Is it true or false?

Answer:

A. The Swallowing reflex

Explanation:

Dysphagia Is a a condition that makes swallowing difficult.

Answer:

Disulfate Ion {2-} Name: Disulfate Ion {2-} Formula: S2O7.

Explanation:

HOPE THIS HELPED :)

Answer:

Pyrosulfate

In chemistry, disulfate or pyrosulfate is the anion with the molecular formula S₂O²⁻₇. Disulfate is the IUPAC name. It has a dichromate-like structure and can be visualised as two corner-sharing SO₄ tetrahedra, with a bridging oxygen atom. In this anion, sulfur has an oxidation state of +6. Disulfate is the conjugate base of the hydrogen disulfate ion HS₂O⁻₇, which in turn is the conjugate base of disulfuric acid.

Explanation:

In chemistry, disulfate or pyrosulfate is the anion with the molecular formula S 2O2− 7. Disulfate is the IUPAC name. It has a dichromate -like structure and can be visualised as two corner-sharing SO 4 tetrahedra, with a bridging oxygen atom. In this anion, sulfur has an oxidation state of +6.

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:

Option C

Explanation:

A double displacement reaction is the one in which two chemical compounds having a cation and anion in each exchange their positive and negative ions thereby forming new compounds or products.

Here,

The first compound [tex]PbCl_2[/tex] has a positive ion [tex]Pb[/tex] and negative ion [tex]Cl^-[/tex]

Like wise the second compound [tex]Ag(NO_3)[/tex] has a positive ion [tex]Ag[/tex] and negative ion [tex]NO_3[/tex]

The new compounds will be formed when cation of one compound attaches with the anion of other compound. Hence the new compounds are

[tex]Pb(NO_3)_2[/tex]

[tex]AgCl[/tex]

This is example of double displacement reaction.

Option C is correct

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:

BaSO4(aq) + TiO(aq) —> BaO(aq) + TiSO4(aq)

Explanation

The equation for the reaction between barium sulfate and titanium (II) oxide is given below:

BaSO4 + TiO —>

In solution, the reactants will dissociates as follow:

BaSO4(aq) —> Ba^2+(aq) + SO4^2-(aq)

TiO(aq) —> Ti^2+(aq) + O^2-(aq)

The double displacement reaction will occur as follow:

Ba^2+(aq) + SO4^2-(aq) + Ti^2+(aq) + O^2-(aq) —> Ba^2+O^2-(aq) + Ti^2+SO4^2-(aq)

We can see that a double displacement reaction occurred as there is a double exchange of ions in the solution. The elemental equation is given below:

BaSO4(aq) + TiO(aq) —> BaO(aq) + TiSO4(aq)

Answer:

the motion of gravity

Explanation:

Answer:

its c

Explanation

advhuosijoklxcmnjdabsuhggggabciaciudeifweingivg eygerigsygfe97rsghisdcvhbsduigwiugfu9uigdgiurfgyisdgfsdgfegiygewifgsdygfewusgfuyesigf7wgfiesgfiusgdfies

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:

0.001 M

Explanation:

The pH scale is used to determine the acidity or basicity of a solution.

The pH is related to the concentration of hydrogen ions through the following expression.

pH = -log [H⁺]

[H⁺] = antilog -pH = antilog - 3 = 0.001 M

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:

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:

See explaination

Explanation:

1. The addition of group 3A elements to group 4A semiconductors decreases the conductivity of the group 4A semiconductors: Wrong

The addition of 3A group elements inreases the conductivity and make them extrinsic semiconductors( p-type)

2. The conductivity of semiconductors can be increased by the doping process.: Correct

3.As the temperature increases, the conductivity of semiconductors decreases.. wrong

As the temperature increases, the conductivity of semiconductors increases.

4. The addition of group 5A elements to group 4A semiconductors increases the conductivity of the group 4A semiconductors: Correct : They will create n-type semicoductor.

5.Holes are charge carriers in p-type semiconductors: Correct

6. Electrons are charge carriers in n-type semiconductors: Correct

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:

THE NUMBER OF MOLES OF HELIUM NEEDED TO FILL A BALLOON AT A VOLUME OF 4.9 L AT 296 K AND 0.78 atm IS 0.00338 moles.

Explanation:

The number of moles is calculated using

PV = nRT

P = Pressure = 0.78 atm

V = volume = 4.9 L

R = gas constant = 0.082 Latm/molK

T = temperature = 296 K

n= number of moles

Substituting theses values and sloving for n, we obtain;

n = PV / RT

n = 0.78 * 4.9 / 0.082 * 296

n = 3.822 / 24.272

n = 0.00338 moles.

So therefore, the number of moles is 0.00338 moles.

Answer:

The number of moles of helium needed is 0.157 moles helium

Explanation:

Step 1: Data given

Volume of the balloon = 4.9 L

Temperature= 296 K

Pressure = 0.78 atm

Step 2: Calculate moles of helium gas

p*V = n*R*T

⇒with p = the pressure = 0.78 atm

⇒with V = the volume = 4.9 L

⇒with n = the number of moles of the helium gas = TO BE DETERMINED

⇒with R = the gas constant = 0.08206 L*atm/mol* K

with T = the temperature = 296 K

n = (p*V) / (R*T)

n = (0.78 atm* 4.9 L) / (0.08206 L*atm/mol*K * 296 K)

n = 0.157 moles of helium

The number of moles of helium needed is 0.157 moles helium

Answer:

C)

Explanation:

JUST DID IT

Answer:

A D E

Explanation:

just did it

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:

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:

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:

IN the description

Explanation:

The generally accepted parts of modern cell theory include:

All known living things are made up of one or more cells. All living cells arise from pre-existing cells by division. The cell is the fundamental unit of structure and function in all living organisms.

Answer:

Sample Response: The first component of the cell theory says that all living things are made of cells. The second component of the cell theory states that cells are the basic structure and function of living things. The last component of the cell theory says that cells come from other cells.

Answer:

1.

[tex]A=69.8\frac{bar}{m^6}\\\\ B=0.00302bar*m^6[/tex]

2. [tex]W=-8.2kPa[/tex]

Explanation:

Hello,

1. In this case, for the given p-V equation, one could use the two states to form a 2x2 linear system of equations in terms of A and B:

[tex]\left \{ {{0.1^2A+0.1^{-2}B=1} \atop {0.04^2A+0.04^{-2}B=2}} \right.[/tex]

[tex]\left \{ {{0.01A+100B=1} \atop {0.0016A+625B=2}} \right[/tex]

Whose solution by any method for solving 2x2 linear system of equations (elimination, reduction or substitution) is:

[tex]A=69.8\frac{bar}{m^6}\\\\ B=0.00302bar*m^6[/tex]

2. Now, for us to compute the work, we must first compute n, as the power relating the pressure and volume for this process:

[tex]P_1V_1^n=P_2V_2^n\\\\\frac{P_1}{P_2}=(\frac{V_2}{V_1} )^n\\\\\frac{1bar}{2bar}= (\frac{0.04m^3}{0.1m^3} )^n\\\\0.5=0.4^n\\\\n=\frac{ln(0.5)}{ln(0.4)} =0.7565[/tex]

Now, we compute the work:

[tex]W=\frac{P_2V_2-P_1V_1}{1-n} =\frac{2bar*0.04m^3-1bar*0.1m^3}{1-0.7565} \\\\W=-0.082bar*m^3*\frac{1x10^2kPa}{1bar}\\ \\W=-8.2kPa[/tex]

Regards.

Answer:

Explanation:

Hello!

a)

You have an integral membrane protein (Bacteriorhodopsin) that uses solar energy to pump protons out of the cell against its electrochemical gradient.

To calculate the energy needed by the protein to pump one molecule out of the cell you need to apply the free energy difference equation for a charged molecule:

ΔG= 2.303RTlog₁₀[tex](\frac{[H^+]out}{[H^+]in})[/tex]+zFΔV

Where

ΔG= free energy difference per molecule transferred from the inside to the outside

R= gas constant 8.315*10⁻³ kJ/mol

T= Temperature in Kelvin (273.15 + TºC)

z= Valency of the ion (ej Na⁺ is z= +1 and Cl⁻ is z= -1)

F= Faraday constant 96.5 kJ/V*mol

ΔV= membrane potential (Volts)

The information you have is:

Intracellular pH= 9.4

Extracellular pH= 6.4

ΔV= 120 mV

Temperature 27ºC

Using the values of pH you can calculate the intracellular and extracellular proton concentrations:

Remember the pH of a solution is calculated as pH=-log[H⁺] so if you reverse the logarithm, you'll find the concentration of protons:

b= logₐ C ⇒ C= aᵇ

[H⁺]intracelular= 10⁻⁹'⁴

[H⁺]extracelular= 10⁻⁶'⁴

Now you need to match the units of the temperature and electrical gradient to the ones in the equation:

The temperature needs to ve in Kelvin: T= 273.15 + 27ºC= 300.15K

The electrical gradients need to be in Volts: ΔV= 120 mV= 0.12V

Now you can replace the data in the formula and calculate how much energy is needed to pump one proton outside the cell:

ΔG= 2.303RTlog₁₀[tex](\frac{[H^+]out}{[H^+]in})[/tex]+zFΔV= 2.303*( 8.315*10⁻³ kJ/mol)*300.15K*log[tex](\frac{10^{-6.4}}{ 10^{-9.4}} )[/tex]+(+1)*96.5 kJ/V*mol*0.12V= 28.82 kJ/mol

It costs 28.82 kJ/mol to pump one mole of H⁺ outside the cell.

b)

To synthesize one molecule of ATP the ATP synthase uses the electrical gradient produced by the spontaneous pass of protons through the membrane. This process is called the proton-motive force.

The ATP synthase consists of two subunits F₀ and F₁ with a rotational motor mechanism that allows it to produce and release ATP.

F₁ has the subunits α, β, σ, γ, ε in charge of synthesizing ATP

F₀ is a proton pore, made of 3 subunits a, b and c. 6 subunits c make up the transmembrane ring in charge of rotation, this ring is connected to the subunits γ and ε. Each time a proton passes, it makes the ring rotate which makes the subunits γ rotate.

Each time the subunit γ rotates 360º, 3 ATP molecules are synthesized and freed. A full rotation of γ means that the c-ring also made a full rotation (for this you need one proton per subunit)

If the ring has 6 c-subunits and, then each ATP molecule needs 6/3= 2 protons to need to pass for each ATP molecule.

I hope this helps!

Answer:

[tex]M=1.1M[/tex]

Explanation:

Hello,

In this case, since we are mixing two NaOH solutions, the first step is to compute the total moles once the mixing is done, by using the volumes and concentrations of each solutions and subsequently adding them:

[tex]n_T=2.0L*0.60\frac{mol}{L}+495mL*\frac{1L}{1000mL}*3.0\frac{mol}{L}= 2.7molNaOH[/tex]

Next, we compute the total volume by adding the volume of each solution:

[tex]V_T=2.0L+495mL*\frac{1L}{1000mL}= 2.495L[/tex]

Finally, we compute the molarity of the resulting solution by the division between the total moles and the total volume:

[tex]M=\frac{2.7mol}{2.495L}\\ \\M=1.1M[/tex]

Best regards.

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:

The first thing you will need to do is find some information about your element. Go to the Periodic Table of Elements and click on your element. If it makes things easier, you can select your element from an alphabetical listing.

Number of Protons = Atomic Number

Number of Electrons = Number of Protons = Atomic Number

Number of Neutrons = Mass Number - Atomic Number

For krypton:

Number of Protons = Atomic Number = 36

Number of Electrons = Number of Protons = Atomic Number = 36

Number of Neutrons = Mass Number - Atomic Number = 84 - 36 = 48

Explanation:

hope this helps, have a good day :-)

Answer:

.It is easily synthesized from the reaction of propylene with sulfuric acid, followed by hydrolysis. Isopropyl alcohol (2-propanol) is made by indirect hydration of propylene (CH2CHCH3).… In some cases the hydration of propylene is carried out in one step, using water and a catalyst at high pressure.

Hope it'll help!

stay safe:)

Answer:

[tex]\Delta V = 234.736\,mL[/tex]

Explanation:

The quantity of moles of ethanol in the solution is:

[tex]n_{C_{2}H_{5}OH} = \left(\frac{597\,mL}{1000\,mL} \right)\cdot \left(8.35\,\frac{mol}{L} \right)[/tex]

[tex]n_{C_{2}H_{5}OH} = 4.985\,mol[/tex]

The mass and volume of ethanol in the solution are, respectively:

[tex]m_{C_{2}H_{5}OH} = (4.985\,mol)\cdot \left(46.07\,\frac{g}{mol} \right)[/tex]

[tex]m_{C_{2}H_{5}OH} = 229.658\,g[/tex]

[tex]V_{C_{2}H_{5}OH} = \frac{229.658\,g}{0.7893\,\frac{g}{mL} }[/tex]

[tex]V_{C_{2}H_{5}OH} = 290.964\,mL[/tex]

The difference between the total volume of water and ethanol mixed to prepare the solution and the actual volume of solution is:

[tex]\Delta V = (525\,mL+597\,mL) - (597\,mL + 290.964\,mL)[/tex]

[tex]\Delta V = 234.736\,mL[/tex]

The difference in volume between the total volume of water and ethanol is ΔV =234.736 mL.

The quantity of moles of ethanol in the solution is:

[tex]nC_2H_5OH=\frac{597mL}{1000mL} *8.35mol/L\\\\nC_2H_5OH=4.985 moles[/tex]

The mass and volume of ethanol in the solution are, respectively:

[tex]mC_2H_5OH=4.985moles*46.07g/mol\\\\mC_2H_5OH=229.685g[/tex]

[tex]VC_2H_5OH=\frac{229.685g}{0.7893g/mL} \\\\VC_2H_5OH=290.964mL[/tex]

The difference between the total volume of water and ethanol mixed to prepare the solution and the actual volume of solution is:

ΔV= (525mL+597mL)- (597mL + 290.964 mL)

ΔV= 234.736mL

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