Pure water at 25°C ionizes as what?

Answer:

Dissociated state is the predominant one

Explanation:

When a molecule with pKa of 4.52 is in an aqueous solution at pH = 4.0, follows the H-H equation, thus:

pH = pKa + log₁₀ [A⁻] / [HA]

Where [A⁻] is the dissociated state and [HA] represents the protonated state

Replacing:

4.0 = 5.2 + log₁₀ [A⁻] / [HA]

-1.2 = log₁₀ [A⁻] / [HA]

0.063 =  [A⁻] / [HA]

[HA]  = 16 [A⁻]

That means you have 16 times more [HA] than [A⁻] and the dissociated state is the predominant one

Answer:

98.3 gradius Celsius

Explanation:

This problem is solved using the Ideal Gas Equation

pV = nRT

...

Please see the step-by-step solution in the picture attached below.

Hope this answer can help you. Have a nice day!

Answer:

the European countries grew together.

Explanation:

Europe saw human inflows from east and southeast.

the Roman Empire came to dominate the entire Mediterranean basin.

European politics from 1947 to 1989 made the European countries grew together.

Answer:

$95

Explanation:

.75 x 120 = 90

90+5 = 95

Answer:

C)

Explanation:

JUST DID IT

Answer:

A D E

Explanation:

just did it

Answer:

A. The Swallowing reflex

Explanation:

Dysphagia Is a a condition that makes swallowing difficult.

Answer:

The absorption and strength of the H-beta lines change with the temperature of the stellar surface, and because of this, one can find the temperature of the star from their absorption lines and strength. To better comprehend, let us look into the concept of the atom's atomic structure.  

Atoms possess distinct energy levels and these levels of energy are constant, that is, the temperature has no influence on it. However, temperature possesses an influence on the electron numbers found within these levels of energy. Therefore, to generate an absorption line of hydrogen in the electromagnetic spectrum's visible band, the electrons are required to be present in the second energy level, that is when it captivates a photon.  

Therefore, after captivating the photons the electrons jump from level 2 to level 4, which shows that there is an increase in the stellar surface temperature and at the same time one can witness a decline in the strength of the H-beta lines. In case, if the temperature of the surface increases too much, then one will witness no attachment of electron with the hydrogen atom and thus no H lines, and if the temperature of the surface becomes too low, then the electrons will stay in the ground state and no formation of H lines will take place in that condition too.  

Hence, to generate a very robust H line, after captivating photons the majority of the electrons are required to stay in the second energy level.  

Answer:

[tex]M_2=0.51M[/tex]

Explanation:

Hello,

In this case, for this dilution process, we understand that the moles of the solute (potassium nitrate) remain unchanged upon the addition of diluting water. However, the resulting or final volume includes the added water as shown below:

[tex]V_2=300mL+50mL=350mL[/tex]

In such a way, we are able to relate the solution before and after the dilution by:

[tex]V_1M_1=V_2M_2[/tex]

Hence, we solve for the final molarity as:

[tex]M_2=\frac{M_1V_1}{V_2}=\frac{0.6M*300mL}{350mL}[/tex]

Best regards.

[tex]M_2=0.51M[/tex]

Answer:

LiF and RbBr

Explanation:

Salt is an ionic compound that is made from the reaction of an acid and a base solution. Salts dissolve in water to give solutions that are acidic, basic, or neutral.

Salt formed from a strong acid and a weak base will make an acidic solution when added to water. The reason this occurs is because when the salt dissociates, the conjugate acid of the weak base will donate a proton, or one hydrogen ion, to water and form hydronium ion.

If a salt is formed from a weak acid and a strong base, it dissolves in water and the conjugate base of the weak acid will accept a proton from water and yield the hydroxide ion. Hence the solution of the salt will be basic.

If the salt is formed from a strong acid and a strong base, the salt is neutral when dissolved in water. Both LiF and RbBr are formed from strong acids and strong bases hence they will have a pH of 7.0 in solution.

LiF RbBr NaClO4 NH4Cl is = LiF and RbBr The correction is 'C'.

Salt is an ionic mixture that is made from the reaction of an acid and a base resolution. Salts liquefy in water to give solutions that are acidic, basic, or neutral.

Salt constructed from a strong acid and a breakable base will make an acidic solution when added to water. The reason this occurs is that when the salt dissociates, the conjugate acid of the weak base will donate a proton, or one hydrogen ion, to water and form a hydronium ion.

If a grain of salt is formed from a weak acid and a powerful ground, it liquefies in water and the conjugate bottom of the weak acid will accept a proton from water and yield the hydroxide ion. Therefore, the solution of the salt will be basic.

If the salt is formed from a strong acid and a strong bottom, the salt is neutral when liquefied in water. Both LiF and also RbBr are formed from strong acids and powerful bases hence they will have a pH of 7.0 in resolution.

Therefore, the Correct option is 'C'

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Answer:

2.0 x 10^-2 kg/mol

Explanation:

Answer:

A. Ductility, because it can be observed by altering the shape of the substance  

Explanation:

Changing the shape of a substance does not change its identity.

Answer:

1.3×10⁻³ M

Explanation:

Hello,

In this case, given the dissociation reaction of acetic acid:

[tex]CH_3CO_2H(aq) + H_2O(l) \rightleftharpoons H_3O^+(aq) + CH_3CO_2^-(aq)[/tex]

We can write the law of mass action for it:

[tex]Ka=\frac{[H_3O^+][CH_3CO_2^-]}{[CH_3CO_2H]}[/tex]

Of course, excluding the water as heterogeneous substances are not included. Then, in terms of the change [tex]x[/tex] due to the dissociation extent, we are able to rewrite it as shown below:

[tex]1.8x10^{-5}=\frac{x*x}{0.100-x}[/tex]

Thus, via the quadratic equation or solve, we obtain the following solutions:

[tex]x_1=-0.00135M\\x_2=0.00133M[/tex]

Obviously, the solution is 0.00133M which match with the hydronium concentration, thus, answer is: 1.3×10⁻³ M in scientific notation.

Regards.

Answer:

1.3×10^-3 M

Explanation:

Step 1:

Data obtained from the question:

Equilibrium constant (Ka) = 1.8×10^-5

Concentration of acetic acid, [CH3COOH] = 0.100 M

Concentration of hydronium ion, [H3O+] =..?

Step 2:

The balanced equation for the reaction.

CH3CO2H(aq) + H2O(l) ⇌ H3O+(aq) + CH3CO2-(aq)

Step 3:

Determination of concentration of hydronium ion, [H3O+].

This can be obtained as follow:

Ka = [H3O+] [CH3CO2-] / [CH3CO2H]

Initial concentration:

[CH3COOH] = 0.100 M

[H3O+] = 0

[CH3CO2-] = 0

During reaction

[CH3COOH] = – y

[H3O+] = +y

[CH3CO2-] = +y

Equilibrium:

[CH3COOH] = 0.1 – y

[H3O+] = y

[CH3CO2-] = y

Ka = [H3O+] [CH3CO2-] / [CH3CO2H]

1.8×10^-5 = y × y / 0.1

Cross multiply

y^2 = 1.8×10^-5 x 0.1

Take the square root of both side

y = √(1.8×10^-5 x 0.1)

y = 1.3×10^-3 M

[H3O+] = y = 1.3×10^-3 M

Therefore, the concentration of the hydronium ion, [H3O+] is 1.3×10^-3 M

Answer:

this si from google hope it helps

Explanation:

The Main Causes of Water Pollution in the U.S.

Runoff from Agricultural Operations. Agriculture represents one of the biggest sources of water pollution in the country. ...

Runoff and Nonpoint Source Pollution. ...

Industrial Activities. ...

Leakage from Underground Storage and Piping. ...

Leaking Sewers. ...

Vehicle Emissions. ...

Landfill Leakage. ...

Hazardous Waste.

Answer:

Runoff and Non-point Source Pollution.

Explanation:

it's caused by rainfall or snow-melt moving over and through the ground. As the runoff moves, it picks up and carries away natural and human-made pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters and ground and NPS is it's abbreviation.

Answer:

2.6 × 10³ g Al

74 mol O₂

Explanation:

Aluminum oxide decomposes into aluminum and oxygen, according to the following balanced equation.

2 Al₂O₃ ⇒ 4 Al + 3 O₂

Step 1: Calculate the moles corresponding to 5.0 kg of aluminum oxide

The molar mass of aluminum oxide is 101.96 g/mol.

[tex]5.0 \times 10^{3} g \times \frac{1mol}{101.96g} = 49mol[/tex]

Step 2: Calculate the mass of aluminum formed

We will use the following relations.

[tex]49molAl_2O_3 \times \frac{4molAl}{2molAl_2O_3} \times \frac{26.98gAl}{1molAl} = 2.6 \times 10^{3} gAl[/tex]

Step 3: Calculate the moles of oxygen produced

The molar ratio of Al₂O₃ to O₂ is 2:3. Then,

[tex]49molAl_2O_3 \times \frac{3molO_2}{2molAl_2O_3} =74molO_2[/tex]

Answer:

the motion of gravity

Explanation:

Answer:

its c

Explanation

advhuosijoklxcmnjdabsuhggggabciaciudeifweingivg eygerigsygfe97rsghisdcvhbsduigwiugfu9uigdgiurfgyisdgfsdgfegiygewifgsdygfewusgfuyesigf7wgfiesgfiusgdfies

Answer:

The reaction involves two steps and occurs fastest with tertiary alkyl halides

Explanation:

To solve such this we must know the concept of nucleophilic substitution reaction. The reaction involves two steps and occurs fastest with tertiary alkyl halides. Therefore, the correct option is option A.

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

The characteristics of SN1 mechanism:

SN1 reaction is a nucleophilic substitution reaction.

Leaving group, a nucleophile, electrophile and a solvent are present

Two types of enantiomers can be formed in the reaction depending on the preference of the nucleophile.

The first step is the slowest because a bond is being broken.

SN1 reaction involves two steps and occurs fastest with tertiary alkyl halides

Therefore, the correct option is option A.

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Answer:

Acanthite. MFCD00003406

Explanation:

Answer:

3 pieces of lunch-meat and 2 slices of cheese

Explanation:

You have enough bread to make 3 sandwiches

You have enough lunch-meat to make 4 sandwiches

You have enough cheese to make 5 sandwiches

In all you have enough material to make 3 sandwiches

so if you subtract three from each number above you will have no bread, enough lunch-meat to make one sandwich and enough cheese to make two sandwiches

luch-meat for one sandwich is: 3 pieces

Cheese for two sandwiches is:  2 pieces

Answer:

0.517

Explanation:

HCN + NaOH → NaCN + H2O [balanced as written]

(35.4 mL) x (0.268 M NaOH) x (1 mol HCN / 1 mol NaOH) / (18.35 mL HCN) = 0.517 M HCN

Answer: 0.517

Explanation:

Explanation:

Entropy of a reaction ΔS∘rxn is the degree of disoderliness in a system. Gases generally have a higher degree of disorder compared to liquids. Hence for the reaction 2H2(g)+O2(g) ⟶ 2H2O(l), the entropy decreases sice the reactants are in the gaseous state and the products is in the liquid state of matter

Explanation:

6.02×1023 culture atoms have a mass of 63.5g. 12.0g. c +23.0g O2__44.0g CO2.(12.0+16.0+16.0=44.0g).1 mol 1 mol. 1 mol number molecules weight

The number of molecules in one mole of carbon dioxide is 6.02 × 10²³. Therefore, the number of moles of carbon dioxide which contains 4.11 × 10²³ molecules is 0.68.

The number of atoms that constitutes one mole of a substance is called Avogadro number. It is equal to  6.02 × 10²³. Thus, one mole of every elements contains Avogadro number of atoms.

Similarly, one mole of a compound contains  6.02 × 10²³ number of molecules. Thus, one mole of carbon dioxide contains these much molecules.

Given the number of molecules of carbon dioxide = 4.11 × 10²³

Then, no.of moles = number of molecules/ Avogadro number.

no.of moles = 4.11 × 10²³ /6.022 × 10²³  = 0.68.

Therefore, the number of moles of CO₂ that contains 4.11 × 10²³  molecules is 0.68.

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Answer:

Check the explanation

Explanation:

Sample volume V= 10 mL/min x 17 h x 60 min/h / 1000 mL/L = 10.2 L

The concentration is increased

             10200 mL (sample volum) / 10 mL (eluted sample) = 1020 times.

57x10-9 M / 1020 = 5.6x10-12 M    

1.5 M HNO3 will contain ≤ 2ppm x (1.5M/15.7M ) ≤ 0.190 ppm ≤ 190 ppb

Ignoring this is reagent impurity and calculating for sea water

≤ 190 ppb /1020 = 0.186 ppb = 0.186 x 10-9g/mL = 0.186 x 10-6g/L =

0.186 x 10-6g/L / 56 g/mol = 0.003 x10-6 M = 3 nM

Answer:

Endothermic. The energy is flowing into the molecules causing them to break apart and the ice pop change state.

Answer:

Yes, an autumn day isn’t cold enough to keep an ice pop at freezing temperatures.

Answer:

[tex]Q=2091J=2.091kJ[/tex]

Explanation:

Hello,

In this case, the formula we use to compute the heat Q by increasing the temperature, in terms of the mass and the heat capacity is:

[tex]Q=mCp(T_2-T_1)[/tex]

Titanium's heat capacity is 0.544284 J/g°C, thus, the for such temperature increase, the heat results positive as shown below:

[tex]Q=22.6g*0.544284\frac{J}{g^oC}*(1590^oC-1420^oC) \\\\Q=2091J=2.091kJ[/tex]

Best regards.

Answer:

3 half-lives

Explanation:

The half-life is the time that it takes to a radioactive element to decay to half of its initial amount.

Let's suppose we start with 64 g of the radioactive element.

Answer:

A) An element with the valence electron configuration 5s¹ would form a monatomic ion with a charge of +1. In order to form this ion, the element will lose electron(s) from/into the 5s subshell(s).

B) An element with the valence electron configuration 2s²2p⁴ would form a monatomic ion with a charge of +1. In order to form this ion, the element will lose electron(s) from/into the 2p (2pₓ specifically) subshell(s).

Explanation:

The secret to this task is to follow those rules for the stability of electronic structures of elements. The rules include

- Electrons are filled firstly into shells or subshells of lower energies first.

- While filling electronic structure or writing electronic structures for elements/ions, electrons are fed singly to the suborbital before pairing occurs, this is because the totally paired up electrons of a suborbital are more stable than the totally unpaired electrons of the same suborbital which is now in turn more stable than the combination of paired and unpaired electrons in the suborbitals.

A) For an element with its valence electron on 5s¹, this means that there is one valence electron on this atom's outermost shell and outermost suborbitals. So, to form a monoatomic ion, it would take between losing and gaining an electron. Gaining an electron leads to a 5s², which indicates empty 5p orbitals too and is therefore less stable than losing an electron which would lead to the loss of the shell 5 and focus on a completely filled 4-shell.

So, losing the electron from the 5s suborbital to become a monotonic ion makes it acquire a charge of +1.

B) Just like the explanation in (A), to form a monoatomic ion would require a loss or gain of an electron. With valence electrons 2s²2p⁴, gaining an electron would have led to a 2s²2p⁵ and a further breakdown as 2s²2pₓ²2pᵧ²2pz¹ which has unpaired and paired electrons in the 2p suborbital. This is evidently less stable than if an electron was lost, the valence electrons are 2s²2p³ and they are positioned in a totally unpaired fashion in the 2p suborbital as 2s²2pₓ¹2pᵧ¹2pz¹.

Hence, the more stable alternative is more likely to occur and the electron is lost from the 2pₓ suborbital to make the monoatomic ion of the element acquire a +1 charge status too because of lost electron too.

Hope this Helps!!!

The octet rule states that the atoms of the elements bond to each other in an attempt to complete their valence shell with eight electrons. In other words, the atoms will tend to give up or share electrons to complete eight electrons in the valence shell through an ionic, covalent or metallic bond.

In other words, the goal is to have the closest noble gas electron configuration, thus having the last complete electron shell and acquiring stability.

So, in this case, to comply with the octet rule:

A. An element with the valence electron configuration 5s¹ would form a monatomic ion with a charge of +1. In order to form this ion, the element will lose one electron from the 5s subshell.

For an element with its valence electron at 5s¹, this means that there is one valence electron in the outermost shell of this atom and in the outermost suborbitals. To form a monatomic ion, it would be necessary between losing or gaining an electron and that ion is stable. It takes less energy to lose the electron of the suborbital 5s and acquire a charge of of +1, than to acquire an electron, because it forms the 5s² suborbital, which indicates empty 5p orbitals too and is therefore less stable.

Also, in this way, the octet rule is fulfilled.

B. An element with the valence electron configuration 2s²2p⁴ would form a monatomic ion with a charge of -2. In order to form this ion, the element will gain two electron into the 2p subshell(s).

After gain two electron the atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas (2s²2p⁶). In this way, the octet rule is fulfilled and the ion is stable.

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