The melting point of H₂O(s) is 0 °C. Would you expect the melting point of H₂S(s) to be 85 °C, 0 °C or -85 °C.? Justify your choice

This problem is describing the equilibrium whereby hydrofluoric acid decomposes to hydrogen and fluorine gases at 298 K whose equilibrium constant is 8.70x10⁻³, the equilibrium concentrations of all the reactants are both 1.33x10⁻³ M and asks for the initial concentration of hydrofluoric acid which turns out to be 2.86x10⁻³ M.

Then, we can write the following equilibrium expression for hydrofluoric acid once the change, [tex]x[/tex], has taken place:

[tex][HF]=[HF]_0-2x[/tex]

Now, since both products are 1.33x10⁻³ M we infer the reaction extent is also 1.33x10⁻³ M, and thus, we can calculate the equilibrium concentration of HF via the law of mass action (equilibrium expression):

[tex]8.70x10^{-3}=\frac{(1.33x10^{-3} M)^2}{[HF]} }[/tex]

[tex][HF]=\frac{(1.33x10^{-3} M)^2}{8.70x10^{-3}} }=2.03x10^{-4}M[/tex]

Finally, the initial concentration of HF is calculated as follows:

[tex][HF]_0=[HF]+2x=2.033x10^{-4}+2*(1.33x10^{-3})=2.86x10^{-3}M[/tex]

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Answer:

Explanation:

First you will find the mole from the molarity and then the desired mass from the mole.

Answer:  251 K

Explanation: hope this helps :)

In this case, according to the given information about the oxidation numbers and the compounds given, it turns out possible to figure out the oxidation number of manganese in both MnI2, manganese (II) iodide and MnO2, manganese (IV) oxide, by using the concept of charge balance.

Thus, we can define the oxidation state of iodine and oxygen as -1 and -2, respectively, since the former needs one electron to complete the octet and the latter, two of them.

Next, we can write the following [tex]x[/tex], since manganese has five oxidation states, and it is necessary to calculate the appropriate ones:

[tex]Mn^xI_2^-\\\\Mn ^xO_2^{-2}[/tex]

Next, we multiply each anion's oxidation number by the subscript, to obtain the following:

[tex]Mn^xI_2^-\rightarrow x-2=0;x=+2\\\\Mn ^xO_2^{-2}\rightarrow x-4=0;x=+4[/tex]

Thus, the correct choice is Manganese has an oxidation number of +2 in Mnl2 and +4 in MnO2.

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Answer:,   Correct option is    0.288m/s

Explanation:    

The relationship between the velocity of the wave, its wavelength and frequency is given by the formula

Wavelengthλ=

Frequency(ν)

Speed(v)

​

,

where, v - velocity of the wave

           λ - wavelength of the wave

          f - frequency of the wave.

In the question it is given that the frequency is 4.8 Hz and the wavelength is 6.0 cm, that is, 0.06 meters.

The velocity of the sound is calculated as follows.

v=f×λ=4.8 Hz×0.06 m=0.288 m/s

Hence, the speed of the water wave is 0.288 m/s.

Answer:315 - 282 = 173?

Explanation:

To extract hydrogen from water, researchers insert two electrodes across the water and pass current, which can separate the hydrogen from water. The process called electrolysis of water. ... An electric field applied through the cobalt oxide to water molecules resulted in the electrolysis of water

Hydrogen gas is an environment-friendly fuel — it produces water on combustion in the presence of oxygen. ... To extract hydrogen from water, researchers insert two electrodes across the water and pass current, which can separate the hydrogen from water. The process called electrolysis of water.

Answer:

go get the stuff.

Explanation:

Answer:

heat the solution

Explanation:

i think

Answer:

The way to make a supersaturated solution is to add heat, but just a little heat won't do the job. You have to heat the water close to the boiling point. When the water gets this hot, the water molecules have more freedom to move around, and there is more space for solute molecules between them.

The volume of sulphuric acid, H₂SO₄ needed for the complete reaction with 72.2 g of sodium hydroxide, NaOH is 5.31 L

We'll begin by calculating the number of mole in 72.2 g of NaOH. This can be obtained as follow:

Mass of NaOH = 72.2 g

Molar mass of NaOH = 23 + 16 + 1 = 40 g/mol

Mole = mass / molar mass

Mole of NaOH = 72.2 / 40

2NaOH + H₂SO₄ —> Na₂SO₄ + 2H₂O

From the balanced equation above,

2 moles of NaOH reacted with 1 mole of H₂SO₄.

Therefore,

1.805 mole of NaOH will react with = 1.805 / 2 = 0.9025 mole of H₂SO₄.

Mole of H₂SO₄ = 0.9025 mole

Molarity of H₂SO₄ = 0.170 M

Volume = mole / Molarity

Volume of H₂SO₄ = 0.9025 / 0.170

Thus, the volume of H₂SO₄ needed for the reaction is 5.31 L

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This question is asking for a method for the determination of the freezing point in a solution that does not have a noticeable transition in the cooling curve, which is basically based on a linear fit method.

The first step, would be to understand that when the transition is well-defined as the one on the attached file, we can just identify the temperature by just reading the value on the graph, at the time the slope has a pronounced change. For instance, on the attached, the transition occurs after about 43 seconds and the freezing point will be about 4 °C.

However, when we cannot identify a pronounced change in the slope, it will be necessary to use a linear fit method (such as minimum squares) to figure out the equation for each segmented line having a significantly different slope and then equal them so that we can numerically solve for the intercept.

As an example, imagine two of the segmented lines have the following equations after applying the linear fit method:

[tex]y=-3.5 x + 25\\\\y=-0.52 x + 2[/tex]

First of all, we equal them to find the x-value, in this case the time at which the freezing point takes place:

[tex]-3.5 x + 25=-0.52 x + 2\\\\-3.5 x+0.52 x =2-25\\\\x=\frac{-23}{-2.98}=7.72[/tex]

Next, we plug it in in any of the trendlines to obtain the freezing point as the y-value:

[tex]y=-3.5 (7.72) + 25\\\\y = 1.84[/tex]

This means the freezing point takes place after 7.72 second of cooling and is about 1.84 °C. Now you can replicate it for any not well-defined cooling curve.

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Explanation:

the investigation lasts for 7 days.

hope this helps you.

As the solar nebula cooled METAL compounds are the first to condense from a gas to a solid. The solar nebula gave birth to the Solar system.

A solar nebula is a disc-shaped cloud of gases and grain dust, which gave birth to the Sun and planets of the Solar system, approximately 4.6 billion years ago.

The solar nebula is at the beginning a mixture of interstellar gases (hydrogen and helium) and dust grains.

As the solar nebula cools, heavy elements such as metals in the disk condensate into planetesimals.

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-Sound waves transfer energy by the motion of particles.

Explanation:

These particle-to-particle, mechanical vibrations of sound conductance qualify sound waves as mechanical waves. Sound energy, or energy associated with the vibrations created by a vibrating source, requires a medium to travel, which makes sound energy a mechanical wave.

Sound waves transfer energy by the motion of particles considered a type of mechanical energy.

Potential energy plus kinetic energy are combined to form mechanical energy. According to the concept of mechanical energy conservation, mechanical energy remains constant in an isolated system that is solely exposed to conservative forces.

The quantity of energy that a force transfers is known as mechanical work. It is a scalar quantity with joules as its SI unit, much as energy.

Since there are only microscopic forces generated by atomic collisions and no macroscopically quantifiable force, heat conduction is not regarded as a kind of work.

Transverse, longitudinal, and surface waves are the three different forms of mechanical waves. When the wave's energy goes through them, they behave differently in terms of how the medium's particles move.

Thus, option C is correct.

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Answer:

D . GOD BLESS .

Explanation:

The molarity of the solution is 0.01.

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Answer:

›› FeBr2 molecular weight. Molar mass of FeBr2 = 215.653 g/mol. This compound is also known as Iron(II) Bromide. Convert grams FeBr2 to moles or moles FeBr2 to grams. Molecular weight calculation: 55.845 + 79.904*2 ›› Percent composition by element

Explanation:

If 38.6 grams of iron react with an excess of bromine gas, the mass of FeBr2 can form is 149 grams.

Mass is defined as a way to gauge how much matter there is in a substance or thing. The kilogram (kg) is the fundamental SI unit of mass, while lower masses can also be measured in grams (g). Atoms make up everyday matter. A majority of an atom's mass is contained in its nucleus.

Given Fe = 38.6 g.

Fe has a molar mass = 55.845 g/mol.

Given mass/molar mass equals 38.6g/55.845gmol-1, or 0.6912 moles of iron.

The reaction is described as Fe + Br2 FeBr2.

One mole Fe yields 1 mole of FeBr2.

FeBr2 would be produced from 0.6912 moles of Fe.

FeBr2 has a molar mass of 215.65 g/mol.

Moles of FeBr2 x Molar mass of FeBr2

= 215.65 g/mole x 0.6912 mole

= 149.06 g FeBr2 produced is the formula.

Thus, if 38.6 grams of iron react with an excess of bromine gas, the mass of FeBr2 can form is 149 grams.

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Using melting and boiling temperature, hardness and electric current passing testing.

Ionic solids are materials that have a strong bond between their ions, thus producing well-defined shapes.

In addition, due to this strong attraction, the boiling and melting temperatures of these materials are very high, in addition to the resistance to breakage presented by them.

Finally, ionic solids are also excellent conductors of electricity.

So, their properties used to determine whether or not they are ionic solids are  melting and boiling temperature, hardness and electric current passing testing.

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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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This problem is describe the mole-ratio composition of an allow composed by tin, lead and cadmium. Ratios are given as Sn:Pb 2.73:1.00 and Pb:Cd is 1.78:1.00, and we are asked to calculate the mass percent compositon of Pb in the allow.

In this case, according to the given information, it turns out possible realize that the following number of moles are present in the alloy, according to the aforementioned ratios:

[tex]2.73mol Sn\\\\1.00molPb\\\\\frac{1.00molPb*1.00molCd}{1.78molPb}= 0.562molCd[/tex]

Next, we calculate the masses by using each metal's atomic mass:

[tex]m_{Sn}=2.73mol*\frac{118.7g}{1mol}=324.05g\\\\ m_{Pb}=1.00mol*\frac{207.2g}{1mol}=207.2g\\\\m_{Cd}=0.562mol*\frac{112.4g}{1mol}=63.2g[/tex]

Thus, the mass percent composition of each metal is shown below:

[tex]\%Sn=\frac{324.05g}{324.05g+207.2g+63.2g} *100\%=54.5\%\\\\\%Pb=\frac{207.2g}{324.05g+207.2g+63.2g} *100\%=34.9\%\\\\\%Cd=\frac{63.2}{324.05g+207.2g+63.2g} *100\%=10.6\%[/tex]

So that of lead is 34.9 %.

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Answer:Nothing

Explanation:

The answer is nothing the tempatature isnt matched with the degrees this is false

Explanation:

filling air inside an empty o2 medal containers, if air is added, the air inside, creates volume inside.

due to heat, weather,... depending on what indoor or outdoor storage said containers r placed in,;

So, I can't give you an answer, due to lack of details..sorry...

The mole fraction of N₂ after the mixture of 4.0 L of N₂ at 15 atm with 4.0 L of H₂ at 7.0 atm is 0.68.

We can calculate the mole fraction of N₂ with the following equation:

[tex] X_{N_{2}} = \frac{n_{N_{2}}}{n_{t}} = \frac{n_{N_{2}}}{n_{N_{2}} + n_{H_{2}}} [/tex]   (1)

The number of moles of N₂ and H₂ can be found with the ideal gas law:

[tex] PV = nRT [/tex]

Where:

P: is the pressure

R: is the gas constant

T: is the temperature

V: is the volume

For nitrogen gas we have:

[tex] n_{N_{2}} = \frac{P_{N_{2}}V_{N_{2}}}{RT} [/tex]   (2)

And for hydrogen:

[tex] n_{H_{2}} = \frac{P_{H_{2}}V_{H_{2}}}{RT} [/tex]   (3)

After entering equations (2) and (3) into (1), we get:

[tex] X_{N_{2}} = \frac{\frac{P_{N_{2}}V_{N_{2}}}{RT}}{\frac{P_{N_{2}}V_{N_{2}}}{RT} + \frac{P_{H_{2}}V_{H_{2}}}{RT}} [/tex]  

Since RT are constants, we have:

[tex] X_{N_{2}} = \frac{P_{N_{2}}V_{N_{2}}}{P_{N_{2}}V_{N_{2}} + P_{H_{2}}V_{H_{2}}} [/tex]                

We know that:

[tex] P_{N_{2}} = 15 atm[/tex]                

[tex] V_{N_{2}} = 4.0 L[/tex]                

[tex] P_{H_{2}} = 7.0 atm[/tex]                

[tex] V_{H_{2}} = 4.0 L[/tex]          

so:

[tex] X_{N_{2}} = \frac{15 atm*4.0 L}{15 atm*4.0 L + 7.0 amt*4.0 L} = 0.68 [/tex]                

Therefore, the mole fraction of N₂ is 0.68.

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Answer:

Mercury (I) phosphate with the chemical formula  (Hg2)3(PO4)2 has 16 atoms.

Sum of all the atoms = 6+2+8

                                   = 16 atoms

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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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