an extra strength antacid tablet contains 750 mg of active ingredient, caco3. if it takes 22.25 ml of hcl to neutralize the tablet, how strong is the acid

Answer:

The total photons required = 5.19 × 10²⁸ photons

Explanation:

Given that:

the radiation wavelength λ= 12.5 cm = 0.125 m

Volume of the container = 0.250 L = 250 mL

The density of water = 1 g/mL

Density = mass /volume

Mass =  Volume ×  Density

Thus; the mass of the water =  250 mL ×  1 g/mL

the mass of the water = 250 g

the specific heat of water s = 4.18 J/g° C

the initial temperature [tex]T_1[/tex] = 20.0° C

the final temperature [tex]T_2[/tex] = 99° C

Change in temperature [tex]\Delta T[/tex] = (99-20)° C = 79 ° C

The heat q absorbed during the process = ms [tex]\Delta T[/tex]

The heat q absorbed during the process = 250 g × 4.18 J/g° C × 79° C

The heat q absorbed during the process = 82555 J

The energy of a photon can be represented by the equation :

= hc/λ

where;

h = planck's constant = [tex]6.626 \times 10^{-34} \ J.s[/tex]

c = velocity of light = [tex]3.0 \times 10^8 \ m/s[/tex]

=  [tex]\dfrac{6.626 \times 10^{-34} \times 3.0 \times 10^8}{0.125}[/tex]

= [tex]1.59024 \times 10^{-24}[/tex] J

The total photons required = Total heat energy/ Energy of a photon

The total photons required = [tex]\dfrac{82555 J}{1.59024 \times 10^{-24}J}[/tex]

The total photons required = 5.19 × 10²⁸ photons

Answer:

See explanation below

Explanation:

IUPAC came up with the idea of an unambiguous system of nomenclature for organic compounds. This unambiguous system relates the structure of a compound with its name. Thus, IUPAC has established a worldwide standard for the unambiguous naming of organic compounds. Scientists all over the world can now have a uniform system of nomenclature for compounds in order to facilitate easy communication of scientific information.

The systematic names of the following compounds listed in the question are shown below;

(R)-2- butyl bromide has the systematic name (R)-2-bromobutane

(S)-2-butyl bromide has the systematic name (S)-2-bromobutane

This unified system of nomenclature avoids the confusion created by the use of different trivial names in deferent localities and by various scientific academies. This is a major advantage of the systematic nomenclature.

The substance which gives more ions in ionization will be more conductive and those giving less ions will be less conducting. Here, glucose only give no ion in water thus, it has the lower conductivity.

Ionization is the process of dissociation of compounds into its constituent ions. For example, HCl when dissolved in water will give H+ and Cl- ions. Similarly HNO₃  gives H+ and NO₃- ions in ionization.

Water can easily dissolves the ionic compounds by forming hydrogen bonds with them and thus easily ionises them The ions formed are mobile and conduct electricity. The more the number of ions the higher the electrical conductivity.

CaCl₂ gives Ca²⁺ and two Cl- ions and NH₃ gives NH₄⁺ ions and CO₂ gives H+ ions by the formation of carbonic acid. Wheres, glucose does not give its ions and thus has lower conductivity for the solution.

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Answer:

Option B. 2096.1 K

Explanation:

Data obtained from the question include the following:

Enthalpy (H) = +1287 kJmol¯¹ = +1287000 Jmol¯¹

Entropy (S) = +614 JK¯¹mol¯¹

Temperature (T) =.?

Entropy is related to enthalphy and temperature by the following equation:

Change in entropy (ΔS) = change in enthalphy (ΔH) / Temperature (T)

ΔS = ΔH / T

With the above formula, we can obtain the temperature at which the reaction will be feasible as follow:

ΔS = ΔH / T

614 = 1287000/ T

Cross multiply

614 x T = 1287000

Divide both side by 614

T = 1287000/614

T = 2096.1 K

Therefore, the temperature at which the reaction will be feasible is 2096.1 K

Answer:

0.96 mol CO

Explanation:

We simply just use the reaction to help us find this:

[tex]1.2 mol C(\frac{4 mol CO}{5 mol C} )[/tex]

Multiply it out and we get 0.96 as our answer.

Answer:

1 mole of CaC₂ will produce 26g of C₂H₂ or 64.1g of CaC₂ will produce 26g of C₂H₂

Explanation:

Hello,

To solve this question, we'll require a balanced chemical equation of reaction between calcium carbide and water.

Equation of reaction

CaC₂ + 2H₂O → Ca(OH)₂ + C₂H₂

Molar mass of calcium carbide (CaC₂) = 64.1g/mol

Molar mass of water (H₂O) = 18g/mol

Molar mass of calcium hydroxide (Ca(OH)₂) = 74g/mol

Molar mass of ethyne (C₂H₂) = 26g/mol

From the equation of reaction, 1 mole of CaC₂ will produce 1 mole of C₂H₂

1 mole of CaC₂ = mass / molar mass

Mass = 1 × 64.1

Mass = 64.1g

1 mole of C₂H₂ = mass / molar mass

Mass = 1 × 26

Mass = 26g

Therefore, 1 mole of CaC₂ will produce 26g of C₂H₂

Note: this is a hypothetical calculation since we were not given the initial mass of CaC₂ that starts the reaction

Answer:

It may be a hemorrhagic stroke because of the patient's history.

Explanation:

Uncontrolled hypertension could generate a hemorrhagic stroke within the brain generating the sign of progressive dementia, this is due to the vessel breaking due to the excess pressure of the internal light, it breaks and releases or extravases all the bloody contents to the brain

The difficulty of this is that the brain is the one that yields to a force in relation to the skull, that is why it is compressible against hemorrhage generating these signs as progressive dementia and could even be death or vegetative state

A nonmetal and a nonmetal will make molecular compounds like H2O and CO2

Answer:

The new mass/volume percent is 2.0% (m/v)

Explanation:

Dilution is a procedure by which the concentration of a solution is decreased, generally with the addition of a diluent. In other words, dilution is a process in which a concentrated solution is always started, to which a greater volume of solvent is added, causing the concentration and volume of the resulting solution to change. But the amount of solute used to prepare the initial solution remains the same.

The calculation of a dilution is made by:

Cinitial. Vinitial = Cfinal. Vfinal

where C indicates concentration and V indicates volume.

In this case:

Replacing:

6.0% (m/v) * 110 mL= Cfinal* 330 mL

Solving:

[tex]Cfinal=\frac{ 6.0 (m/v)*110 mL}{330 mL}[/tex]

Cfinal=   2.0% (m/v)

The new mass/volume percent is 2.0% (m/v)

Answer:

2.17x10⁻¹⁰ = Kb1

1.69x10⁻¹³ = Kb2

Explanation:

Oxalic acid, C₂O₄H₂, has two intercambiable protons, its equilibriums are:

C₂O₄H₂ ⇄ C₂O₄H⁻ + H⁺ Ka1 = 5.9x10⁻²

C₂O₄H⁻ ⇄ C₂O₄²⁻ + H⁺ Ka2 = 4.6x10⁻⁵

Oxalate ion, C₂O₄²⁻, has as equilibriums:

C₂O₄²⁻ + H₂O ⇄ C₂O₄H⁻ + OH⁻ Kb1

C₂O₄H⁻ + H₂O ⇄ C₂O₄H₂ + OH⁻ Kb2

Also, you can know: KaₓKb = Kw

Where Kw is 1x10⁻¹⁴

Thus:

Kw = Kb2ₓKa1

1x10⁻¹⁴ =Kb2ₓ4.6x10⁻⁵

And:

Kw = Kb1ₓKa2

1x10⁻¹⁴ =Kb1ₓ5.9x10⁻²

That is because the inverse reaction of, for example, Ka1:

C₂O₄H⁻ + H⁺ ⇄ C₂O₄H₂ K = 1 / Ka1

+ H₂O ⇄ H⁺ + OH⁻ K = Kw = 1x10⁻¹⁴

=

C₂O₄H⁻ + H₂O ⇄ C₂O₄H₂ + OH⁻ Kb2 = Kw × 1/Ka1

Answer:

0.774g of ethanol

0.970mL of ethanol

Explanation:

Molality is an unit of concentration defined as the ratio between moles of solute and kg of solvent.

In the problem, you need to prepare a 1.2m solution of ethanol (Solute) in t-butanol (solvent).

14.0g of butanol are 0.014kg and as you want to prepare the 1.2m solution, you need to add:

0.014kg × (1.2moles / kg) = 0.0168 moles of solute = Moles of ethanol

To convert moles of ethanol to mass you require molar mass (Molar mass ethanol, C₂H₅OH = 46.07g/mol). Thus, mass of 0.0168 moles are:

0.0168moles Ethanol ₓ (46.07g / mol) =

And to convert mass in g to mL you require density of the substance (Density of ethanol = 0.798g/mL):

0.774g ₓ (1mL / 0.798g) =

Answer:

HCl

Explanation:

Choices:

CO: 28.01g/mol

NO₂: 46g/mol

CH₄: 16.04g/mol

HCl: 36.4g/mol

CO₂: 44.01g/mol

It is possible to identify a substance finding its molar mass (That is, the ratio between its mass in grams and its moles). It is possible to find the moles of the gas using general ideal gas law:

PV = nRT

Where P is pressure of gas 0.764atm; V its volume, 0.279L; n moles; R gas constant: 0.082atmL/molK and T its absolute temperature, 295.85K (22.7°C + 273.15).

Replacing:

PV = nRT

PV / RT = n

0.764atm*0.279L / 0.082atmL/molKₓ295.85K = n

8.786x10⁻³ = moles of the gas

As the mass of the gas is 0.320g; its molar mass is:

0.320g / 8.786x10⁻³moles = 36.4 g/mol

Based in the group of answer choices, the identity of the gas is:

Molar mass of substance is the mass of one mole of substance. The gas is identified as HCl as it has 36.4 g/mol of molar mass.

The substance can be identified from its molar mass. The formula to calculate the molar mass is

[tex]\bold {m = \dfrac w{n}}[/tex]

Where,

n - number of moles

w - given mass of the substance  

The number of moles can be calculated by the using  ideal gas law

PV = nRT

[tex]\bold {n = \dfrac {PV }{ RT }}[/tex]  

Where

P - pressure of gas 0.764 atm;

V its volume, 0.279 L;

n moles;

R gas constant: 0.082atmL/molK

T its absolute temperature, 295.85 K (22.7°C + 273.15).  

Put the values in the formula,  

[tex]\bold {n = \dfrac {0.764\ atm \times , 0.279 }{ 0.082 \times 295.85 }}\\\\\bold {n =8.786x10^-^3}[/tex]  

Now, put the values in the molar mass formula,

[tex]\bold {m = \dfrac {0.320g}{ 8.786x10^-^3} = 36.4\ g/mol}[/tex]

Therefore, the gas is identified as HCl as it has 36.4 g/mol of molar mass.

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Answer:

3.01 × 10²³ molecules

Explanation:

Step 1: Given data

Moles of water (n): 0.500 mol

Step 2: Calculate the molecules of water present in 0.500 moles of water

In order to perform this calculation, we will use the Avogadro's number: in 1 mole of water there are 6.02 × 10²³ molecules of water.

0.500 mol × (6.02 × 10²³ molecules/1 mol) = 3.01 × 10²³ molecules

Answer:

W= -11KJ

Explanation:

Given:

volume expands from 28 L to 51 L

pressure =4.9 atm.

We will need to Convert the pressure to Pascal SI

But 1 atm = 101,325 Pa.

Then,

Pressure= (4.9*101323)/1atm = 5*10^5 pa

Then we need to Convert the volumes to cubic meters

But we know that1 m³ = 1,000 L.

V1= 28L * 1m^3/1000L = 0.028m^3

V2=51L × 1m^3 /1000L =0.051m^3

The work done during the expansion of a gas can be calculated as

W= -P(V2-V1)

W= - 5*10^5(0.051m^3 - 0.028m^3)

W= -1.1× 10^4J

Then we can Convert the work to kiloJoule

But1 kJ = 1,000 J.

W= -1.1× 10^4J× 1kj/1000J

= -11KJ

Answer:

THE SPECIFIC HEAT OF THE METAL IS 0.4843 J/G °C

Explanation:

Heat involved in the reaction is 169.5 J

mass of the metal = 10 g

Change in temperature = 60 °C - 25 °C = 35 °C

Specific heat of the metal = unknown

Specific heat of a metal or substance is the amount of heat per unit mass required to raise the temperature by one degree Celsius.

Using the formula for heat of a reaction, which is:

Heat = mass * specific heat * change in temperature

Heat = m C ΔT

Re-arranging the formula by making C the subject of the formula, we get:

C = Heat / m ΔT

C = 169.5 J / 10 g * 35 C

C = 169.5 J / 350 g °C

C = 0.4843 J/g°C

So therefore, the specific heat of the metal is 0.4843 J/ g°C

Answer:

[tex]\large \boxed{9.780 \times 10^{4}\text{ u}}[/tex]

Explanation:

The molecular mass of a monomer unit is:

C₂H₃Cl = 2×12.01 + 3×1.008 + 35.45 = 24.02 + 3.024 + 35.45 = 62.494 u

For 1565 units,

[tex]\text{Molecular mass} = \text{1565 units} \times \dfrac{\text{62.494 u}}{\text{1 unit }} = \mathbf{9.780 \times 10^{4}}\textbf{ u}\\\\\text{The molecular mass of the chain is $\large \boxed{\mathbf{9.780 \times 10^{4}}\textbf{ u}}$}[/tex]

Answer:

14.32g

Explanation:

Initial temperature = 83.8°C

Final temperature = 77.1°C

Temperature change, ΔT = 83.8°C - 77.1°C = 6.7

Heat, H = 167J

Specific heat, c = 1.740J/g °C

m = ?

All these parameters are related with the equation below;

H = mcΔT

m = H / cΔT

m = 167 /  (1.740 * 6.7)

m = 167 / 11.658 = 14.32g

Answer:

Vitamin C and B complex is the water soluble.but in question option is A abd C so, among them vitamin C is the water soluble vitamin.

Explanation:

Because it is easily soluble in water and when there is more amount of asorbic acid it has to be mixed in urine and are released out from body.

hope it helps..

A) The specific humidity of the air with the given parameters is;

w1 = 0.00967

B) The relative humidity of the air with the given parameters is;

Φ1 = 0.459

C) The enthalpy of the air in KJ/kg dry air with the given parameters is;

h1 = 49.75 KJ/Kg

Correct question is;

The dry- and wet-bulb temperatures of atmospheric air at 95 kPa are 25 and 17 °C, respectively. Determine (a) the specific humidity, (b) the relative humidity, and (c) the enthalpy of the air, in kJ/kg dry air.

We are given;

Atmospheric Pressure;P = 95 KPa

Dry temperature;T1 = 25 °C

Wet temperature;T2 = 17°C

A) From table A-4 attached and at temperature of 17°C and by interpolation, we have a saturation pressure of P_g2 = 1.938 kpa

First of all, we will calculate the specific humidity from the given pressure and saturation pressure with the formula;

w2 = (0.622 × P_g2)/(P - P_g2)

w2 = (0.622 × 1.938)/(95 - 1.938)

w2 = 0.013

Now, let's calculate specific humidity with the enthalpies at 17 °C and by interpolation. We have specific enthalpies from table A-4 as;

h_fg2 = 2460 KJ/Kg

h_g1 = 2546.5 KJ/Kg

h_f2 = 71.36 KJ/Kg

The formula for the specific humidity under these conditions is;

w1 = (c_p(T2 - T1) + w2•h_fg2)/(h_g1 - h_f2)

c_p of air has a value of 1.005 KJ/Kg.°C

Thus;

w1 = (1.005(17 - 25) + 0.013*2460)/(2546.5 - 71.36)

w1 = 0.00967

B) The relative humidity is determined from the equation;

Φ1 = (w1*p)/(0.622 + w1)p_g1

From table A-4 attached and at temperature of 25 °C, we have a saturation pressure of P_g1 = 3.1698 KPa

Φ1 = (0.00967*95)/(0.622 + 0.00967)3.1698

Φ1 = 0.459

C) For the enthalpy of air, h1 we will use the formula;

h1 = (c_p × T1) + (w1 × h_g1)

h1 = (1.005 × 25) + (0.00967 × 2546.5)

h1 = 49.75 KJ/Kg

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Answer:

A) CH3CH2SH

Explanation:

Dispersion forces are weak attractions found between non-polar and polar molecules. The attractions here can be attributed to the fact that a  non-polar molecule sometimes become polar because the constant motion of its electrons may lead to an uneven charge distribution at an instant. If this happens, the molecule has a temporary dipole. This dipole can induce the neighbouring molecules to be distorted and form dipoles as well. The attractions between these dipoles constitute the Dispersion Forces.

Therefore; the greater the molar mass of a compound or molecule, the higher the Dispersion Force. This implies that the compound or molecule with the highest molar mass have the largest dispersion forces.

Now; for option (A)

CH3CH2SH

The molar mass is :

= (12 + (1 × 3 ) +12 + (1 ×2) + 32+1)

= (12 + 3+ 12 + 2 + 32 + 1)

= 62 g/mol

For option (B)

CH3NH2

The molar mass is:

= (12 + (1 ×  3 ) +14 + (1 ×  2)

= (12 + 3 + 14 + 2)

= 31 g/mol

For option (C)

CH4

The molar mass is :

= 12 + (1 × 4)

= 12 + 4

= 16 g/mol

For option (D)

CH3CH3

The molar mass is :

= 12 + ( 1 × 3 ) + 12 + ( 1 × 3)

= 12 + 3 + 12 + 3

= 30 g/mol

Thus ; option (A) has the highest molar mass, as such the largest dispersion force is A) CH3CH2SH

Answer:

THE MOLAR MASS OF THE UNKNOWN COMPOUND IS 242.02 g/mol.

Explanation:

First:

Calculate the change in freezing point:

          Freezing point of pure benzene = 5.5°C

Change in temperature = 5.5 - 3.06 = 2.44 °C

Second:

Using the formula:

Δt = i Kf m

Let's assume i = 1

Kf = 5.12 °C/m

M = x / 0.250 kg of benzene

Then we can calculate x which is the molarity

Re-arranging the formula, we have:

m = Δt / i Kf

x / 0.250 = 2.44 / 1 * 5.12

x = 2.44 * 0.250 / 5.12

x = 0.61 / 5.12

x = 0.119 M

Since it is well known that molarity is the mass of a substance divided by its molar mass. We can then calculate the molar mass.

Molar mass = Mass / molarity

Molar mass = 28.8 g / 0.119 M

Molar mass =242.02 g/mol

Hence, the molar mass of the unknown molecular compound is 242.02 g/mol.

Answer:

Light is composed of particles and travels in a straight line.

Explanation:

The general consensus among scientists in Sir Isaac Newton's time in the early 1700s was that light was composed of a steady stream of particles, since it was observed that light traveled in a straight line and was able to pass through a vacuum. They argued along the lines of Sir Isaac Newton that since sound travels in waves and cannot travel though a vacuum, light must consist of something other than waves, such as particles.

Also, on reflection of light from rough surfaces, the particle theory suggests that if the surface is very rough, the particles bounce away at different angles from the surface, scattering the light as is confirmed by experimental observation.

In his 1704 book Opticks, Sir Isaac Newton stated that "Light is never known to follow crooked passages nor to bend into the shadow". This idea lent support to the particle theory, which proposes that light particles must always travel in straight lines. If the particles encounter the edge of a barrier, then they will cast a shadow because the particles not blocked by the barrier continue on in a straight line and cannot spread out behind the edge. This was observed in eclipses as well as formation of shadow of objects.

Answer:

Light is composed of particles and travels in a straight line.

Explanation:

PF The majority of scientists in the early 1700s agreed that light must be particle-like, since it was apparent that light traveled in a straight line and was able to pass through a vacuum. Their logic was that since sound travels in waves and can't travel though a vacuum, light must consist of something other than waves, such as particles.

Answer:

alcohol

Explanation:

Since in its chemical structure it presents an amide, amine and aromatic ring group.

What this drug does is inhibit the protease of the HIV retrovirus, the protease is an enzyme that catalyzes proteins.

Answer:

B

Explanation:

Heat capacity = mass x specific heat capacity.

(C = mc)

87.2 = 368 x c

= 0.237 J/g.°C

Answer:

1 = 3.75L

2 = 26.91L

3 = 18.37L

Explanation:

Hello,

The question above can be solved when we know Avogadro's law which states that the volume of a fixed mass of gas is directly proportional the number of moles present provided temperature and pressure are kept constant.

Mathematically,

N = kV k = n/v

N1/V1 = N2/V2 = N3/V3 =......=Nn/Vn

N1 = 1.20 moles

V1 = 7.50L

1) if half of the Ne atoms escaped what would be the final volume.

1 mole of Ne = 6.022×10²³ atoms

½(1.20) moles of Ne = ?

0.6 moles of Ne = ?

1 mole = 6.022×10²³ atom

1.2 moles = ?

x = 1.2 × 6.022×10²³ atoms

x = 7.23×10²³atoms

If ½ of 7.23×10²³ atoms escaped, how many would be left

½ × 7.23×10²³ atoms = 3.61×10²³atoms

Now we have to find the number of moles and then use our equation.

1 mole = 6.022×10²³ atoms

y mole = 3.61×10²³ atom

y = 0.6 mole

N2 = 0.6 mole

N1 / V1 = N2 / V2

Make V2 the subject of formula,

V2 = (N2 × V1) / N1

V2 = (0.6 × 7.50) / 1.20

V2 = 3.75L

The volume after half of the Ne atoms escaped is 3.75L

2)

When a sample of 3.10 mole is added to 1.20 moles present

N1 = 1.20

V1 = 7.51

N2 = (1.20 + 3.10) = 4.30L

V2 = ?

N1 / V1 = N2 / V2

V2 = (N2 × V1) / N1

V2 = (4.30 × 7.51) / 1.20

V2 = 26.91L

The volume of Ne gas if 3.10 moles is added to it is 26.91L

3)

A sample of 35g is added to the 1.20 mole Ne in the container.

We need to convert the mass (35g) to moles. This can be done using mass-molarmass relationships

Number of moles = mass / molar mass

Molar mass of Ne = 20.17g/mol

Number of moles = 35 / 20.17

Number of moles = 1.735 moles

N2 = 1.20 moles + 1.735 moles

N2 = 2.935 moles

N1 / V1 = N2 / V2

V2 = (N2 × V1) / N1

V2 = (2.935 × 7.51) / 1.20

V2 = 18.37L

On addition of 35g of Ne gas to the container, the volume is increased to 18.37L

Answer:

Option E. 2.04 L

Explanation:

Data obtained from the question include:

Molarity of NaCl = 2.25 M

Mole of NaCl = 4.58 moles

Volume =..?

Molarity is simply defined as the mole of solute per unit litre of the solution. It is represented mathematically as:

Molarity = mole /Volume

With the above formula, we can obtain the volume of the solution as follow:

Molarity = mole /Volume

2.25 = 4.58/volume

Cross multiply

2.25 x volume = 4.58

Divide both side by 2.25

Volume = 4.58/2.25

Volume = 2.04 L

Therefore, the volume of the solution is 2.04 L

Answer:

Atomic radius of Strontium is 27.38pm

Explanation:

In a face-centered cubic structure, the edge, a, could be obtained using pythagoras theorem knowing the hypotenuse of the unit cell, b, is equal to 4r:

a² + a² = b² = (4r)²

2a² = 16r²

a = √8 r

As edge length of Strontium is 77.43pm:

77.43pm / √8 = r

27.38pm = r

Answer:

The correct answer is 17.845 hours.

Explanation:

To solve the question, that is, to determine the hours required there is a need to combine the Faraday's law of electrolysis with the Ideal gas law.  

Based on Faraday's law, m = Mit/nF

Here m is the mass in grams, M is the molecular mass, i is the current in amperes, t is time, n is the number of moles of electron per mole of oxygen formed and F is the Faraday's constant (the value of F is 96487 coulombs/mole).  

From the above mentioned equation,  

t = mnF/Mi ------(i)

Now based on ideal gas law's, PV = nRT or PV = m/M RT, here n = mass/molecular mass.  

So, from the above gas law's equation, m = PVM/RT

Now putting the values of m in the equation (i) we get,  

t = PVMnF/MiRT = PVnF/iRT

Based on the given information, the value of P is 750 torr or 750/760 atm = 0.98 atm, the value of v is 15.0 L, T is 30 degree C or 273 + 30 K = 303 K, i is 3.55 Amperes, and the value of R is 0.0821 atm L/mol K.  

1 mole of oxygen gives 2 moles of electrons, therefore, 2 moles of oxygen will give 4 moles of electrons.  

Now putting the values we get,  

t = PVnF/iRT

= 0.98 atm × 15.0 L × 4 moles of electron × 96487 coulombs per mole / 3.55 coulomb per sec × 0.0821 atm L per mole-K × 303 K

= 64243.81 secs or 64243.81/3600 hr  

= 17.845 hours

Answer:

211.4g/mol.

Explanation:

Data obtained from the question includes:

Mass of unknown compound = 0.98g

Mass of solvent = 10.30g

Molality = 0.45 M

Next, we shall determine the number of mole of the unknown compound present in the solution.

This can be obtained as follow:

Molality = mole /kg of solvent

Mole of the unknown compound =.?

Mass of solvent = 10.30g = 10.30/1000 = 0.0103Kg

Molality = 0.45 M

Molality = mole /kg of solvent

0.45 = mole /0.0103

Cross multiply

Mole = 0.45 x 0.0103

Mole = 4.635×10¯³ mole

Therefore the mole of the unknown compound that dissolve in solution is 4.635×10¯³ mole

Now, we can obtain the molar mass of the unknown compound as follow:

Mole of the unknown compound = 4.635×10¯³ mole

Mass of unknown compound = 0.98g

Molar mass of the unknown compound =?

Mole = mass /Molar mass

4.635×10¯³ = 0.98 /Molar mass

Cross multiply

4.635×10¯³ x molar mass = 0.98

Divide both side by 4.635×10¯³

Molar mass = 0.98 / 4.635×10¯³

Molar mass = 211.4g/mol.

Therefore, the molar mass of the unknown compound is 211.4g/mol.

The molecular mass of the unknown has been 211.66 g/mol.

Molality can be defined as the moles of the solute per kg of solvent.

Molality can be expressed as:

Molality = [tex]\rm \dfrac{Mass\;of\;solute\;(g)}{molecular\;mass\;of\;solute}\;\times\;\dfrac{1000}{Mass\;of\;solvent\;(g)}[/tex] ......(i)

The given unknown has been the solute.

The mass of solute = 0.98 g.

The mass of solvent = 10.30 g.

The molality of the solution formed has been = 0.45 m.

Substituting the values in equation (i):

0.45 m = [tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}\;\times\;\dfrac{1000}{10.30\;g}[/tex]

0.45 m = [tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}\;\times\;97.087[/tex]

[tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}[/tex]  =  [tex]\rm \dfrac{0.45}{97.087}[/tex]

[tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}[/tex]  = 0.00463

Molecular mass of solute = [tex]\rm \dfrac{0.98}{0.00463}[/tex]

Molecular mass of solute = 211.66 g/mol.

The molecular mass of the unknown has been 211.66 g/mol.

For more information about the molality of the solution, refer to the link:

https://brainly.com/question/8103026