How many moles are in the number of molecules below? I only need to know the 5th question.

Answer: A mass of 0.518 g of phenol must be dissolved in 25.0 g of naphthalene to produce a solution that is 0.22 m in phenol.

Explanation:

Given: Mass of naphthalene = 25.0 g

Molality = 0.22 m

This means that 0.22 moles of solute is present per kg of solvent.

As 25.0 g  of naphthalene is there that will be 25.0 g per 1000 g (1 kg) is equal to 0.025 kg.

Hence, moles of phenol are calculated as follows.

[tex]Molality = \frac{moles}{mass (in kg)}\\0.22 m = \frac{moles}{0.025 kg}\\moles = 0.0055 mol[/tex]

Also, molar mass of phenol is 94.11 g/mol. This means that 1 mole of phenol contains 94.11 g.

Therefore, mass contained by 0.0055 moles of phenol is as follows.

[tex]0.0055 mol \times 94.11 g/mol \\= 0.518 g[/tex]

Thus, we can conclude that a mass of 0.518 g of phenol must be dissolved in 25.0 g of naphthalene to produce a solution that is 0.22 m in phenol.

Answer: The first law of thermodynamics is a statement of conservation of energy.

Explanation:

According to the first law of thermodynamics, heat provided to a system is actually the sum of internal energy and work done by the system or on the system.

Mathematically, [tex]\Delta Q = \Delta U + \Delta W[/tex]

The first law of thermodynamics also means that energy can neither be created nor it can be destroyed. Hence, energy is conserved.

Thus, we can conclude that the first law of thermodynamics is a statement of conservation of energy.

Answer:

A = 65.46 u

Explanation:

Given that,

The composition of zinc is as follows :

Zn-64 = 48.63%

Zn-66 = 27.90%

Zn-67 = 4.10%

Zn-68 = 18.75%

Zn-70 = .62%

We need to find the  average atomic mass of the given element. It can be solved as follows :

[tex]A=\dfrac{48.63\times 64+27.90\times 66+4.1\times 67+18.75\times 68+0.62\times 70}{100}\\A=65.46\ u[/tex]

So, the average atomic mass of zinc is 65.46 u.

Answer:

747.5 mL

Explanation:

Assuming ideal behaviour, we can solve this problem by using Boyle's law, which states that at constant temperature:

Where in this case:

We input the data given by the problem:

And solve for V₁:

Answer:

The student completed the experiment correctly and there were no errors in the experiment.

Explanation:

When a pea size amount of K2CO3 is dropped into a solution of HCl, the following reaction occurs;

K2CO3(s) + 2HCl(aq) ----> 2KCl(aq) + CO2(g) + H2O(l)

The gas CO2 does not support burning hence, when the student performed a splint test and observed that the splint was extinguished when he placed the splint into the test tube of the gas.

Hence, the experiment was properly conducted and the student completed the experiment correctly and there were no errors in the experiment.

Answer: It is true about the type of reaction that it is a single replacement reaction, and the cations in the two ionic compounds are different.

Explanation:

When one element in a compound is replaced by another element in a chemical reaction then it is called a single replacement reaction.

For example, [tex]K + NaCl \rightarrow KCl + Na[/tex]

Here, potassium metal is replacing the sodium metal in the sodium chloride compound.

As metals become cation by losing an electron in a chemical reaction.

Thus, we can conclude that it is true about the type of reaction that it is a single replacement reaction, and the cations in the two ionic compounds are different.

Answer: Its A

Explanation:

a single replacement reactions, and the ANIONS in the two ionic compounds are different

Answer:

7.640 kg

Explanation:

Step 1: Write the balanced complete combustion equation for ethanol

C₂H₆O + 3 O₂ ⇒ 2 CO₂ + 3 H₂O

Step 2: Calculate the moles corresponding to 4 kg (4000 g) of C₂H₆O

The molar mass of C₂H₆O is 46.07 g/mol.

4000 g × 1 mol/46.07 g = 86.82 mol

Step 3: Calculate the moles of CO₂ released

86.82 mol C₂H₆O × 2 mol CO₂/1 mol C₂H₆O = 173.6 mol CO₂

Step 4: Calculate the mass corresponding to 173.6 moles of CO₂

The molar mass of CO₂ is 44.01 g/mol.

173.6 mol × 44.01 g/mol = 7640 g = 7.640 kg

Answer: The statement it is endothermic because the energy required to break bonds in the reactants is less than the energy released when the products are formed, is true.

Explanation:

A chemical reaction in which heat energy  is released is called an exothermic reaction. For exothermic reactions, the value of [tex]\Delta H[/tex] is always negative.

A chemical reaction in which heat energy is absorbed is called an endothermic reaction. For endothermic reaction, the value of [tex]\Delta H[/tex] is always positive.

In endothermic reactions, energy required for breaking the bonds between reactants is less than the energy when products are formed due to which the value of [tex]\Delta H[/tex] remains positive.

Thus, we can conclude that the statement it is endothermic because the energy required to break bonds in the reactants is less than the energy released when the products are formed, is true.

It is endothermic because the energy required to break bonds in the reactants is greater than the energy released when the products are formed. The correct option is B.

The above reaction is endothermic because more energy is produced when new bonds form in the products (H = 920 kJ/mol) than is required to break bonds in the reactants (H = -750 kJ/mol).

In an endothermic process, more energy than is generated during bond creation is absorbed from the environment to dissolve existing bonds. This causes a net absorption of energy, which cools the system.

The reaction takes more energy than it releases, proving its endothermic nature, as seen by the positive difference between the energy needed to dissolve bonds and the energy released during bond formation.

Thus, the correct option is B.

For more details regarding endothermic process, visit:

https://brainly.com/question/28909381

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Your question seems incomplete, the probable complete question is:

During a reaction, ΔH for reactants is −750 kJ/mol and ΔH for products is 920 kJ/mol. Which statement is correct about the reaction? (5 points)

Group of answer choices

A. It is endothermic because the energy required to break bonds in the reactants is less than the energy released when the products are formed.

B. It is endothermic because the energy required to break bonds in the reactants is greater than the energy released when the products are formed.

C. It is exothermic because the energy required to break bonds in the reactants is less than the energy released when the products are formed.

D. It is exothermic because the energy required to break bonds in the reactants is greater than the energy released when the products are formed.

Answer:be careful and relax

Explanation:

Answer:

Hahaha be careful and relax

Answer:

First, the number of ammonium sulfide molecules should be calculated:

N = NA × n,

where NA - the Avogadro number, n - number of moles.

N (ammonium sulfide) = 6.022 × 1023 × 8.5 mol = 51.187 × 1023.

The moelcular formula of ammonium sulfide is (NH4)2S. It means that each molecule contains 8 hydrogen atoms.

As a result, 8.5 mol of (NH4)2S contain:

51.187 × 1023 × 8 = 41 × 1024 hydrogen atoms.

Answer: 41 × 1024 hydrogen atoms

Answer:

NH4Cl > Li2SO4 > CoCl3

Explanation:

Let us recall that the freezing point depression depends on the molality of the solution and the number of particles present.

Let us also recall that freezing point depression is a colligative property. It depends on the number of particles present in solution.

Usually, the more the number of particles present, the lower the freezing point. Hence, NH4Cl which has only two particles will have the highest freezing point while CoCl3 which has four particles will have the lowest freezing point.

Answer:

to the right (products side)

Explanation:

The equilibrium constant K describes the ratio between the concentration of products and reactants at equilibrium. For a general reaction:

a A + b B → c C + d D

The equilibrium constant expression is:

[tex]K = \frac{[C]^{c} [D]^{d} }{[A]^{a} [B]^{b} }[/tex]

A low value of K indicates that the concentration of products (C and D) is low in relation with the concentration of reactants (A and B).

Conversely, a high value of K indicated that the concentration of products is high compared with the concentration of reactants.

Since K = 6.4 × 10⁹ is a high value, the concentration of products is higher than the concentration of reactants at equilibrium. Thus, the position of the equilibrium is favored to the right.

Answer:

Explanation:

Answer is D 2,5-dimethylheptanal

You should accern the lowest possible number close to the parent name

Answer:

The answer is growth rate

Explanation:

it will help you

Answer:

"Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits, including apples, durians, pears, bananas, pineapples, and strawberries."

Explanation:

Answer:

i believe its A, potassium iodide in water

Explanation:

Answer:

See explanation

Explanation:

All molecules possess the London dispersion forces. However London dispersion forces is the only kind of intermolecular interaction that exists in nonpolar substances.

So, the only kind of intermolecular interaction that exists in dimethyl ether is London dispersion forces.

As for ethyl alcohol, the molecule is polar due to the presence of polar O-H bond. In addition to London dispersion forces, dipole-dipole interactions and specifically hydrogen bonding also occurs between the molecules.

Because ethyl alcohol is polar, it is more soluble in water than dimethyl ether.

Complete question:

What mass of steam initially at 120 ⁰C is needed to warm 200g of water in a 100 g glass container from 20.0 oC to 50.0 ⁰C

Answer:

the initial mass of the steam is 10.82 g

Explanation:

Given;

mass of water, m₁ = 200 g

mass of the glass, m₂ = 100 g

temperature of the steam = 120 ⁰C

initial temperature of the water, 20⁰ C

final temperature of the water, = 50⁰ C

let the mass of the steam = m

specific heat capacity of water c = 1 cal/g ⁰ C

specific heat capacity of glass c₂ = 0.2 cal/g ⁰ C

laten heat of vaporization of steam L = 540 cal/g

Apply principle of conservation energy;

Heat given off by the steam = Heat absorbed by water + heat absorbed by glass

[tex]mc\Delta T_1 + mL + mc\Delta T_2 = m_1c\Delta T_3 + m_2c_2\Delta T_3\\\\mc\Delta T_1 + mL + mc\Delta T_2 = [m_1c + m_2c_2]\Delta T_3[/tex]

m(1) (120 - 100)  +  m(540)  + m(1) (100 - 50) = [200(1)  +  100(0.2)] (50 - 20)

20m + 540m + 50m = 6600

610 m = 6600

m = 6600 / 610

m = 10.82 g

Therefore, the initial mass of the steam is 10.82 g

Answer:

Explanation:

The reaction is

H3Po4+3NH3\to→ (NH4)3PO4

Given,7.10g NH3=7.10g/molar mass of NH3

=7.10g/(17.031g/mol)

=0.416mol

From the reaction

3 mol ammonia reacted and produced 1 mole of ammoniam phosphate

So,One mole ammonia reacted and produced 1/ 3 mole ammonium phosphate.

And Also,0.416 mole ammonium reacted and produced (1/3)0.416=0.138 mole ammonium phosphate.

Hence 0.138mole=0.138mole*149.08 g/mole

               =20.573gm ammonium phosphate produced.

Hence 20.573g of ammonium phosphate is produced by the reaction of 7.10 g of ammonia.

Answer:

a

Explanation:

documentary is best researcher!.

Answer:

Certain ketones such as fructose can be oxidized by Benedict's reagent under basic conditions to form what type of compound

Explanation:

Benedict's solution is a mixture of copper sulfate, anhydrous sodium carbonate, and sodium citrate.

In presence of mild reducing agents, Cu(II) ion in Benedict's solution becomes the Cu(I) ion.

Fructose has an alpha-hydroxy ketone group.

It undergoes tautomerism and forms alpha-hydroxy aldehyde which gives a positive test with Benedict's reagent.

During this test, aldehydes will be converted into carboxylic acids.

The reaction of fructose with Benedict's reagent is shown below:

Answer:

1.5L of NaNO3 must be present

Explanation:

That contains 200g of sodium nitrate. Round to 2 significant digits

To solve this question we need to convert the mass of NaNO3 to moles using its molar mass (85g/mol). With the moles and the molar concentration we can find the volume in liters of the solution:

Moles NaNO3:

200g * (1mol / 85g) = 2.353 moles NaNO3

Volume:

2.353 moles NaNO3 * (1L / 1.60moles) =

Answer:

The answer is "It takes 1,70 mol of ethanol".

Explanation:

To make acetic acid, we must first write the balanced reaction that occurs of ethanol with oxygen

The response is balanced:

[tex]CH_3CH_2OH+O_2\to CH_3COOH+H_2O[/tex]

1 mol of ethanol creates 1 mol of According the equilibrium Ethanol moles, therefore, required 1.70 mol of water = 1.70 mol

Explanation:

So, first you will want to write the balanced chemical equation for this reaction.

Butane = [tex]C_4H_{10}[/tex]

[tex]2C_4H_{10}+13O_2=>10H_2O+8CO_2[/tex]

^ This ends up being your balanced chemical equation. Now, you can do the math!

[tex]1.57gC_4H_{10}*\frac{1molC_4H_{10}}{58.12gC_4H_{10}}*\frac{10molH_2O}{2molC_4H_{10}}*\frac{18gH_2O}{1molH_2O}[/tex]

After plugging this into a calculator, your final mass of water should be:

2.43gH2O

Answer: Sugar is added to water and initially completely dissolves, but eventually solid sugar collects on the bottom of the container. Sugar and water are both partially miscible. This produces a dynamic equilibrium. Ethanol (a liquid) is added to water and only a single layer is observed no matter how much ethanol is added. Ethanol and water are miscible.

Explanation:

When a substance (solute) dissolves partially in a solvent then it is known as partially miscible in the solvent. In such cases, a small amount of solute remains at the bottom of solution.

If a solute dissolves completely in solvent like water such that only one layer is seen in the solution then it means that the solute is miscible in solvent.

Thus, we can conclude that sugar is added to water and initially completely dissolves, but eventually solid sugar collects on the bottom of the container. Sugar and water are both partially miscible. This produces a dynamic equilibrium. Ethanol (a liquid) is added to water and only a single layer is observed no matter how much ethanol is added. Ethanol and water are miscible.

Answer:

liquid junction potentials

when a cell contains a boundary between two electrolytic solutions of different composition or concentration, a liquid junction potential is developed due to the "diffusion of the various components at characteristic rates in the boundary zone."

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the answer to the question is B.UV-B

Answer:

Li(s) + H2O(l) -----> LiOH(aq) + H2(g)

Ca(s) + 2H2O(l) ---------------> Ca(OH)2(aq) + H2(g)

Explanation:

Metals react with water to yield the metal hydroxide and hydrogen gas as shown in the answer above.

The reaction equations were balanced, the number of atoms of each element on both side of the reaction equation is exactly the same.

This is the way to write a balanced reaction equation for the species shown in the question.

Answer:

1.20x10⁻²⁰μL

Explanation:

1cm³ is equal to 1milliliter. As we must know, 1milliliter = 1000 microliters, 1000μL. To convert the 1.20x10⁻²³mL we need to use the conversion factor: 1mL = 1000μL.

The volume of tantalum in μL is:

1.20x10⁻²³mL * (1000μL /1L) = 1.20x10⁻²⁰μL

Answer:

B₂O₃

Explanation:

Step 1: Calculate the mass of oxygen in 150 mg of boron oxide

Of 150 mg of boron oxide, 46.6 mg belong to boron. The mass of oxygen is:

150 mg - 46.6 mg = 103.4 mg

Step 2: Calculate the percent by mass of each element

We will use the following expression.

%Element = mElement/mCompound × 100%

%B = 46.6 mg/150 mg × 100% = 31.1%

%O = 103.4 mg/150 mg × 100% = 68.9%

Step 3: Divide each percentage by the atomic mass of the element

B: 31.1/10.81 = 2.88

O: 68.9/16.00 = 4.31

Step 4: Divide both numbers by the smallest one (2.88)

B: 2.88/2.88 = 1

O: 4.31/2.88 ≈ 1.5

Step 5: Multiply both numbers by 2 so that they are integers

B: 1 × 2 = 2

O: 1.5 × 2 = 3

The empirical formula is B₂O₃.