Consider the evaporation of water. The standard change in the free energy is positive with ΔG∘rxn=+8.59kJmol. One might expect this process to occur in the opposite direction, with water vapor condensing into liquid water. How can the evaporation be spontaneously under normal conditions?

Answer:

go get the stuff.

Explanation:

Answer:

this the partial removal of a substance from a solution or mixture by dissolving it in another immiscible solvent in which it is more soluble.

Explanation:

83.6-24.2= 59.4 which is the change in heat

Considering the definition of percentage by mass and molality, the molality of Na₃PO₄ in the solution is 0.948 [tex]\frac{moles}{kg}[/tex].

The percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.

In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.

The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

[tex]percentage by mass=\frac{mass of solute}{mass of solution}x100[/tex]

Molality is the ratio of the number of moles of any dissolved solute to kilograms of solvent.

The Molality of a solution is determined by the expression:

[tex]molality=\frac{number of moles of solute}{kilograms of solvent}[/tex]

Considering 100 grams as a sample of the solution, then the value of the percentage of concentration given indicates that  13.5 g correspond to Na₃PO₄.

Remember that percent concentration by mass is calculated using the mass of solute and the mass of the solution, which includes both the solute and the solvent. Then:

mass solution= mass solute + mass solvent

100 g= 13.5 g + mass solvent

100 g - 13.5 g= mass solvent

86.5 g= mass solvent

Then, you know:

Then, replacing in the definition of molality:

[tex]molality=\frac{0.082 moles}{0.0865 kg}[/tex]

Solving:

molality= 0.948 [tex]\frac{moles}{kg}[/tex]

Finally, the molality of Na₃PO₄ in the solution is 0.948 [tex]\frac{moles}{kg}[/tex].

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Answer:

44

Explanation:

Answer: the answer is c.

Explanation:

i juss guessed and it was right?

The reduction half equation of the galvanic cell is is;  3Cu2+(aq)  + 3e ------> 3Cu(s).

A galvanic cell is a cell that produces chemical energy by a spontaneous chemical reaction. The equation of the reaction is; 2Cr(s) + 3Cu2+(aq) → 2Cr3+ (aq) + 3Cu(s). We can see that chromium was oxidized and copper was reduced.

Since reduction occurs at the cathode, it follows that the reduction half equation is;  3Cu2+(aq)  + 3e ------> 3Cu(s).

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Answer:

B

Explanation:

Option B is the correct answer. When you add 7 in front of the O2 in the left side, and then you add 4 and 6 in front of NO2 and H2O respectively, the number of oxygen atoms is the same in both sides.

The amount of the sample remaining at 4pm is 0.0625 g

We'll begin by calculating the number of half-lives that has elapsed

Half-life (t½) = 1 hour

Time (t) = 4 hour

n = t / t½

n = 4 / 1

Number of half-lives (n) = 4

Initial amount (N₀) = 1 g

[tex]N = \frac{N_0}{ {2}^{n}} \\ \\ N = \frac{1}{ {2}^{4}} \\ \\ N = \frac{1}{16} \\ \\ N = 0.0625 \: g[/tex]

Thus, the amount remaining at 4pm is 0.0625 g

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Prior to writing the chemical formula of magnesium chloride, a question which any student will need to ask is: A.  What are the oxidation numbers of each atom?

A chemical formula can be defined as a scientific notation that is used to show (represent) the type and total number of atoms that constitute a particular chemical molecule or compound, by using the oxidation number, chemical symbols and subscripts.

Hence, a student would need to know the oxidation numbers of each atom when magnesium chloride is formed after a chemical reaction.

In Chemistry, an oxidation number represents the number of electrons gained or lost by an atom of a chemical element during a chemical reaction.

In conclusion, when magnesium chloride is formed, a question which the student will need to ask prior to writing the chemical formula is "what are the oxidation numbers of each atom?"

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Answer:

Explanation:

Answer:

Explanation:

Thin-layer chromatography (TLC) is a chromatography technique used to separate non-volatile mixtures. ... After the sample has been applied on the plate, a solvent or solvent mixture (known as the mobile phase) is drawn up the plate via capillary action.

Answer:

1.false

2.true

3.true

4.true

5.false

6.false

7.false

8.true

9.false

10.true

Explanation:

I took the test

Using Hess's law we found:

1) By adding reaction 10.2 with the reverse of reaction 10.1 we get reaction 10.3:

KOH(aq) + HCl(aq)  → H₂O(l) + KCl(aq)   ΔH  (10.3)

2) The ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy (ΔH).    

The reactions of dissolution (10.1) and neutralization (10.2) are:

KOH(s) → KOH(aq)   ΔHsoln    (10.1)

KOH(s) + HCl(aq) → H₂O(l) + KCl(aq)     ΔHneut     (10.2)

1) According to Hess's law, the total change in enthalpy of a reaction resulting from differents changes in various reactions can be calculated as the sum of all the enthalpies of all those reactions.      

Hence, to get reaction 10.3:

KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq)    (10.3)

We need to add reaction 10.2 to the reverse of reaction 10.1

KOH(s) + HCl(aq) + KOH(aq) → H₂O(l) + KCl(aq) + KOH(s)

Canceling the KOH(s) from both sides, we get reaction 10.3:

KOH(aq) + HCl(aq)  → H₂O(l) + KCl(aq)    (10.3)

2) The change in enthalpy for reaction 10.3 can be calculated as the sum of the enthalpies ΔHsoln and ΔHneut:

[tex] \Delta H = \Delta H_{soln} + \Delta H_{neut} [/tex]

The enthalpy of reaction 10.1 (ΔHsoln) changed its sign when we reversed reaction 10.1, so:

[tex] \Delta H = \Delta H_{neut} - \Delta H_{soln} [/tex]

Therefore, the ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy ΔH.

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I hope it helps you!

Answer:

A mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium.

Explanation:

While waves can move over long distances, the movement of the medium of transmission—the material—is limited. Therefore, the oscillating material does not move far from its initial equilibrium position.

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hope this helped!

✼-answers by brookeangelx

The wave transmits energy from one point to another in the form of signals. Some waves require a medium for propagation while some others does not require a medium for the propagation.

The mechanical wave is defined as the wave which involves the oscillation of matter and it is responsible for the transfer of energy through a medium. These types of waves does not need a medium for propagation.

The mechanical waves cannot travel through vacuum. Some of the examples of mechanical waves are sound waves, water waves, seismic waves, etc. These waves are not capable of transmitting its energy through a vacuum.

The sound wave is a mechanical wave and the medium which it propagates can be solid, liquid or gas. It can travel fastest in solids and slower in gases.

Thus mechanical wave is an oscillation of matter.

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Rutherford proposed the nuclear model of atom. The only one model which can be inferred from this model is nucleus with protons and revolving electrons around.

Rutherford proposed some aspects of atomic structure based on his gold foil experiment. He discovered that the alpha ray is scattering from foil by the repulsion it experienced from the metal.

This results lead to the discovery of positively charged particles in atom latter called as protons. Rutherford proposed that theses protons are located inside the nucleus and the electrons are revolving around the nucleus.

Latter Niels Bohr his student interpreted the nuclear model of Rutherford with quantum mechanics and theory of max planck and he proposed the equations for the determination of energy and momentum of electrons and the radius of atom.

Therefore, no other inferences except the presence of protons and revolving electrons can be obtained from Rutherford's model of atom.

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Answer:

increase the number of gas particles

Explanation:

This  problem provides the molar mass and radius of a metal that has an BCC unit cell and the density is required.

Firstly, we consider the formula that relates molar mass and also includes the Avogadro's number and the volume of the unit cell:

[tex]\rho =\frac{Z*M}{V*N_A}[/tex]

Whereas Z stands for the number of atoms in the unit cell, M the molar mass, V the volume and NA the Avogadro's number. Next, since BCC is able to hold 2 atoms and M and NA are given, we calculate the volume of the atom in the unit cell given the radius in meters:

[tex]V=a^3=(\frac{4R}{\sqrt{3} } )^3=(\frac{4*1.74x10^{-10}m}{\sqrt{3} } )^3=6.49x10^{-29}m^3[/tex]

And finally the required density in g/cm³:

[tex]\rho =\frac{2*341.1g/mol}{6.49x10^{-29}m^3\frac{m^3}{atom} *6.022x10^{23}\frac{atom}{mol} } =17455257.8g/m^3\\\\\rho=17.5g/cm^3[/tex]

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Answer:

310K

Explanation:

Rearrange PV=nRT to get T=PV/nR

T=(2.0L)(0.75atm)/(0.5mol)(0.08206)

=36.5 or 37

add 273 for K to get

310

Answer:

Neon 10,  mass: 20.18

Explanation:

Answer:

Forged parts are often tougher than cast parts. This can be determined by performing tensile tests on various areas on the parts. Additionally, the microstructures of forged and cast parts can be used to determine if a part was forged or cast. The microstructure of a cast part will have a more uniform grain structure.

Explanation:

Answer:

i can't understand the question

Answer:

B

Explanation:

as temperature rises, the particles gain kinetic energy (they will move faster) so if temperatures stays constant, so will the movement or vibration of the particles

Answer:

im pretty sure its 2.7 gms

Explanation:

im not for sure tho

The number of moles of gas B present in the gas mixture is 2.72 moles.

The given parameters;

The total number of moles of the gases is calculated by applying ideal gas law;

PV = nRT

where;

R is ideal gas constant = 0.0821 L.atm./mol.K

n is the total mole of the gases

[tex]n =\frac{PV}{RT} \\\\n = \frac{8 \times 14}{0.0821 \times 323} \\\\n = 4.22 \ moles[/tex]

The number of moles of gas B is calculated as follows;

[tex]n_B = 4.22 - n_A\\\\n_B = 4.22 - 1.5\\\\n_B = 2.72 \ moles[/tex]

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Answer:

Atoms themselves do not have a smell. Molecules do.

Explanation:

What happens is that particular molecules bind to receptors in our nose, activating nerves, that then send signals to our brain, which we then interpret and perceive as “smells”. Different molecules bind to different receptors, which is why we can perceive a number of different smells

Answer:

a. the breaking of bonds

Answer:

B

Explanation:

Hey, I am almost positive that the answer to this question is B. The breaking of bonds uses the energy but when they are created it releases energy. I hope this helps, Have a good day!

Answer:

It is an unstable form of a chemical element that releases radiation as it breaks down and becomes more stable.