Can you please answer Question 9 please

Answer:

pOH = -log[OH-]

Explanation:

Hello,

To calculate the pH or pOH of a substance, we relate it the negative logarithm of either the H+ or OH- concentration.

pOH is used to find the alkalinity of a solution my measuring the concentration of the hydroxide ion [OH-]. Solutions having a pOH value that is greater than 7 are said to be acidic while solutions with value less than 7 are alkaline.

pH = -log[H+]

While

pOH = -log[OH-]

Note: the pOH value of a solution depends on the concentration of the hydroxide ion in the solution.

Explanation:

it's one mole because the atomic mass is treated as molar mass and the atomic mass of strontium is 87.62 grams/mol

Answer: His and Lys are deprotonated but Asp will be protonated.

Explanation:

As the pH is given as 7.4 and pK of His is given as 6.00. There will occur a positive charge on His when it's pH < pK therefore, it is neutral at the given pH.

As the pK value of Lys is 10.53 that is greater than the pH of 7.40. Therefore, charge on Lys is positive.

As the pK value of Asp is 3.65 which is less than the pH value of 7.40. Hence, Asp has a negative charge.

Therefore, we can conclude that His and Lys are deprotonated but Asp will be protonated.

Answer: A. enables equilibrium to be reached more quickly..

Explanation:

The catalyst can be define as an important ingredient may be a protein in the form of enzyme that is used to speed up the rate of the chemical reaction. The catalyst cause a transformational change in the substrate to produce product. The catalyst do not get consumed in the reaction. In the availability of the catalyst, the forward and reverse rates of the reactions will speed up this will allow the equilibrium to reach faster.

Answer:

Boiling point of the solution is 82.3°C

Explanation:

Boiling point elevation is defined as the increasing of a boiling point of a substance by the addition of a solute. The formula is:

ΔT = K×m×i

Where ΔT is change in temperature (Final T - 80.1°C), K is boiling point elevation constant (2.53°C/m), m is molality of the solution (moles of naphthalene / kg of benzene) and i is Van't Hoff factor (1 for Naphthalene)

Moles of 70.6g of naphthalene are:

70.6g × (1mol / 128.16g) = 0.5509 moles

Kg of 722mL of benzene are:

722mL × (0.877g / mL) × (1kg / 1000g) = 0.633kg of benzene

Replacing in boiling point elevation formula:

(T - 80.1°C) = 2.53°C/m×(0.5509mol / 0.633kg)×1

T - 80.1°C = 2.2°C

T = 80.1°C + 2.2°C

T = 82.3°C

The boiling point of the solution is 82.21°C.

Number of moles of solute = 70.6 g/128.16 g/mol = 0.55 moles

Mass of solvent= density of solvent× volume of solvent

= 722 mL × 0.877 g/mL = 633.2 g or 0.6332 Kg

Molality of the solution = 0.55 moles/0.6332 Kg = 0.869 m

We know that;

ΔT = K m i

ΔT = Boiling point depression

K = Boiling point constant

m = molality of solution

i = Van't Hoff factor

ΔT =  2.53°C/m × 0.869 m × 1

ΔT = 2.2°C

Recall that;

ΔT = Boiling point of solution-  Boiling point of pure solvent

Boiling point of solution = Boiling point of pure solvent + ΔT

Boiling point of solution =  80.1°C + 2.2°C

Boiling point of solution = 82.21°C

Learn more: https://brainly.com/question/2510654

Answer:

Molar Mass = 171.6 g/mol

Explanation:

Here we can use the equation PV = nRT, where n could stand for m / M, considering M = Molar Mass. Now we can rearrange this equation to isolate M, as we have to determine the " molar mass " of this vapor,

PV = ( m / M )RT,

density = mass / volume = PM / RT -

M = dRT / P

First convert celcius to kelvins and torr to " standard atmosphere " before plugging in the known values,

13 C = 286 K,

741 torr = 0.975 atm -

__________________________________________

M = (7.125)(0.0821) (286) / 0.975

M = 171.6 g /mol

Answer:

= 4 * 10-8    = 400 Angstrom

Explanation:

EF = 5 eV, K = 4.29 x 102 J/(s m K), and Cvel = 1% of the lattice heat capacity

K= 1/3 (Cv)*v*l

v is fermi velocity which is equal to [tex]v = (2E_f/m)^{0.5}[/tex]

after putting mass of electron as [tex]9.1 * 10^{-31}kg[/tex] and [tex]E_f = 5 eV[/tex] we get [tex]v= 1.33 * 10^6 m/s[/tex]

[tex]C_v[/tex] is 1% of lattice heat capacity

Heat Capacity of Aluminium is [tex]0.897 J g^{-1}K^-1[/tex]

Density = [tex]2.6989 g \ cm^{-3}[/tex]

For  lattice heat capacity you need to use the heat capacity for alimunium given  and then multiply with density to get per unit volume term

Heat Capacity per unit volume =   [tex]0.897 J g^{-1}K^-1[/tex] * [tex]2.6989 g \ cm^{-3}[/tex]

[tex]= 2.42 J K^{-1} cm^{-3} \\\\= 2.42* 10^6 J K^{-1} m^{-3}[/tex]

Cv = 1% of heat capacity per unit volume

[tex]=0.01 * 2.42* 10^8 J K^{-1} m^{-3} \\\\= 2.42* 10^4 J K^{-1} m^{-3}[/tex]

Putting values in this equation K= 1/3 (Cv)*v*l

[tex]l = 3K/(C_v * v )\\\\ = 3 * 4.29 * 10^2 / (2.42* 10^4 * 1.33 * 10^6 )[/tex]

[tex]= 4 * 10^{-8 }[/tex]

  = 400 Angstrom

Answer:

a network of buoys.

Explanation:

It is operated by noaa. The buoys transmit some of the data on a daily basis to NOAA through a satellite in space.

Answer:

1.5x10¯⁴Kg

Explanation:

Data obtained from the question include the following:

Volume = 0.1642mL = 0.1642cm³

Density = 0.917g/cm³

Mass =.?

The Density of a substance is simply defined as the mass per unit volume of the substance. Mathematically, it is represented as:

Density = Mass /volume

With the above formula, we can calculate the mass of the ice as follow:

0.917 = Mass / 0.1642

Cross multiply

Mass = 0.917 x 0.1642

Mass = 0.151g

Finally, we shall convert 0.1506g to kg. This is illustrated below:

1000g = 1k

Therefore, 0.151g = 0.151/1000 = 1.5x10¯⁴Kg

Answer:

1.77 atm

Explanation:

We have to check the values that gives the problem:

V= 70 L

mass =354.5 g

Molas weight= 70.9 g/mol

T=30 ºC

P= ?

We can find the moles of chlorine if we use the molar weight:

[tex]354.5g~\frac{1~mol}{70.9~g}[/tex]

[tex]5~mol[/tex]

Now, we have the moles, volume, temperature therefore we can use the ideal gas equation:

[tex]P*V=n*R*T[/tex]

We know the R value:

[tex]0.082\frac{atm*L}{mol*K}[/tex]

We have “K” units for the temperature, so we need to do the conversion:

[tex]30+273.15=303.15~K[/tex]

With all the data we can plug the values into the equation:

[tex]P*70L=5mol*303.15K*0.082\frac{atm*L}{mol*K} [/tex]

[tex]P=\frac{5mol*303.15K*0.082\frac{atm*L}{mol*K}}{70L}[/tex]

[tex]P=1.77~atm [/tex]

I hope it helps!

Answer: Water must be present for this reaction to occur.

Explanation:

Decomposition reactions require breaking of bonds which require energy and thus all of the decomposition reactions are endothermic reactions.

The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) whereas liquids are represented by (l) and gases are represented by (g) after their chemical formulas.

The balanced chemical reaction of [tex]CaCO_3[/tex] decomposition is:

[tex]CaCO_3(s)\rightarrow CaO(s)+CO_2(g)[/tex]

The decomposition of [tex]CaCO_3[/tex] requires heat and leads to formation of CaO as solid and [tex]CO_2[/tex] as product.

Thus the the statement that is not true is Water must be present for this reaction to occur.

Answer:

2NH4NO3->2N2+O2+4H2O

Explanation:

U have to ensure that they are equal both side s hope it helps

Answer: See below

Explanation:

To balance equations, you want to have the same amount of elements on the product and reactants side.

__Al+ __HCl→__AlCl₃+ __H₂

We see that there are 3 Cl on the products side and 1 on the reactants side, but there are 2 H on the product and 1 on reactant. To fulfill them both, let's put a 6 at HCl.

__Al+ 6HCl→__AlCl₃+ __H₂

Now that we have a 6 at HCl, we can fill in AlCl₃ and H₂.

__Al+ 6HCl→ 2AlCl₃+ 3H₂

All we have left is to fill in Al.

2Al+ 6HCl→ 2AlCl₃+ 3H₂

-----------------------------------------------------------------------------------------------------------------

__NaCl→ __Na+ __Cl₂

Since we have 2 Cl on the products, we must put 2 on the reactants.

2NaCl→ __Na+ 1Cl₂

With 2 NaCl, we can fill in Na.

2NaCl→ 2Na+ 1Cl₂

-----------------------------------------------------------------------------------------------------------------

__Na₂S+ __HCl→ __NaCl+ __H₂S

We see 2 Na on reactants, so we can put 2 on the products.

__Na₂S+ __HCl→ 2NaCl+ __H₂S

With 2 H and 2 Cl on the products, we can put a 2 at HCl.

1Na₂S+ 2HCl→ 2NaCl+ 1H₂S

Answer:

The reaction of FeBr3/Br2 with benzaldehyde will yield a major product in which the -Br is attached to the benzaldehyde at the meta position.

Explanation:

In chemistry, resonance is a way of describing bonding in certain molecules or ions by the combination of several contributing structures into a resonance hybrid in valence bond theory. Resonance structures often explain the formation of certain major and minor products in organic chemistry reactions.

Aromatic aldehydes and ketones undergo electrophilic substitution reactions such as nitration, sulphonation and halogenation. Since the aldehydic group (-CHO) and ketonic group (-COR or -COAr) are electron-withdrawing, they are deactivating and m-directing.

In benzaldehyde, the ring becomes deactivated at ortho & para positions due to an electron withdrawing aldehyde group. Hence electrophilic substitution is favored at Meta position.

This implies that the reaction of FeBr3/Br2 with benzaldehyde will yield a major product in which the -Br is attached to the benzaldehyde at the meta position.

Answer:24 kilometers

Explanation:Density divided by time

Answer:

0.00316

Explanation:

You have to use the following equation:

[tex]pH=-log[H^+][/tex]

You are given the pH and need to find the concentration of H+.  Plug in the given components and solve.

[tex]2.5=-log[H^+]\\H^+ = 10^{-2.5}\\H^+=0.00316[/tex]

The concentration of H is 0.00316.

Explanation:

The number of nitrogen atoms in one mole of nitrogen gas are 6.02214179×1023 nitrogen atoms.

Hope this helps...

Answer:

The correct answer is 27.22 mg.

Explanation:

Based on the given information, the temperature of the water given is 22.4 degree C or 22.4 + 273 = 295.4 K

The volume of the gathered hydrogen is 37.1 ml or 0.0371 L

The pressure mentioned in the lab room is 29.18 in Hg or 29.18 × 2.54 = 74.1172 cm Hg.

18.4 cm is the difference given in the water level between the burette and the beaker, so the pressure is,

74.1172 cm - 18.4 cm = 55.7172 cm Hg or 557.172 mmHg

760 mmHg is equal to 1 atm, therefore, 557.172 mmHg will be equal to,

557.172 mm Hg / 760 mm Hg × 1 atm = 0.733 atm

The moles of hydrogen gas can be calculated by using the ideal gas equation, that is, PV = nRT

n = PV / RT

Putting the values we get,

n = 0.733 atm × 0.0371 L / 0.0821 atm L mol⁻¹ K⁻¹ × 295.4 K

n = 0.00112 mol

Let us consider the equation,

2 HCl + Mg ⇒ H₂ + MgCl₂

By seeing the reaction it is clear that for the generation of 1 mole of hydrogen gas, 1 mole of magnesium is needed.

The moles of magnesium is 0.00112 moles and the molecular mass of magnesium is 24.305 gram per mol

The mass of magnesium ribbon can be determined by using the formula, mass = mole × molecular mass

mass = 0.00112 mole × 24.305 g/mol

mass = 0.02722 grams or 27.22 mg.

Explanation:

faster and the substance will be a gas.

According to the forces of attraction and principles of phase change the substance molecules will move faster and the substance will be a gas.

Forces of attraction  is a force by which atoms in a molecule  combine. it is basically an attractive force in nature.  It can act between an ion  and an atom as well.It varies for different states  of matter that is solids, liquids and gases.

The forces of attraction are maximum in solids as  the molecules present in solid are tightly held while it is minimum in gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.

The physical properties such as melting point, boiling point, density  are all dependent on forces of attraction which exists in the substances.

Learn more about forces of attraction,here:

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Explanation:

a) E = P × t

E = 750 × 1 s = 750 J

b) E = P × t

E = 750 × 3s = 2250 J

c) E = P × t

1500 = 750 × t

t = 1500/750

t = 2 s

Answer: -100 kJ

Explanation:

Heat of reaction or enthalpy of the reaction is the energy released or absorbed during the course of the reaction.

Heat of reaction is represented by the symbol [tex]\Delta H[/tex].

[tex]\Delta H=H_{products}-H_{reactants}[/tex]

[tex]\Delta H[/tex] = enthalpy of reaction = ?

[tex]H_{products}[/tex] = enthalpy of products = 0 kJ

[tex]H_{reactants}[/tex] = enthalpy of reactants = 100 kJ

[tex]\Delta H=0kJ-100kJ[/tex]

[tex]\Delta H=-100kJ[/tex]

Thus the ΔH for the reaction is -100kJ

Answer:

because of their chemical defenses. (more info below)

Explanation:

Skunks have relatively few natural predators of their species. This is a testament to the effectiveness of their chemical defenses. Unfortunately, several skunks are killed when they cross busy roads at night. Deterrence is also not effective against a predator with a poor sense of smell like a Great Horned Owl.

hope I helped!

Answer:

2.25 moles ≈ 2.3 moles

Explanation:

Full Question:

Acetylene C2H2 gas is often used in welding torches because of the very high heat produced when it reacts with oxygen O2 gas, producing carbon dioxide gas and water vapor. Calculate the moles of oxygen needed to produce 1.5mol of water. Be sure your answer has a unit symbol, if necessary, and round it to significant digits.

First off, let's put the equation of the reaction sown;

C2H2 + O2 → H2O + CO2

Upon balancing, we have;

2C2H2 + 3O2 → 2H2O + 4CO2

So from the equation;

3 mole of oxygen is required in order to produce 2 mole of water vapour.

The question asks to calculate moles of oxygen needed to produce 1.5mol of water

This leads us to;

3 moles = 2 moles

x moles = 1.5 moles

x = ( 1.5 * 3 ) / 2

x = 4.5 / 2 = 2.25 moles ≈ 2.3 moles

Answer:

H20; exothermic

Explanation:

A fuel cell is a device that converts chemical potential energy (energy stored in molecular bonds) into electrical energy. A PEM (Proton Exchange Membrane) cell uses hydrogen gas (H2) and oxygen gas (O2) as fuel. The products of the reaction in the cell are water, electricity, and heat.

Answer:

The reaction mentioned in the question is:  

CO (g) + Cl₂ (g) ⇔ COCl₂ (g), the equilibrium constant or Kc will be 77.5 at 600 K. In the given mixture, the moles of CO given is 4.24 × 10⁻² moles, the moles of Cl₂ given is 4.48 × 10⁻² moles, and the moles of COCl₂ given is 0.114 moles. The volume of the container is 1.00 L.  

The concentration or Molarity can be determined by using the formula, concentration (M) = mole/volume (L),  

The molarity of CO = 4.24 × 10⁻² moles / 1.00 L = 4.24 × 10⁻² M

The molarity of Cl₂ = 4.48 × 10⁻² moles / 1.00 L = 4.48 10⁻² M

The molarity of COCl₂ = 0.114 moles / 1.00 L = 0.114 M

The reaction quotient or Qc,  

Qc = [COCl2]/[CO][Cl2]  

Qc = 0.114 / 4.24 × 10⁻² × 4.48 × 10⁻²

Qc = 60.03

Thus, Qc is less than Kc. Hence, the reaction will proceed in forward direction so that equilibrium can be attained, that is, until Qc becomes equal to Kc.  

Therefore, the product (COCl₂) will be produced, and the reactants CO and Cl₂ will get consumed.  

1. The given statement is true.  

2. The given statement is true.  

3. The given statement is false. In order to reach equilibrium, the reactants must be consumed.  

4. The given statement is true.  

5. The given statement is false, that is Qc is not equal to Kc.  

Answer:

1.092 moles of Mg

Explanation:

Avogadro's number is a constant that define the number of particles (Such as atoms, molecules, electrons, ions) that you have in 1 mole. That means in 1 mole you have 6.022x10²³ of the particle in question.

If you have 6.578x10²³ atoms of Mg -and 1 mole of Mg contains 6.022x10²³ atoms of Mg-:

6.578x10²³ atoms of Mg × (1 mole Mg / 6.022x10²³ atoms of Mg) =

Answer:

Oxidation state shows the total number of electrons which have been removed from an element (a positive oxidation state) or added to an element (a negative oxidation state) to get to its present state

Answer:

(a) [tex]CH_3COOH \rightleftharpoons CH_3COO^-+ H^+[/tex]: reverse reaction is favored.

(b) [tex]AgCl \rightleftharpoons Ag^+ + Cl^-[/tex]: reverse reaction is favored.

(c) [tex]Al(OH)_3 \rightleftharpoons Al^{3+} + 3OH^-[/tex]: reverse reaction is favored.

(d) [tex]A+B\rightleftharpoons C[/tex]: forward reaction is favored.

Explanation:

Hello,

(a) [tex]CH_3COOH \rightleftharpoons CH_3COO^-+ H^+[/tex]:

In this case, since the Ka is lower than 1, we infer the reverse reaction is favored since the reactant (acetic acid) will tend to have a higher concentration.

(b) [tex]AgCl \rightleftharpoons Ag^+ + Cl^-[/tex]:

In this case, since the Ka is lower than 1, we infer the reverse reaction is favored since the reactant (silver chloride) will tend to have a higher concentration.

(c) [tex]Al(OH)_3 \rightleftharpoons Al^{3+} + 3OH^-[/tex]

In this case, since the Ka is lower than 1, we infer the reverse reaction is favored since the reactant (aluminium hydroxide) will tend to have a higher concentration.

(d) [tex]A+B\rightleftharpoons C[/tex]

In this case, since the Ka is greater than 1, we infer the forward reaction is favored since the product (C) will tend to have a higher concentration.

Regards.

Answer:

To live in the White House

Explanation:

While George Washington was in office, the white house was still in the stages of being built. Hence John Adams was the first president to reside and live in the White house.

Answer:

It's B to live in the white house.

Explanation: