar R groups are classified as hydrophobic amino acids.

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Answer:

Explanation:

Here, we want to calculate the initial volume of the container

Mathematically, we know that volume and pressure are inversely related. What this means is that as volume increases, pressure is expected to decrease and as pressure increases, volume is expected to decrease

A mathematical link between these two is as follows:

The above is according to Boyles' law.

The values with subscript 1 are the initial values, while the values with the subscript 2 are the final values

Thus:

V1 = ?

P1 = 1.25 atm

V2 = 1L

P2 = 3.75 atm

From the relation:

There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, chemical formula can be shown as below.

Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.

An ionic compound is a metal and nonmetal combined compound.  Ionic compound are very hard. They have high melting and boiling point because of strong ion bond.

Compound                                                          chemical formula

alkane                                                                  CnH2n+2

alkene with one double bond                            CH\(_2\)=CH\(_2\)

alkene with two double bond                             CH\(_2\)=c=CH\(_2\)

cycloalkane                                                          C\(_6\)H\(_{12}\)

Therefore, chemical formula can be shown as above.

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1.73 minutes are required to deposit 2.61 g cr from a cr³⁺(aq) solution using a current of 2.50 a

Electroplating is a process of depositing a metal onto a conductive surface by using electrolysis. In this process, an electric current is passed through an electrolyte solution containing ions of the metal to be deposited. The metal ions are reduced at the cathode, which is the surface where the metal is being deposited. The rate at which the metal is deposited depends on the current and the time for which the current is applied.

To calculate the time required to deposit a certain amount of metal, we can use Faraday's law of electrolysis, which states that the amount of metal deposited is proportional to the amount of electric charge that passes through the cell. The equation for this is:

mass of metal deposited = (current x time x atomic mass of metal) / (Faraday's constant x charge on ion)

In this problem, we are given the current (2.50 A), the mass of metal to be deposited (2.61 g), the charge on the Cr³⁺ ion (3+), and the Faraday's constant (96,500 C/mol). The atomic mass of Cr is 52.0 g/mol.

Substituting these values into the equation, we get:

2.61 g = (2.50 A x time x 52.0 g/mol) / (96,500 C/mol x 3)

Simplifying this equation gives:

time = (2.61 g x 96,500 C/mol x 3) / (2.50 A x 52.0 g/mol)

time = 103.9 s or 1.73 minutes (rounded to two decimal places)

Therefore, it would take approximately 1.73 minutes to deposit 2.61 g of Cr from a Cr³⁺(aq) solution using a current of 2.50 A.

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The density of dinitrogen monoxide gas at exactly 20 °C and exactly 1 atm is 1.83 g/L.

The problem states that we can treat this gas as an ideal gas, therefore, we can use the equation of an ideal gas which is:

PV = nRT

Now, the density (d) is calculated as:

d = m/V

We can rewrite above equation,

m = d*V

Now, the moles (n),

n = m /MM

The ideal gas equation is,

d = P * MM / RT

The molar mass of N₂O is 44 g/mol.

So, replacing all the data we have:

\(d = \dfrac{1 \times 44}{0.082 \times 293}\)

d = 1.83 g/L

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The standard enthalpy change for reaction (3) is 117.1 kJ.

The standard enthalpy change for reaction (3) can be calculated by using the enthalpy changes of reactions (1) and (2) and applying Hess's Law.

To do this, we need to manipulate the given equations so that the desired reaction (3) can be obtained.

First, we reverse reaction (1) to get the formation of C2H4(g) from C2H6(g):

C2H4(g)C2H6(g) ΔH° = -52.3 kJ

Next, we multiply reaction (2) by 2 and reverse it to obtain 2 moles of C2H6(g) reacting to form 3 moles of H2(g):

2C2H6(g)2C(s) + 3H2(g) ΔH° = 169.4 kJ

Now, we add the two modified equations together:

C2H4(g)C2H6(g) ΔH° = -52.3 kJ
2C2H6(g)2C(s) + 3H2(g) ΔH° = 169.4 kJ

When adding these equations, the C2H6(g) on the left side cancels out with the C2H6(g) on the right side, leaving us with the desired reaction (3):

C2H4(g) + H2(g)C2H6(g) ΔH° = -52.3 kJ + 169.4 kJ = 117.1 kJ

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In the preceding equation, 6.67 moles of boric acid (\(H_3BO_3\)) will react to generate 10 moles of water (\(H_2O\)).

To determine the number of moles of boric acid that react in the equation to produce 10 moles of water, we need to examine the balanced chemical equation and use stoichiometry.

1. Begin by examining the balanced chemical equation for the reaction involving boric acid and water. Let's assume the equation is:

  \(3H_2O\) + \(3H_2O\) -> \(B_2O_3\) + \(6H_2O\)

2. From the balanced equation, we can see that 2 moles of boric acid (H3BO3) react with 3 moles of water (\(H_2O\)) to produce 6 moles of water (\(H_2O\)).

3. Use the given information that 10 moles of water (\(H_2O\)) are produced. Since the stoichiometric ratio between boric acid and water is 2:3, we can set up a proportion to find the number of moles of boric acid:

  2 moles \(H_3BO_3\) / 3 moles \(H_2O\) = x moles \(H_3BO_3\) / 10 moles \(H_2O\)

4. Cross-multiply and solve for x:

  (2 moles \(H_3BO_3\))(10 moles \(H_2O\)) = (3 moles \(H_2O\))(x moles \(H_3BO_3\))

  20 moles \(H_2O\) = 3x moles \(H_3BO_3\)

5. Divide both sides of the equation by 3 to isolate x:

  x moles \(H_3BO_3\) = (20 moles \(H_2O\)) / 3

6. Calculate the value of x:

  x moles \(H_3BO_3\) ≈ 6.67 moles \(H_3BO_3\)

Therefore, approximately 6.67 moles of boric acid (\(H_3BO_3\)) will react to produce 10 moles of water (\(H_2O\)) in the given equation.

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The ratio of atoms determines the empirical formula of adipic acid. As a result, C₂H₂O is the empirical formula for adipic acid.

To determine the empirical formula of adipic acid based on the given percentages of carbon (C), oxygen (O), and hydrogen (H) by mass, we need to convert these percentages into moles and then find the simplest whole number ratio.

Assume we have 100 grams of adipic acid. This assumption allows us to directly convert the percentages into grams.

Mass of C = 49.32 g

Mass of O = 43.84 g

Mass of H = 6.85 g

Convert the masses of each element into moles by dividing by their respective molar masses:

Molar mass of C = 12.01 g/mol

Molar mass of O = 16.00 g/mol

Molar mass of H = 1.01 g/mol

\(\text{Moles of C} = \frac{{49.32 \, \text{g}}}{{12.01 \, \text{g/mol}}} \approx 4.107 \, \text{mol}\)

\(\text{Moles of O} = \frac{{43.84 \, \text{g}}}{{16.00 \, \text{g/mol}}} \approx 2.740 \, \text{mol}\)

\(\text{Moles of H} = \frac{{6.85 \, \text{g}}}{{1.01 \, \text{g/mol}}} \approx 6.792 \, \text{mol}\)

Determine the simplest whole number ratio of the moles by dividing each mole value by the smallest mole value:

\(\text{Moles of C} = \frac{{49.32 \, \text{g}}}{{12.01 \, \text{g/mol}}} \approx 4.107 \, \text{mol}\)

\(\text{Moles of O} = \frac{{43.84 \, \text{g}}}{{16.00 \, \text{g/mol}}} \approx 2.740 \, \text{mol}\)

\(\text{Moles of H} = \frac{{6.85 \, \text{g}}}{{1.01 \, \text{g/mol}}} \approx 6.792 \, \text{mol}\)

Round the mole ratios to the nearest whole number:

Moles of C ≈ 2

Moles of O ≈ 1

Moles of H ≈ 2

The empirical formula of adipic acid is determined by the ratio of atoms. Therefore, the empirical formula of adipic acid is C₂H₂O.

Note: The molecular formula of adipic acid may be a multiple of the empirical formula, indicating a higher number of atoms in the actual molecule.

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The equilibrium vapor pressure with respect to water (eow) is 259.9 Pa. assume that saturation vapor pressure is same as equilibrium vapor pressure.

Therefore, the RH at the frost point is  

RH = (eow / saturation vapor pressure) × 100

= (259.9 Pa / 259.9 Pa) × 100

= 100%

b) At T = -11 °C, we need to compare the equilibrium vapor pressure with respect to water (eow) and the equilibrium vapor pressure with respect to ice (coi) to determine if ice particles will form. From the given table, at T = -11 °C, the equilibrium vapor pressure with respect to water (eow) is 237.7 Pa, and the equilibrium vapor pressure with respect to ice (coi) is 165.3 Pa.

The air is supersaturated with respect to ice, and the presence of Kaolinite particles can provide surfaces for water droplets to condense onto, leading to the formation of ice particles.

c) At T = -12 °C, we compare the equilibrium vapor pressure with respect to water (eow) and the equilibrium vapor pressure with respect to ice (coi). From the given table, at T = -12 °C, the equilibrium vapor pressure with respect to water (eow) is 217.3 Pa, and the equilibrium vapor pressure with respect to ice (coi) is 181.2 Pa.

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Answer:

Y

ou have learnt in your previous classes that the sour and bitter

tastes of food are due to acids and bases, respectively, present in them.

If someone in the family is suffering from a problem of acidity after

overeating, which of the following would you suggest as a remedy– lemon

juice, vinegar or baking soda solution?

n Which property did you think of while choosing the remedy?

Surely you must have used your knowledge about the ability of

acids and bases to nullify each other’s effect.

n Recall how we tested sour and bitter substances without tasting

them.

You already know that acids are sour in taste and change the colour

of blue litmus to red, whereas, bases are bitter and change the colour of

the red litmus to blue. Litmus is a natural indicator, turmeric is another

such indicator. Have you noticed that a stain of curry on a white cloth

becomes reddish-brown when soap, which is basic in nature, is scrubbed

on it? It turns yellow again when the cloth is washed with plenty of

water. You can also use synthetic indicators such as methyl orange and

phenolphthalein to test for acids and bases.

In this Chapter, we will study the reactions of acids and bases, how

acids and bases cancel out each other’s effects and many more interesting

things that we use and see in our day-to-day life. Do You Know?

Litmus solution is a purple dye, which is extracted from lichen, a plant belonging to

the division Thallophyta, and is commonly used as an indicator. When the litmus

solution is neither acidic nor basic, its colour is purple. There are many other natural

materials like red cabbage leaves, turmeric, coloured petals of some flowers such as

Hydrangea, Petunia and Geranium, which indicate the presence of acid or base in a

solution. These are called acid-base indicators or sometimes simply indicators.

2021–22

18 Science

2.1 UNDERSTANDING THE CHEMICAL PROPERTIES OF

ACIDS AND BASES

2.1.1 Acids and Bases in the Laboratory

Activity 2.1

These indicators tell us whether a substance is acidic or basic by

change in colour. There are some substances whose odour changes in

acidic or basic media. These are called olfactory indicators. Let us try

out some of these indicators.

Explanation:

Answer:

Consumers are unable to make their own energy, and instead rely on the consumption and digestion of producers or other consumers, or both, to survive.

Decomposer is an organism, especially a soil bacterium, fungus, or invertebrate, that decomposes organic material. They are all living things that get energy by eating dead animals and plants and breaking down wastes of other animals.

Explanation:

Answer:

A

Explanation:

Density is the ratio of mass to volume. The substance with the lowest density has the largest volume. The volume of magnesium will be the largest.

Density is the mass per volume of the substance. It is denoted by the Latin letter rho (ρ) or D. It is the division of the mass in kilograms to the volume in cubic meters.

The relation of the density is inversely proportional to the volume and when the order is given in increasing order of density then magnesium will have the largest volume as it has the least density.

Therefore, magnesium has the largest volume.

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