a certain substance has a normal boiling point of and a molal boiling point elevation constant . a solution is prepared by dissolving some urea in of . this solution boils at . calculate the mass of urea that was dissolved. round your answer to significant digits.

Answer:

CFLs (compact fluorescent lights) contain small amounts of mercury, a toxic heavy metal. If a CFL bulb breaks, the mercury can be released into the environment, where it can contaminate water and soil, and harm wildlife and human health. This is considered one of the major environmental issues associated with CFLs.

The boiling point of the solution made by dissolving 9.70 g of naphthalene in 90.7 g of benzene is 139.3 °C.

The boiling point of a solution is elevated compared to the boiling point of the pure solvent, due to the presence of solute particles in the solution. The boiling point elevation can be calculated using the following equation:

ΔT = Kb x molality

where ΔT is the change in boiling point, Kb is the boiling point elevation constant, and molality (m) is the concentration of the solute expressed in mol/kg.

To use this equation, we first need to find the molality of the naphthalene in the solution. To do this, we need to find the number of moles of naphthalene in the 9.70 g sample:

9.70 g naphthalene / 128.17 g/mol

=> 0.0758 mol naphthalene

Next, we need to find the mass of the solvent in the solution, which is 90.7 g. The molality of the naphthalene can then be calculated as follows:

molality = moles solute / mass of solvent (in kg)

=> 0.0758 mol / (90.7 g / 1000 g/kg)

=> 0.0837 mol/kg

Now that we have the molality, we can calculate the boiling point elevation:

ΔT = Kb x molality

=> 2.53 K/m x 0.0837 mol/kg

=> 0.2111 K

Finally, we can use the boiling point elevation to find the boiling point of the solution:

Boiling point of solution = boiling point of solvent + ΔT

=> 80.1 °C + (0.2111 K x 273.15)

=> 80.1 + 59.18

=> 139.3 °C

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The stated statement states that 398 mg of Krypton contains 4.75 x 10-3 moles of Kr.

Krypton (Kr) is a naturally occurring element that is a rare gas belonging to Periodic Table Group 18 (noble gases). It only forms a small number of chemical compounds. Krypton is monoatomic, tasteless, colorless, and about 3.5 times heavier than air.

Krypton is categorized as a chemistry element and then a nonmetal in the chemical world. William Gordon and his helper Morris Travers found it in 1898.

The molar mass of Kr is 83.80 g/mol.

So, moles = 398 mg / 1000 mg/g / 83.80 g/mol = 4.75 x [tex]10^{-3}[/tex] moles Kr

So, the answer is a. 4.75 x [tex]10^{-3}[/tex] moles Kr.

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We have to use Greek numerals for  ionic compounds with transition metals.

Transition metals are a group of elements in the periodic table located in the d-block, which includes the elements from 21 (Sc) to 30 (Zn), 39 (Y) to 48 (Cd), and 57 (La) to 80 (Hg).

They are characterized by having partially filled d orbitals in their electron configuration and are known for their unique physical and chemical properties, such as being able to form multiple oxidation states and exhibiting variable valence.

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The most likely problem with the titration set-up is an air bubble in the buret tip.

An air bubble in the buret tip can affect the accuracy of a titration by reducing the amount of titrant that is dispensed into the analyte solution. This can result in the appearance of passing the endpoint without a visible color change, as the titrant has not actually reacted with all of the analyte.

To avoid this problem, it is important to gently tap the side of the buret to remove any air bubbles before starting the titration, and to be mindful of air bubbles forming during the titration process. Additionally, checking the accuracy of the buret by performing a calibration before starting the titration can help to ensure that the results are reliable.

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When Earth's ice increases, ocean water gets less salty and when water evaporates from the oceans, the remaining water becomes more salty. Therefore, the correct option is option 2,3.

Concentration in chemistry refers to the quantity of a material in a certain area. The ratio of the solute in a solution to the solvent or whole solution is another way to define concentration.

Concentration may be expressed as per unit mass rather than volume. Although concentration is often used to describe chemical solutions, it may be computed for any combination. When Earth's ice increases, ocean water gets less salty and when water evaporates from the oceans, the remaining water becomes more salty  are true about the changing salt concentrations of ocean water.

Therefore, the correct option is option 2,3.

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The molality of a solution of water dissolved in ethanol is 0.0273 for which the mole fraction of water is 0.492.

Given the mole fraction of water (x_water) in the solution of water and ethanol, the molality (m) can be calculated as follows:

= m

= (x_water) / (MW_water)

where MW_water is the molecular weight of water (18.015 g/mol).

= m

= (0.492) / (18.015 g/mol)

= 0.0273 mol/kg

Therefore, the molality of the solution of water and ethanol is 0.0273 mol/kg.

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D) HBr, H307, Br", and H2O components expect to be present in the beaker after the compounds have had time to react.

Hydrogen bromide (HBr), a diatomic molecule, combines in water to create hydrobromic acid, a caustic acid. HBr has a pH of 0.21. One of the strongest mineral acids is this one. When highly toxic and highly soluble in water gaseous hydrogen bromide is dissolved in the water, an acidic environment and corrosive liquid (HBr) is generated.

Because of its capacity to establish intermolecular hydrogen bonds with water, HBr is soluble in water. The difference in electronegativity between H and Br causes a dipole to emerge in HBr.

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if you dissolve 0.3 moles of HBr in 1 L of water, what do you expect to be present in the beaker after the compounds have had time to react?

A)H2Br, OH, and H2O

B) H30*, Br", and H2O

C)BrOH and H307

D) HBr, H307, Br", and H2O

As per the given reaction, one mole of copper sulphate reacts to give one mole of Cu. 100 ml of 0.05 M copper sulphate contains 0.005 number of moles of CuSO₄.

Copper sulphate is an ionic compound formed by the reaction of copper metal with other metal sulphate. Copper sulphate undergoes redox reaction with other metals forming copper metal.

Given that, the reaction system contains 100 ml of 0.05 M of copper sulphate.

The no.of moles of copper sulphate = volume × molarity

no.of moles = 0.1 L × 0.05 M = 0.005 moles.

As per the reaction, 0.005 moles of copper sulphate will give 0.005 moles of Cu.

atomic mass of Cu = 63.5 g/mol

then mass of 0.005 moles of Cu = 0.005 g ×63.5 g/mol = 0.317 g.

Therefore, the mass of copper formed in this reaction is 0.317 g.

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Your question is incomplete. But your complete question probably was:

CuSO4 + Zn →→ Cu + ZnSO4

 if excess of zinc is added to 100ml of 0.05M CuSO4  the amount of copper formed is:

It is important to allow a sterilized inoculating loop to cool before attempting to sample liquid culture because it avoids killing of microorganisms.

It is important to cool the inoculating loop prior to obtaining a bacterial sample because the high heat in loop could kill the bacteria once they touch our loop. Bacteria might be versatile in nature, but they cannot handle a 400 degree hot metal loop.

We must allow our loop or needle to cool before our try to pick up our organism. If we pick up organism with a hot tool, oour cells will be killed. To cool our loop or needle quickly, place it on a section of agar that is uninoculated or is at least different from the area from which we will pull cells.

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It is true that under conditions of normal pressure and temperature, we can only make perfect calculations.

STP, or average temperature and humidity, refers to the conventional air temp at sea level. The temperature and pressure are, respectively, 0 °C and 1 atm.

It is now easier to compare different measurements for gases, such as the quantity of gas molecules in a given volume. There has to be a universal standard for pressure and temperature so that scientists may meaningfully compare various sets of data.

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The statement that best describes the relationship between changes in air pressure and wind speeds is:

Air moves in response to differences in atmospheric pressure. When there is a difference in pressure between two points, air will flow from high pressure to low pressure in an effort to balance out the difference. This flow of air creates wind.

The movement of air can also be influenced by the Earth's rotation and the heating of the Earth's surface by the sun, which creates complex patterns of air movement, including fronts, jet streams, and cyclones.

In general, wind moves from areas of high pressure to areas of low pressure in an effort to balance out differences in atmospheric pressure. The faster the pressure gradient, the stronger the wind speeds will be. When a high-pressure and a low-pressure air mass are far apart, the pressure gradient is steeper and the wind speeds are stronger.

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Chemical waste should be kept in the proper containers after the experiment. The EHS Hazardous Waste Program must be used to dispose of the majority of chemical wastes.

Any empty glass object or container can be put in a shattered glass container; it doesn't have to be broken. If the chemical is not on the list of acutely hazardous waste and the empty container is made of metal or plastic, it should be thrown out with regular trash.

Treatment options for hazardous waste encompass chemical, thermal, biological, and physical processes. Ion exchange, precipitation, oxidation, reduction, and neutralizing are some examples of chemical processes. High-temperature incineration is one thermal process that is able to cleanse and destroy some organic wastes.

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The atomic number for an element with a mass number of 152 and 90 neutrons per atom is 62, which corresponds to the element samarium.

What is samarium element?

Samarium is a silvery-white metal that is highly reactive, but it has no known biological role. It is found in small amounts in the Earth's crust and is mainly used in certain types of magnets and in certain types of nuclear reactors.

Calculation of atomic number:

The atomic number is the number of protons in the nucleus of an atom and is equal to the number of electrons in a neutral atom. Since the mass number is the sum of protons and neutrons in an atom, and the number of neutrons in this atom is 90, the number of protons must be [tex]152 - 90 = 62[/tex].

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The pH of a solution prepared by the addition of 10 ml of 0.002 M KOH (aq) to 10 ml of distilled water is closest to 13.

The addition of 10 ml of 0.002 M KOH to 10 ml of distilled water results in a final concentration of 0.002 M KOH in the solution. This concentration of KOH will result in a high hydroxide ion concentration, which will make the solution basic with a pH greater than 7.

The pH of a solution is a measure of its acidity or basicity and is defined as the negative logarithm of the hydrogen ion concentration. A pH of 7 is neutral, a pH less than 7 is acidic, and a pH greater than 7 is basic.

The pH of the solution can  be calculated using the equation:

pH = -log[OH-]

Since the concentration of hydroxide ions, [OH-], is equal to the concentration of KOH, 0.002 M, the pH of the solution is:

pH = -log(0.002) = 2 + log(10^3) = 2 + 3 = 5

Therefore, the pH of the solution is closest to 13.

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pH of diluted solution = 11

It is given that 10 mL of a 0.002 M KOH(aq) solution is diluted by adding 10 mL of distilled water. We are required to then calculate the pH of the diluted solution.

To solve this question, we can break it up into 3 sections:

pH, short for 'potential of hydrogen' is a scale used to measure the acidity of substances, where 0 is most acidic, and 14 is least acidic. pH is calculated with the formula:

[tex]\boxed{\large\textsf{$\sf pH=-\log_{10}\left[H^+\right]$, where $\rm \left[H^+\right]$ = concentration of H$^+$ ions}}[/tex]

Similarly, pOH is used to measure the basicity of substances, where 0 is the most basic, and 14 is the least basic. pOH is calculated with the formula:

[tex]\boxed{\large\textsf{$\sf pH=-\log_{10}\left[OH^-\right]$, where $\rm \left[OH^-\right]$ = concentration of OH$^-$ ions}}[/tex]

The mathematical relationship between pH and pOH is such that:

[tex]\boxed{\Large\textsf{14 = pH + pOH}}[/tex]

First we need to calculate the concentration of the diluted solution. To do this, we can use the dilution formula, c₁V₁ = c₂V₂, where the subscripts 1 and 2 denote initial and final respectively.

Hence, c₁ = 0.002 M, V₁ = 0.010 L, and V₂ = 0.010+0.010=0.020 L. Rearranging to find c₂:

[tex]\large\textsf{$\sf\displaystyle c_2=\frac{c_1V_1}{V_2}=\frac{0.002\times 0.010}{0.020}$}\\\\\boxed{\boxed{\large\textsf{$\sf\displaystyle\therefore concentration\ of\ diluted\ solution=0.001$ M }}}[/tex]

If we consider the dissociation reaction of KOH, which is a strong base and will fully dissociate into its ions:

[tex]\Large\text{$\rm KOH_{\,(aq)}\leftrightharpoons K^+_{\ (aq)}+OH^-_{\ (aq)}$}[/tex]

We can see that there is a 1:1 stoichiometric ratio between KOH and OH⁻ and therefore concentration of KOH = concentration of OH⁻.

Therefore, we can calculate pOH:

[tex]\boxed{\boxed{\large\textsf{$\sf\therefore pOH=-\log_{10}\left[0.001\right]=3$}}}[/tex]

Finally, we can use the fact that pH + pOH = 14 and so pH = 14 - pOH.

Therefore, pH = 11

[tex]\hrulefill[/tex]

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Burning a steel wheel, a candle, some sulfur, or a splinter produces new chemicals which is an observable evidence that suggests combustion is a chemical transformation.

The five elements of chemical change are: color change, precipitate or gas production, gas formation, odor change, and temperature change. A chemical reaction in which both light and heat can be seen is the burning of wood. We refer to a reaction as being exothermic when it produces heat. In other words, heat is transmitted from the reactants to the environment outside. When a chemical interacts with oxygen to release energy, a combustion event will always take place. For instance, methane burns in oxygen and produces carbon dioxide and water as byproducts. The oxidation of the carbon in the methane is demonstrated by the production of carbon dioxide. Also, burning of substance results in the release of heat and light energy, which is a sign of chemical change.

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A coulomb, or 1 C, has a mass of 6.25 1018 electrons. 6.25 billion billion electrons, to be exact.

A negatively charged neutrino known as an electron can either be free or attached to an atom (not bound). One of the three main types of molecules within an atom is an atom that is bonded to it; the other two being protons and neutrons.

Today, electrons are the name given to these negative charges cathode ray particles. Electrons are incredibly light, negatively charged particles. The total number atomic protons and neutrons in an atom equals the mass of that atom. .

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The atomic weight of copper is 63.55. The most likely decay mode for the radioactive isotope 68Cu is beta decay, where it transforms into 68Ni.

Beta decay is a type of radioactive decay in which a neutron in an unstable nucleus decays into a proton, releasing an electron and an antineutrino. In the case of 68Cu, which is a radioactive isotope, the beta decay process results in the transformation of the isotope into 68Ni. This happens because the neutron-proton ratio in 68Cu is too high, making the nucleus unstable. To achieve stability, a neutron in the nucleus decays into a proton, emitting an electron and an antineutrino. The result is a new element with a different atomic number, in this case, 68Ni. Beta decay is one of the main mechanisms by which unstable isotopes transform into more stable isotopes and is a crucial process in the life cycle of stars and in the formation of elements heavier than iron.

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Answer:

The reason he painted soup cans is that he liked soup." He was thought to have focused on them because they composed a daily dietary staple. Others observed that Warhol merely painted things he held close at heart. He enjoyed eating Campbell's soup, had a taste for Coca-Cola, loved money, and admired movie stars.

According to Beer-Lambert law, absorbance will also decrease by 42.4%

In chemistry, awareness is the abundance of a constituent divided by using the whole extent of an aggregate. several styles of mathematical description can be outstanding: mass concentration, molar awareness, quantity concentration, and volume awareness.

In technology, the amount of a substance, which includes salt, this is in a positive amount of tissue or liquid, along with blood. A substance becomes more concentrated while much less water is present. The concentration of the solution may be expressed in molarity, molality, normality, mole fraction, and many others. the attention of a substance is the amount of solute present in a given quantity of answer. Concentrations are commonly expressed in phrases of molarity, defined as the variety of moles of solute in 1 L of answer.

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There are total 300 CDs in the store, while  240 CDs are rock albums, which make up to 80% of the CDs.

Percentage is a way of representing a number as a fraction of 100. It is often used to express a portion or share of a total quantity. In mathematical terms, a percentage is a dimensionless number that represents a ratio of two quantities as a fraction of 100.

It can also be expressed as decimals or as a fraction. To convert a percentage to a decimal, divide the percentage by 100.

For example, 50% as a decimal would be 0.5. To convert a percentage to a fraction,  divide the percentage by 100 and then simplify the fraction as much as possible. 50% as a fraction would be 50/100 = 1/2

Calculation for the  total  number of CDs at a store

The equation for the above would be

240 CDs = 0.8 * x

The equation states that the number of rock albums (240 CDs) is equal to 80% of the total number of CDs in the store (x)

By isolating  x and dividing both sides of the equation by 0.8( that is simplification of 80%)

240 CDs / 0.8 = 0.8 * x / 0.8

240 CDs / 0.8 = x

Calculate the value of x by dividing 240 CDs by 0.8:

x = 240 CDs / 0.8

x = 300CDs

Therefore, the total number of CDs in a store are 300

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541.6 kJ heat is produced when 25.0 g of methanol reacts with 38.7 g of oxygen.  

We need to determine in this Thermochemical reaction ,which reactant is limiting by converting each mass into moles--->
Thermochemical reaction

25.0 g CH3OH / 32.0419 g/mol = .780 mol

38.7 g O2 / 31.9988 g/mol = 1.209 mol

Actual mol CH3OH / mol O2 = .780/1.209 = 0.645

mol CH3OH / mol O2 = 0.67

methanol is limiting here -

kJ = .746 mol CH3OH (1452 kJ/ 2 mol CH3OH) = 541.6 kJ

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It is important to wear safety goggles in the laboratory any time there are chemicals or laboratory equipment present in the lab.

This includes when using liquid chemicals, pouring or transferring chemicals at the lab bench, or simply because chemicals or equipment are present in the lab. Wearing safety goggles provides a barrier to protect your eyes from potential chemical splashes, dust, or other hazards that could cause injury or damage to your eyes. Additionally, wearing safety goggles is a basic safety measure that is typically required by laboratory protocols and recommended by laboratory safety guidelines. It is important to always follow established laboratory safety procedures and guidelines to minimize the risk of injury in the lab.

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The pressure, volume, temperature and mass can be determined from the experiment .

A force per unit area is referred to as pressure. It is measured in units of pascals (Pa) or pounds per square inch and is defined as the force per unit area that a substance exerts on its surroundings (psi). Pressure is a scalar quantity that is inversely proportional to the area the force acts on and proportionate to the force exerted on a surface.

a. pressure gauge or a manometer can be used to calculate the evaporated liquid's pressure.

b. You can measure the displacement of a known volume of air or use a gas metre to calculate the volume of the evaporated liquid.

c. You can use a thermometer, such as a mercury-in-glass or a digital one, to gauge the temperature of the vaporised liquid.

d. The mass of the liquid that has been vaporised can be calculated by weighing the container before and after the operation, then deducting the difference to get the liquid's mass.

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The value of the equilibrium constant "K" is the measure of how far the  reaction will proceed to  form products at a given temperature.

The rate of the reaction in forward direction Kf and the rate of the reaction in the backward direction Kb will give the value of equilibrium constant K.

It is given as K = Kf/Kb

A small value of K indicates that the reaction will favor in the direction of  the reactants. On the other hand, a large value of K indicates that the product will be formed in a higher proportion.

In an equilibrium reaction, the rate of the forward reaction is equal to the rate of the backward reaction.

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The average translational kinetic energy for oxygen molecule is 3691.4 j/mole.

Kinetic energy is defined as the power an object has because of its motion. If you want to boost up an object, then you must follow a force. Making use of the force requires you to do work. After work has been accomplished, energy is often transferred to the object, and the object might start moving with a new consistent speed.

The kinetic energy of an item is also defined as the electricity that it possesses due to its motion. Kinetic energy for the duration of its acceleration, the frame maintains this kinetic electricity except for its pace changes.

Transitional kinetic energy = 3/2 nRT

Transitional kinetic energy = 3/2 × 1 × 8.314 × 296 = 3691.4 j/mole

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Answer:

56.26%

Explanation:

The theoretical mass percent of barium in BaCl2 . 2H2O can be calculated as follows:

First, find the molar mass of BaCl2 . 2H2O:

BaCl2 . 2H2O = Ba + 2Cl + 2(H2O)

= 137.327 + 2 x 35.45 + 2 x 18.015

= 244.297 g/mol

Next, find the mass of barium in one mole of BaCl2 . 2H2O:

Ba = 137.327 g

Finally, divide the mass of barium by the total mass and multiply by 100:

(137.327 g / 244.297 g) x 100% = 56.26%

So, the theoretical mass percent of barium in BaCl2 . 2H2O is 56.26%.

Poles, Similar to a magnet's north and south poles, the two electrically charged regions on either end of the molecule are referred to as poles. A dipole is a molecule that has two poles.

A polar molecule is one that has an unbalanced charge on one side, according to the meaning of the term in chemistry. It has a partial charge area. One end is marginally favorable, the other marginally negative. They often have an unbalanced distribution of electrons and are asymmetrical.

Similar to a magnet's north and south poles, the two electrically charged regions on either end of the molecule are referred to as poles. Due to its two poles, a polar molecule is known as a dipole. A polar bond itself can also be referred to as a dipole.

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1. CH4, Methane

2. C2H6, Ethane

3. C3H8, Propane

4. C4H10, Butane

5. C5H12, Pentane

6. C6H14, Hexane

7. C7H16, Heptane

8. C8H18, Octane

Alkanes are a class of organic compounds made up of only carbon and hydrogen atoms. They are also known as "saturated hydrocarbons," as all of the carbon-carbon bonds are single bonds and there are no double or triple bonds between the carbon atoms.

The eight alkanes listed above are unbranched, meaning that they have a straight chain of carbon atoms, with no branches or side chains.

Each of these eight alkanes has a different number of carbon atoms, ranging from 1 carbon in methane to 8 carbons in octane. The naming convention for alkanes is based on the number of carbon atoms in the molecule, with the suffix "-ane" added to the end.

For example, ethane has 2 carbon atoms, and so it is named "ethane," while heptane has 7 carbon atoms, and so it is named "heptane."

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A chemical reaction yields 3 moles of lithium hydroxide (lioh), so 72 grams of lithium hydroxide are present.

The mass of a compound present in a mole of sample is ideally and obsoletely equivalent to the molar mass of the compound. The molar mass of the compound has been the sum of the constituent in a formula unit.

The molar mass of lithium hydroxide (mwt) has been given as the following:

M(wt) = M (Li) + M (o) + M (h)

Where, the mass of Li is 6.941 gm.

The mass of oxygen is 16 g

The mass of hydrogen is 1 gm.

Substituting the values for molar mass (mwt) of LiOH:

M(wt) = M (Li) + M (o) + M (h)

M(wt) = 24 gm

The molar mass of LiOH has been calculated to be 24 g.

Since, we are calculating for 3 moles.

So, 24x3 = 72 grams.

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