7. Aspirin has a pKa of 3.4. What is the ratio of A to HA in: (a) the blood (pH 7.4) (b) the stomach (pH 1.4) =

Answer:

Each cyclist will need to drink 619 l

Explanation:

Hi there!!

First, let´s convert the miles to kilometers:

If 1.0 mi = 1609 m, then 385 mi will be:

385 mi · (1609 m/ 1.0 mi) ·  (1 km/ 1000 m) = 619 km

Now, if each cyclist need to drink one liter water per kilometer ( I think that´s a lot of water!), for the entire journey each cyclist will need to drink:

619 km · 1 l/km = 619 l

Then, each cyclist will need to drink 619 l.

Answer:

The required volume is 1.6 x 10³mL.

Explanation:

When we want to prepare a dilute solution from a concentrated one, we can use the dilution rule to find out the required volume to dilute. This rule states:

C₁ . V₁ = C₂ . V₂

where,

C₁ and V₁ are the concentration and volume of the concentrated solution

C₂ and V₂ are the concentration and volume of the dilute solution

In this case, we want to find out V₁:

C₁ . V₁ = C₂ . V₂

[tex]V_{1} = \frac{C_{2}.V_{2}}{C_{1}} = \frac{1.5M \times1.11.10^{4}mL }{10.2M} =1.6\times10^{3} mL[/tex]

Answer:

The list and discussions are stated below:

Explanation:

Good Laboratory Practice (GLP) is extremely important.

1. Organization

With GLP we can guarantee an organized work environment, which is essencial in a laboratory.

2. Safety

GLP promotes laboratory safety for personell, avoiding unecessary risks and preventing accidents.

3. Quality control

GLP ensures that experiments made and products developed in a laboratory have the demanded quality.

4. Reliability of results

GLP promotes quality of results reporting, wich directly influences the reliability of results.

Answer:

A

Explanation:

The mass of a compound is the sum of the masses of its component (a total is equal to the sum of its parts).

Answer:

d. 1600 calories

Explanation:

The heat of fusion of water, L, is the amount of heat per gram required to melt the ice to water, a process which takes place at a constant temperature of 0 °C. The specific heat of water, c, is the amount of heat required to change the temperature of 1 gram of water by 1 degree Celsius.

We will convert the units of c from Jg⁻¹°C⁻¹ to cal·g⁻¹°C⁻¹ since the answers are provided in calories. The conversion factor is 4.18 J/cal.

(4.18 Jg⁻¹°C⁻¹)(cal/4.18J) = 1 cal·g⁻¹°C⁻¹

First we calculate the heat required to melt the ice, where M is the mass:

Q = ML = (15 g)(80 cal/g) = 1200 cal

Then, we calculate the heat required to raise the temperature of water from 0 °C to 25 °C.

Q = mcΔt = (15 g)(1 cal·g⁻¹°C⁻¹)(25 °C - 0 °C) = 380 cal

The answer is rounded so that there are two significant figures

The total heat required for this process is (1200 cal + 380 cal) = 1580 cal

The rounded answer is 1600 calories.

Answer:

There are three major sources of errors in numerical method, namely human error, truncation error and round off error, but here we have to discuss only two sources-

Answer:

sdfsdfsdf

Explanation:dsf

Answer:

Na⁺ tends to interact with the hardest base, which is water. Ag⁺ tends to interact with the softest (hardless) base, which is Cl⁻.

Explanation:

The HSAB concept says that hard acids are small ions with low electronegativity, while hard bases are electron donating groups with high electronegativity and low polarizability. The HSAB concept also says that hard acids will tend to react with hard bases. The opposite is valid for soft acids and soft bases.

Na⁺ is a hard acid

Ag ⁺ is a soft acid

Cl⁻ is a hard base

H₂O is a harder base than Cl⁻

Therefore, when in water, the Na⁺ tends to react with water, because it is a harder base than Cl⁻. However, as Ag⁺ is a soft acid, it will tend to stay with the less hard base, which is Cl⁻.

Answer: Option (a) is the correct answer.

Explanation:

Alkynes are the hydrocarbons, that is, they contain only atoms of carbon and hydrogen. Their general chemical formula is [tex]C_{n}H_{2n-2}[/tex], where n is a whole number.

A compound that contains a double or triple bond is known as an unsaturated compound. An alkyne contains a triple bond and it is also an unsaturated compound.

Thus, we can conclude that alkynes are hydrocarbons that have at least one triple bond between carbon atoms.

The coffee solution is unsaturated with sugar.

A sugar and water solution is created when sugar dissolves in water. In this case, Vanessa pours 52 kilograms of table sugar, which is the solute, into 100 mL of coffee, which is the solvent. Since most of the sugar does not dissolve, the coffee solution can be considered unsaturated with sugar.

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Answer:

Q = 47.1 kW

Texit = 25.93ºC

Explanation:

The heat transfer is occurring by convection, which means that the heat is flowing from different materials (tube for water). So, by Newton Cooling Law:

Q = h x A x ΔT

The area of the tube will be :

A = πdL

Where d is the diameter and L is the length.

d = 2.5 cm = 0.025 m

A = 3.14x0.025x4 = 0.314 m²

Then

Q = 3000x0.314x50

Q = 47100 W = 47.1 kW

By the heat equation for water, knowing that the specific heat (c) of water is 4.5 kJ/ºC

Q = mcΔT

47.11 = 0.5x4.5x(Texits - Tenters)

47.1 = 2.25x(Texits - 5ºC)

Texits - 5ºC = 20.93 ºC

Texits = 25.93ºC

47.1 kW is the rate of heat transfer and 25.93ºC is the temperature of the water at exit.

We can calculate the rate of heat transfer of the water by using the Newton's cooling law as:

Q = h x A x ΔT, where

h = heat transfer coefficient = 3000 W/m².°C (given)

A = surface area of heat transfer

ΔT = change in temperature = 50°C (given)

First we calculate the area by using the below formula:

A = πdL, where

d = diameter of tube = 2.5cm = 0.025m

L = length of tube = 4m

A = 3.14 x 0.025 x 4 = 0.314 m²

Therefore, rate of heat transfer is:

Q = 3000 x 0.314 x 50 = 47100 W = 47.1 kW

Now we calculate the rise in temperature by using the below formula:

Q = mcΔT

47.11 = 0.5 x 4.5 x (Texits - Tenters)

47.1 = 2.25 x (Texits - 5ºC)

Texits - 5ºC = 20.93 ºC

Texits = 25.93ºC

Hence, 47.1 kW is the rate of heat transfer and 25.93ºC is the temperature of exit water.

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Answer:

unsaturated solution

Explanation:

This solution is made by the coffee, which is the solvent and the sugar, which is the solute. The solute dissolves in the solvent.

Sugar starts to precipitate because it cannot dissolve anymore. This means that the solution at the equilibrium point and is saturated. Since more coffee or solvent is added, the solution will now be able to dissolve more sugar. This means that the solution is unsaturated

Answer:

t = 71.47 min

Explanation:

Using integrated rate law for first order kinetics as:

[tex][A_t]=[A_0]e^{-kt}[/tex]

Where,  

[tex][A_t][/tex] is the concentration at time t

[tex][A_0][/tex] is the initial concentration

Given:

20.8 % is decomposed which means that 0.208 of [tex][A_0][/tex] is decomposed. So,

[tex]\frac {[A_t]}{[A_0]}[/tex] = 1 - 0.208 = 0.792

t = 7.8 min

[tex]\frac {[A_t]}{[A_0]}=e^{-k\times t}[/tex]

[tex]0.792=e^{-k\times 7.8}[/tex]

k = 0.0299 min⁻¹

Also,

Given:

88.2 % is decomposed which means that 0.882 of [tex][A_0][/tex] is decomposed. So,

[tex]\frac {[A_t]}{[A_0]}[/tex] = 1 - 0.882 = 0.118

t = ?

[tex]\frac {[A_t]}{[A_0]}=e^{-k\times t}[/tex]

[tex]0.118=e^{-0.0299\times t}[/tex]

t = 71.47 min

Answer:

The percentage mass of Manganese is 34.76%

Explanation:

The formula of potassium permanganate is KMnO4

Its molar mass is 158.034 g/mol.

The molar mass of Mn is 54.938 g/mol.

Percentage mass of Mn is:

[tex]Mn=\frac{54.938}{158.034}100[/tex]

Mn=34.76%

Answer: The number of hydrogen molecules in the given amount is [tex]1.454\times 10^{25}[/tex]

Explanation:

To calculate the number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

Given mass of hydrogen gas = 48.3 g

Molar mass of hydrogen gas = 2 g/mol

Putting values in above equation, we get:

[tex]\text{Moles of hydrogen gas}=\frac{48.3g}{2g/mol}=24.15mol[/tex]

According to mole concept:

1 mole of a compound contains [tex]6.022\time 10^{23}[/tex] number of molecules

So, 24.15 moles of hydrogen gas will contain = [tex]24.15\times 6.022\times 10^{23}=1.454\times 10^{25}[/tex] number of molecules.

Hence, the number of hydrogen molecules in the given amount is [tex]1.454\times 10^{25}[/tex]

The correct chemical formula for Iron(III) hydroxide is Fe(OH)3, which is formed by combining one iron ion with a +3 charge (Fe3+) with three hydroxide ions (OH-).

The chemical formula for Iron(III) hydroxide is Fe(OH)3. This compound consists of an iron ion with a +3 charge (Fe3+) and three hydroxide ions (OH-). The number in parentheses after iron indicates the oxidation state of iron, which in this case is +3. The formula reflects the stoichiometry required to balance the charges, resulting in one Fe3+ for every three OH- ions to form the neutral compound. Therefore, the correct answer is Fe(OH)3.

The correct answer is d. Fe(OH)₃.

Answer:

The correct answer is letter c: The exit temperature of hot fluid is always more than the exit temperature of cold fluid

Explanation:

Heat exchangers are used to exchange heat between two fluids so they are helpfull in cooling and heating processes. After the exchange the temperatures of the fluids that participate are changed so both option d and b: (The exit temperature of hot fluid is always equal to the exit temperature of cold fluid) and (We cannot predict comparison between exit temperatures of hot fluid and cold fluid) are INCORRECT.

In which has to be with option a: (The exit temperature of hot fluid is always less than the exit temperature of cold fluid). It is INCORRECT because the maximum temperature that can be reached by the cold fluid is the one that has the hot fluid. That is the ideal situation of thermal equilibrium in which both fluids leave the exchanger at the same temperature, that does no happen, so the real situation is the one described in option c "The exit temperature of hot fluid is always more than the exit temperature of cold fluid". Both fluids exchange heat till the force that may that possible allows that, that force is the difference of temperature between them so when that difference reachs a minimum the process stops.

Final answer:

In parallel flow heat exchangers, the exit temperature of the hot fluid is always less than the exit temperature of the cold fluid, as heat transfer occurs from the hot to the cold fluid according to the second law of thermodynamics.

Explanation:

The correct answer to the question is The exit temperature of hot fluid is always less than the exit temperature of cold fluid. In parallel-flow heat exchangers, both the hot and cold fluids enter the exchanger at different ends and flow in the same direction. As heat is transferred, the temperature of the hot fluid decreases while the temperature of the cold fluid increases. Due to the second law of thermodynamics, heat transfer flows spontaneously from a hotter object to a cooler object but never in reverse. Therefore, the heat will always flow from the hot fluid to the cold fluid until they reaches equilibrium or until the hot fluid exits at a lower temperature than it entered.

Moreover, the efficiency of heat engines, which are related to heat exchangers, is higher when there is a large temperature difference between the hot and cold reservoirs, as stated in the provided information. This implies that in most practical situations, especially when the hot and cold fluids are allowed to reach equilibrium, the exit temperature of the hot fluid will be less than that of the cold fluid (option a). However, if the length or design of the heat exchanger does not allow them to reach equilibrium, the exit temperatures may vary but the hot fluid is expected to cool down during the process.

Explanation:

(a)  An isochoric process is defined as the process in which volume of a system remains constant.

For example, an air conditioner follows an isochoric process.

(b) As pressure and temperature can change in an isochoric process but volume will remain the same.

Hence, heat can also be exchanged in an isochoric process. Whereas in an adiabatic process heat remains 0. Therefore, it means the in adiabatic process there occurs no exchange of heat between the system and its surrounding.

(c) It is given that V = 100 L = 0.1 [tex]m^{3}[/tex]   (as 1 L = 0.001 [tex]m^{3}[/tex])

               [tex]P_{1}[/tex] = [tex]10 \times 10^{6} Pa[/tex]

               [tex]P_{2}[/tex] = [tex]15 \times 10^{6} Pa[/tex]

Relation between work, pressure and volume is as follows.

                     W = [tex]\Delta PV[/tex]

                         = PdV + VdP

                          = 0 + 0.1 [tex]m^{3} (15 - 10) \times 10^{6}[/tex]

(Since V = constant so, dV = 0)

                          = [tex]5 \times 10^{5} J[/tex]

Thus, we can conclude that work done is [tex]5 \times 10^{5} J[/tex].

Answer:

pH = 11

Explanation:

The concentration of OH⁻ in pure water is 10⁻⁷ M. If a substance increases OH⁻ concentration by 10⁴, the new concentration will be:

[OH⁻] = 10⁴ x 10⁻⁷ M = 10⁻³M

We can calculate pOH using it's definition:

pOH = -log[OH⁻] = -log (10⁻³) = 3

Then, we can find out pH using the following relation:

pH + pOH = 14

pH = 14 - pOH = 14 -3 = 11

Since pH = 11 is higher than 7, we can confirm that the substance is a base.

A theory is a well-substantiated explanation of observed phenomena that has undergone rigorous testing and validation through the scientific method.

A consistent explanation of known observations is called a theory. In the realm of science, a theory is more than just a simple guess; it is a well-substantiated explanation that is grounded in a significant body of evidence. This evidence consists of a series of facts and observations that, when considered collectively, give a reliable account of a part of the natural world. To arrive at a theory, the scientific method is typically employed, involving systematic observations, forming hypotheses, conducting experiments, and refining those hypotheses based on experimental results. When a hypothesis withstands rigorous testing and is capable of explaining a large and diverse range of phenomena, it can evolve into a theory. Scientific theories are valued because they offer comprehensive explanations that are testable and can be modified in the face of new evidence.

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Answer:

[tex]T_{2}=16,97^{\circ}C[/tex]

Explanation:

The specific heats of water and steel are  

[tex]Cp_{w}=4.186 \frac{KJ}{Kg^{\circ}C}[/tex]

[tex]Cp_{s}=0.49 \frac{KJ}{Kg^{\circ}C}[/tex]

Assuming that the water and steel are into an adiabatic calorimeter (there's no heat transferred to the enviroment), the temperature of both is identical when the system gets to the equilibrium [tex]T_{2}_{w}= T_{2}_{s}[/tex]  

An energy balance can be written as

[tex] m_{w}\times Cp_{w}\times (T_{2}- T_{1})_{w}= -m_{s}\times Cp_{s}\times (T_{2}- T_{1})_{s} [/tex]  

Replacing

[tex] 1.28Kg\times 4.186\frac{KJ}{Kg^{\circ}C}\times (T_{2}-10^{\circ}C)= -0.385Kg\times 0.49 \frac{KJ}{Kg^{\circ}C} \times (T_{2}-215^{\circ}C)[/tex]

Then, the temperature [tex]T_{2}=16,97^{\circ}C[/tex]

The equilibrium temperature given that You drop a piece of steel at 215 °C into the water at 10.0 °C in the calorimeter is 16 °C

The equilibrium temperature given that You drop a piece of steel at 215 °C into the water at 10.0 °C can be calculated as follow:

[tex]MC(T - T_e) = M_wC_w(T_e - T_w)\\\\0.385\ \times\ 420(215 - T_e) = 1.28\ \times\ 4184(T_e - 10)[/tex]

[tex]34765.5 - 161.7T_e = 5355.52T_e - 53555.2\\\\34765.5\ +\ 53555.2 = 5355.52T_e\ +\ 161.7T_e\\\\88320.7 = 5517.22T_e\\\\T_e = \frac{88320.7}{5517.22} \\\\T_e = 16\ \textdegree C[/tex]

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As the volume of confined gas decreases at the constant temperature, the pressure exerted by the gas increases .  The correct option is C.

Boyle–Mariotte law is a gas law, shows the relation between pressure and volume. With the increase in the volume, the pressure decreases.

The pressure exerted by the mass, is inversely proportional to the volume of the gas.

Thus, the correct option is C, increases.

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Answer:

For 1: The correct answer is Ge.

For 2: The correct answer is Te.

For 3: The correct answer is Ba.

For 4: The correct answer is Ag.

Explanation:

Ionization energy is defined as the energy required to remove an electron from the outermost shell of an isolated gaseous atom. It is represented as [tex]E_i[/tex]

[tex]X(g)\rightarrow X^+(g)+1e^-;E_i[/tex]

Ionization energy increases as we move from left to right in a period. This happens because the atomic radius of an element decreases moving across a period, which increases the effective attraction between the negatively charged electrons and positively-charged nucleus. Hence, the removal of electron from the outermost shell becomes difficult and requires more energy.

Ionization energy decreases on moving from top to bottom in a group. This happens because the number of shells increases as we move down the group. The electrons get added in the new shell. So, the shielding of outermost electrons from the inner ones is more which decreases the attraction between the electrons and the nucleus. Hence, the removal of electron from the outermost shell becomes easy and requires less energy.

For the given options:

Chlorine is the 17th element of the periodic table belonging to Period 3 and Group 17.

Germanium is the 32nd element of the periodic table belonging to Period 4 and Group 14.

Hence, germanium will have smaller first ionization energy.

Tellurium is the 52nd element of the periodic table belonging to Period 5 and Group 16.

Selenium is the 34th element of the periodic table belonging to Period 4 and Group 16.

Hence, tellurium will have smaller first ionization energy.

Barium is the 56th element of the periodic table belonging to Period 6 and Group 2.

Titanium is the 22nd element of the periodic table belonging to Period 4 and Group 4.

Hence, barium will have smaller first ionization energy.

Copper is the 29th element of the periodic table belonging to Period 4 and Group 11.

Silver is the 47th element of the periodic table belonging to Period 5 and Group 11.

Hence, silver will have smaller first ionization energy.

Ionization energy increases across the period but decreases down the group.

First ionization energy of an element refers to the energy required to remove an electron from the atom. Ionization energy is a periodic trend that increases across the period but decreases down the group.

The following are true regarding the statements in the question;

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Answer:

Freezing temperature:

         It is the temperature at which a liquid state of substance converts in to the solid state.

Ex :The freezing temperature of water is 0°C.

Melting temperature:

          It is the temperature at which a solid state of any substance covert in to the liquid sates.

Ex : Temperature above the 0°C of water

The heat required to melt the solid is know as heat of fusion. Heat of fusion of water nearly about 334 J.

The heat required to covert liquid state to vapor state is known as heat of vaporization.The heat of vaporization of water nearly 2230 J.

Answer: The weight fraction of ethanol in the mixture is

Explanation:

We are given:

Mass of water = 1 kg = 2.205 lb   (Conversion factor:  1 kg = 2.205 lb)

Mass of ethanol = 1.9 lb

Mass of ethyl acetate = 4.6 lb

Mass of mixture = [2.205 + 1.9 + 4.6] = 8.705 lb

To calculate the percentage composition of ethanol in mixture, we use the equation:

[tex]\%\text{ composition of ethanol}=\frac{\text{Mass of ethanol}}{\text{Mass of mixture}}\times 100[/tex]

Mass of mixture = 8.705 lb

Mass of ethanol = 1.9 lb

Putting values in above equation, we get:

[tex]\%\text{ composition of ethanol}=\frac{1.9lb}{8.705lb}\times 100=21.8\%[/tex]

Hence, the weight fraction of ethanol in the mixture is 21.8 %

Answer:

49.3% 81Br and 50.7% 79Br or [tex]\frac{493}{1000}[/tex] 81Br and [tex]\frac{507}{1000}[/tex] 79BR

Step-by-step explanation:

To get the fraction-of-occurrences of the isotopes we must write the following equation. x is the isotopic abundance of 81Br, we can use 1 - x to get the isotopic abundance of 79Br.

(78.918)(1 - x) + (80.916)(x) = 79.903

78.918 - 78.918x + 80.916x = 79.903

1.998x = 0.985

x = 0.493

0.493 × 100 = 49.3% 81Br

100 - 49.3 = 50.7% 79Br

49.3% 81Br and 50.7% 79Br or [tex]\frac{493}{1000}[/tex] 81Br and [tex]\frac{507}{1000}[/tex] 79BR

Answer: liquid water

Explanation:

Entropy is the measure of randomness or disorder of a system. If a system moves from an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.

[tex]\Delta S[/tex] is positive when randomness increases and [tex]\Delta S[/tex] is negative when randomness decreases.

Gases have more entropy than liquids and liquids have more entropy than solids due to movement of particles.

Thus liquid water will have more entropy than crushed ice.

The correct answer is liquid water. Liquid water has a higher entropy than crushed ice because the transition from solid to liquid increases the disorder and number of possible microstates for water molecules.

The question of which substance, liquid water or crushed ice, has the highest entropy touches upon the concept of phase transitions and the disorder of molecular systems. The entropy of a system is a measure of its randomness or disorder, where a greater number of possible microstates corresponds to higher entropy.

When ice melts into water, the structure of water molecules becomes less ordered, allowing more freedom of movement. This transition from a solid to a liquid state results in an increase in entropy. Therefore, liquid water has a higher entropy than crushed ice because the molecules in the liquid state have more freedom to move and occupy a greater number of microstates.

Answer:

[tex]3.4\times 10^3 eggs[/tex] are produces are in a month.

Explanation:

Quantity of eggs produced by the chicken in a month = 284 dozens

1 dozen = 12 eggs

Number of eggs in a month:

[tex]284 dozens = 284\times 12 eggs =3,408 eggs\approx 3.4\times 10^3 eegs[/tex]

[tex]3.4\times 10^3 eggs[/tex] are produces are in a month.

Answer:

The answer is b)

Explanation:

In packed column the mass transfer area is higher and the packing can be random, that could provoque an increase in the pressure, because obstruction of the mass flux, While in a tray column the sieves can have specific porosity and the flux of mass can be facilitated, thus the pressure drop.  

Answer:

Few important points related to [tex]S_N2[/tex] reaction:

1. [tex]S_N2[/tex] is a one-step reaction that follows second order kinetics.

2. In [tex]S_N2[/tex] reaction, a transition state is formed in situ.

3. Strong nucleophiles like [tex]OH^- \ or\  CN^-[/tex] are used in case of bi-molecular nucleophilic substitution reaction.

Ethyl acetate can be prepared by a second-order nucleophilic substitution reaction between acetic acid and ethyl bromide.  

The reaction between acetic acid and ethyl bromide is drawn below:

In the SN2 reaction to create ethyl acetate, the nucleophile acetate ion attacks the alkyl bromide, leading to the formation of ethyl acetate and bromide ions.

Ethyl acetate can be prepared by an SN2 reaction. In this context, an alkylbromide and nucleophile initiate the reaction. Ethyl bromide (CH3CH2Br) would be the alkylbromide used in the reaction. The nucleophile, in this case, would be acetate ion (CH3COO-).

Ethyl bromide is a good leaving group and acetate ion is a strong nucleophile, which comes from acetic acid (ethanoic acid). In SN2 reactions, the nucleophile attacks the substrate, and the leaving group (Br- in this case) leaves, leading to a reverse configuration. In this reaction, the nucleophile (acetate ion) will attack the alkyl bromide, resulting in the formation of ethyl acetate, CH3COOCH2CH3, and bromide ions, which is a good leaving group.

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Answer:

13701.66 g

Explanation:

Moles is denoted by given mass divided by the molecular mass ,  

Hence ,  

n = w / m

n = moles ,  

w = given mass ,  

m = molecular mass .

From the question ,

114.0 g-moles of cumene means ,

Moles of cumene = 114.0 g-mol

The  Chemical formula of cumene = C₉H₁₂

As we know the molecular mass of cumene = 120.19 g /mol

using the above formula ,

n = w / m

w = n * m

Putting the corresponding values -

w = (114.0 g-mol) * 120.19 g /mol

w = 13701.66 g