Assuming constant pressure, rank these reactions from most energy released by the system to most energy absorbed by the system, based on the following descriptions: 1. Surroundings get colder and the system decreases in volume. 2. Surroundings get hotter and the system expands in volume. 3. Surroundings get hotter and the system decreases in volume. 4. Surroundings get hotter and the system does not change in volume. 5. Also assume that the magnitude of the volume and temperature changes are similar among the reactions. 6. Rank from most energy released to most energy absorbed. To rank items as equivalent, overlap them. A mole of X reacts at a constant pressure of 43.0 atm via the reaction X(g)+4Y(g)→2Z(g), ΔH∘=−75.0 kJBefore the reaction, the volume of the gaseous mixture was 5.00 L. After the reaction, the volume was 2.00 L. Calculate the value of the total energy change, ΔE, in kilojoules.

Answers

Answer 1

Answer: The order from the Most energy released to most Energy   Absorbed Is given as  2---> 4--->,3-->---> 1 

B)-61.9 kJ

Explanation:

The change in the internal energy of a system  is positive if the reaction absorbs energy and  negative if the reaction releases energy. For a system to cause an increase in volume, it must have very high energy built up to be released.

1. Surroundings get colder and the system decreases in volume. Here, the surrounding absorbs energy  resulting in positive  ΔE

2. Surroundings get hotter and the system expands in volume.  Here energy is released causing the system to be negative

3. Surroundings get hotter and the system decreases in volume. Although there is a decreased volume, the system is negative because it releases energy

4. Surroundings get hotter and the system does not change in volume.  System is negative because it releases energy even thgoygh there is no change in volume

Therefore the order from the Most energy released to most Energy   Absorbed Is given as  2---> 4--->,3-->---> 1

b) Using  

 ΔE = q+ w     from 1st law of thermodynamics

 ΔE=  ΔH - P  ΔV

gIven  

 ΔH = -75.0KJ

volume=  A change  from 5.0L TO 2.0L = Final volume - initial volume = 2-5= -3.00L

P= 43.0atm

ΔE=  ΔH - P  ΔV

P  ΔV  = 43 atm x -3 = -129L.atm

We first convert  L-atm to Joules.

1 L-atm = 101.325 Joules.  

129L.atm = 129 x 101.325 = - 13071 J

to KJ becomes

13071/1000 = - 13.071KJ

Recall ΔE=  ΔH - P  ΔV and putting values

ΔE  = -75.0 - (-13.071 KJ)= -75.0 kJ + 13.071 kJ = -61.9 kJ


Related Questions

can a kind human being help me with this table at least only with the first burning fire wood someone please ​

Answers

Answer:

See below

Explanation:

* Burning fire wood is given to be our first option. Now burning tends to be a property of wood, and it does effect the chemical compositions of it. Wood, in the presence of fire / oxygen, turns into ash and carbon dioxide.

* Decomposition is recognized as a chemical change, and heating copper carbonate is a perfect example of decomposition. When energy is added to this chemical process, the copper carbonate decomposes into copper oxide.

* Mixing sodium chloride solution and silver nitrate solution. When this reaction takes place, a white precipitate of AgCl is formed. And of course, this is a chemical reaction.

* When acids or bases come in contact with citric acid, the pH degree changes much. Due to this, carbon dioxide bubbles are formed.

* When eggs are fried they absorb the heat in the pan. Doing so the egg starts to curl a bit, resulting in the formation of new particles.

_______________________________________________________

I hope this gave you a start!

408 J of energy is transferred to a system consisting of 2.0 moles of an ideal gas. If the volume of this gas stays at a constant 4.4 L, calculate the change in internal energy of the gas.

Answers

Answer: The change in internal energy of the gas is +408 J

Explanation:

According to first law of thermodynamics:

[tex]\Delta E=q+w[/tex]

[tex]\Delta E[/tex] =Change in internal energy

q = heat absorbed or released

w = work done or by the system

w = work done on the system= [tex]-P\Delta V[/tex]

As volume is constant , [tex]\Delta V[/tex] = 0 and w = 0.

q = +408J   {Heat absorbed by the system is positive}

[tex]\Delta E=+408J+(0J)=+408J[/tex]

Thus the change in internal energy of the gas is +408 J

16. Which of the following is considered to be a vector?
A. Velocity
B. Temperature
C. Time
D. Mass

Answers

Answer:

Velocity

Explanation:

it is the rate of displacement over time in a SPECIFIED DIRECTION i.e it has both magnitude and direction

Which of the following is evidence of a physical change?

A) burning
B) melting
C) decomposing
D) rusting

Answers

The answer is >>>>
C) decomposing
A RESPOSTA CORRETA É A c

What type of chemical reaction occurs between AgNO3 (sliver nitrate) and Cu (Copper)?

Answers

Answer:

The answer is option c.

I hope this helps you.

Choose the correct option for the redox reaction below : 8H+(aq) + MnO4-(aq) + 5Fe2+(aq) → Mn2+(aq) + 5Fe3+(aq) 4H2O(l) H+ (oxidized or reduced) Answer 1 Choose... MnO4- (oxidizing or reducing agent) Answer 2 Choose... Fe2+ (oxidizing or reducing agent) Answer 3 Choose... Fe2+ (oxidized or reduced) Answer 4 Choose... O in MnO4- (oxidized or reduced) Answer 5 Choose... Mn in MnO4- (oxidized or reduced) Answer 6 Choose...

Answers

Explanation:

8H+(aq) + MnO4-(aq) + 5Fe2+(aq) → Mn2+(aq) + 5Fe3+(aq) + 4H2O(l)

To determine if a substance was reduced or oxidized, the oxidation number at the reactant and product side is compared.

When oxidation occurs, an element loses electrons and its oxidation number increases (becomes more positive). When reduction occurs, an element gains electrons and its oxidation number decreases or is reduced (becomes more negative).

H+ (oxidized or reduced) Answer 1 Choose...

There is an increase in oxidation number from 0 to 1. This means H+ was oxidized.

MnO4- (oxidizing or reducing agent) Answer 2 Choose...

In chemistry, an oxidizing agent is a substance that has the ability to oxidize other substances — in other words to accept their electrons

MnO4- is a strong oxidizing agent.

Fe2+ (oxidizing or reducing agent) Answer 3 Choose...

A reducing agent means it will itself get oxidized. In  this reaction, Fe2+ is the reducing agent.

Fe2+ (oxidized or reduced) Answer 4 Choose...

Oxidized

O in MnO4- (oxidized or reduced) Answer 5 Choose...

There is no change in oxidation number of , so it was neither reduced nor was it oxidized.

Mn in MnO4- (oxidized or reduced) Answer 6 Choose...

There is a decreaase in oxidation number from +7 to +2. This means reduction.

Combustion analysis of a 13.42-g sample of estriol (which contains only carbon, hydrogen, and oxygen) produced 36.86 g CO2 and 10.06 g H2O. The molar mass of estriol is 288.38 g/mol . Find the molecular formula for estriol. Express your answer as a chemical formula.

Answers

Answer:

C18H24O3

Explanation:

Step 1:

Data obtained from the question. This include the following:

Mass of estriol = 13.42g

Mass of CO2 = 36.86g

Mass of H2O = 10.06g

Molar mass of estriol = 288.38g/mol

Step 2:

Determination of the mass of Carbon (C), Hydrogen (H) and Oxygen (O) present in the compound. This is illustrated below:

For Carbon, C:

Molar mass of CO2 = 12 + (2x16) = 44g/mol

Mass of C in CO2 = 12/44 x 36.86 = 10.05g

For Hydrogen, H:

Molar Mass of H2O = (2x1) + 16 = 18g/mol

Mass of H in H2O = 2/18 x 10.06 = 1.12g

For Oxygen, O:

Mass of O = 13.42 – (10.05 + 1.12) = 2.25g

Step 3:

Determination of the empirical formula for estriol. This is illustrated below:

C = 10.05g

H = 1.12g

O = 2.25g

Divide by their molar mass

C = 10.05/12 = 0.8375

H = 1.12/1 = 1.12

O = 2.25/16 = 0.1406

Divide by the smallest i.e 0.1406

C = 0.8375/0.1406 = 6

H = 1.12/0.1406 = 8

O = 0.1406/0.1406 = 1

Therefore, the empirical formula for estriol is C6H8O

Step 4:

Determination of the molecular formula for estriol. This is illustrated below:

Molecular formula is simply a multiple of the empirical formula i.e

Molecular formula => [C6H8O]n

[C6H8O]n = 288.38g/mol

[(12x6) + (8x1) + 16]n = 288.38

[72 + 8 + 16]n = 288.38

96n = 288.38

Divide both side by 96

n = 288.38/96 = 3

Molecular formula => [C6H8O]n

=> [C6H8O]n

=> [C6H8O]3

=> C18H24O3

Therefore, the molecular formula for estriol is C18H24O3

The compound is C18H24O3.

From the information in the question;

Mass of C = 36.86 g/44 g/mol × 12 g/mol = 10.1 g

Number of moles of carbon = 10.1 g/12 g/mol = 0.84 moles

Mass of hydrogen = 10.06 g/18 g/mol × 2 g/mol = 1.11 g

Number of moles of hydrogen = 1.11 g/1g/mol = 1.11 moles

Mass of oxygen = 13.42 - (10.1 g + 1.11 g) = 2.21 g

Number of moles of oxygen = 2.21g/16 g/mol = 0.14 moles

Dividing through by the lowest number of moles;

C - 0.84 moles/0.14 moles   H -  1.11 moles/0.14 moles   O - 0.14 moles/0.14 moles

C - 6   H - 8    O -1

The empirical formula is C6H8O

The molecular formula of the compound is;

[6(12) + 8(1) + 16]n = 288.38

n =  288.38/86 =3

The compound is C18H24O3

Learn more about molecular formula:https://brainly.com/question/8073802

In the first 15.0 s of the reaction, 1.7×10−2 mol of O2 is produced in a reaction vessel with a volume of 0.440 L . What is the average rate of the reaction over this time interval?

Answers

Answer:

[tex]Rate=2.57x10^{-3}\frac{M}{s}[/tex]

Explanation:

Hello,

In this case, for the reaction:

[tex]2N_2O(g) \rightarrow 2N_2(g)+O_2(g)[/tex]

We can easily compute the average rate by firstly computing the final concentration of oxygen:

[tex][O_2]=\frac{0.017mol}{0.440L}=0.0386M[/tex]

Then, we compute it by using the given interval of time: from 0 seconds to 15.0 seconds and concentration: from 0 M to 0.0386M as oxygen is being formed:

[tex]Rate=\frac{0.0386M-0M}{15.0s-0s}\\ \\Rate=2.57x10^{-3}\frac{M}{s}[/tex]

Regards.

The average rate of the reaction will be "[tex]2.57\times 10^{-3} \ M/s[/tex]".

According to the question,

Volume = 0.440 LTime = 15.0 sMol of O₂ = 1.7×10⁻²

The reaction will be:

[tex]2 N_2 O (g) \rightarrow 2 N_2 (g) +O_2 (g)[/tex]

Now,

The final concentration of O₂ will be:

→ [tex][O_2] = \frac{0.017}{0.440}[/tex]

          [tex]= 0.0386 \ M[/tex]

hence,

The rate of reaction will be:

= [tex]\frac{0.0386-0}{15.0-0}[/tex]

= [tex]2.57\times 10^{-3} \ M/s[/tex]

Thus the above approach is right.

Learn more about volume here:

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Given a gas whose temperature is 418 K at a pressure of 56.0 kPa. What is the pressure of the gas if its Temperature changes to 64°C?

Answers

Answer: P₂=0.44 atm

Explanation:

For this problem, we are dealing with temperature and pressure. We will need to use Gay-Lussac's Law.

Gay-Lussac's Law: [tex]\frac{P_{1} }{T_{1} } =\frac{P_{2} }{T_{2} }[/tex]

First, let's do some conversions. Anytime we deal with the Ideal Gas Law and the different laws, we need to make sure our temperature is in Kelvins. Since T₂ is 64°C, we must change it to K.

64+273K=337K

Now, it may be uncomfortable to use kPa instead of atm, so let's convert kPa to atm.

[tex]56.0kPa*\frac{1000Pa}{1kPa} *\frac{atm}{101325Pa} =0.55atm[/tex]

Since our units are in atm and K, we can use Gay-Lussac's Law to find P₂.

[tex]P_{2} =\frac{T_{2} P_{1} }{T_{1} }[/tex]

[tex]P_{2}=\frac{(337K)(0.55atm)}{418K}[/tex]

P₂=0.44 atm

The proposed mechanism for a reaction is: Step 1: A + B X (fast) Step 2: X + C Y (slow) Step 3: Y D (fast) What is the overall reaction? A. A + B + C D B. A + X Y + D C. A + B Y D. A + Y D

Answers

Answer:

A. A + B + C --> D

Explanation:

Step 1: A + B --> X (fast)

Step 2: X + C --> Y (slow)

Step 3: Y --> D (fast)

To obtain the overall reaction, we have to sum up the reactants and products of all step and eliminate the intermediates.

Reactants:

A + B + X + C + Y

Products:

X + Y + D

So we have;

A + B + X + C + Y  --> X + Y + D

Upon elimination of intermediates, we have;

A + B + C --> D

The correct option is A.

A certain mass of carbon reacts with 9.53 g of oxygen to form carbon monoxide. ________ grams of oxygen would react with that same mass of carbon to form carbon dioxide, according to the law of multiple proportions.

Answers

Answer: 9.53 *2= 19.06

Explanation:

The law of multiple proportions states that if two elements combines to form more than one compound the ratio of masses of the second element which combines to the fixed mass of the first element will always be the ratios of the small whole numbers.

in case of carbon monoxide, mass of carbon will be the same of mass of oxygen.

But in case of carbon dioxide, if carbon is 9.53 units then oxygen will be twice as that of carbon.

CO2, so 9.53*2= 19.06 grams of oxygen will combine with 9.53 grams of carbon to form carbon dioxide.

ii)

An organic liquid having carbon, hydrogen, nitrogen and oxygen was found to

contain C = 41.37%; H = 5.75% ; N= 16.09 % and the rest oxygen. Calculate

the Empirical formula

(6 marks)

Answers

Answer:

C3H5NO2

Explanation:

C = 41.37%;

H = 5.75% ;

N= 16.09 %;

O= (100 - 41.37 - 5.75 - 16.09)% = 36.79 %.

In 100 g of substance we have

C = 41.37 g;

H = 5.75 g ;

N= 16.09 g;

O = 36.79 g.

Molar mass (C) = 12 g/mol;

Molar mass(H) =1 g/mol;

Molar mass(N)= 14 g/mol;

Molar mass(O) = 16 g/mol.

C = 41.37 g* 1 mol/12g = 3.4475 mol;

H = 5.75 g *1 mol/1g = 5.75 mol;

N= 16.09 g*1mol/14g = 1.1493 mol;

O = 36.79 g* 1mol/16g = 2.2994 mol.

The Empirical formula shows ratio of moles of elements in the substance , so

C : H : N : O = 3.4475 mol : 5.75 mol : 1.1493 mol : 2.2994 mol =

= (3.4475 mol /1.1493 mol) : (5.75 mol/1.1493 mol) : (1.1493 mol /1.1493 mol) :   :( 2.2994 mol/1.1493 mol) = 3 : 5 : 1 : 2

C : H : N : O = 3 : 5 : 1 : 2

C3H5NO2

This ether can, in principle, be synthesized by two different combinations of haloalkane and metal alkoxide. Draw the combination of alkyl chloride and potassium alkoxide that forms the higher yield of ether. You do not have to consider stereochemistry. You do not have to explicitly draw H atoms. Include counter-ions, e.g., Na , I-, in your submission, but draw them in their own separate sketcher. Separate multiple reactants using the sign from the drop-down menu.

Answers

Answer:

The 2 different combinations are given in the attached figure. The 2nd combination has a higher yield due to less hindrance by the alkyl halide.

Explanation:

The first reaction is between an alkyl halide and metal alkoxide. In this case, the alkyl chloride would be a secondary component and thus will cause greater hindrance to the yield.  The reaction is as given in the attached figure

The second reaction is between a benzene ring containing halide and metal alkoxide. Now as the reaction is via alkyl chloride being the primary agent, there is less hindrance and thus greater yield in this case.

A glass flask has a volume of 500 mL at a temperature of 20° C. The flask contains 492 mL of mercury at an equilibrium temperature of 20°C. The temperature is raised until the mercury reaches the 500 mL reference mark. At what temperature does this occur? The coefficients of volume expansion of mercury and glass are 18 ×10-5 K-1 (mercury) and 2.0 ×10-5 K-1 (glass).

Answers

Answer:

101.63° C

Explanation:

Volume expansivity γa = γr -  γ g = 18 × 10⁻⁵ - 2.0 × 10⁻⁵ = 16 × 10⁻⁵ /K

v₂ - v₁ / v₁θ = 16 × 10⁻⁵ /K

(500 - 492 ) mL / (492 × 16 × 10⁻⁵) = θ

θ = 101.63° C

Why polythene bags create big problem in garbage disposal ?

Answers

Answer:

Polythene bags are so lightweight and aerodynamic, they are easily picked up and carried by the wind. They can escape from trash bins, recycle bins, garbage trucks, and landfills, and end up littering the landscape.

hope it helps

Explanation:

When solutions of and are mixed, the mixture becomes cloudy. After a few days, a white solid is observed on the bottom of the beaker with a clear liquid above it. (a) Write a balanced equation for the reaction that occurs. (b) Why is the solution cloudy at first

Answers

Answer:

(a) [tex]BaCl_2(aq)+Na_2SO_4(aq)\rightarrow BaSO_4(s)+2NaCl(aq)[/tex]

(b) The particles of the formed barium sulfate remain suspended in the aqueous media forming a colloid.

Explanation:

Hello,

In this case, when solutions of barium chloride and sodium sulfate are mixed, the following chemical reaction is carried out:

[tex]BaCl_2(aq)+Na_2SO_4(aq)\rightarrow BaSO_4(s)+2NaCl(aq)[/tex]

Thus, we can notice that the product barium sulfate remains solid since its solubility in aqueous media is very low, for that reason at the beginning the solution becomes cloudy as its particles remain suspended in the water forming a colloid. Nevertheless, after some days, the suspended particles get precipitated by the effect of the gravity, therefore, we observe the solid on the bottom of the beaker.

Regards.

Which spheres of earth are represented in tropical rainforests?

Answers

Answer:

Biosphere

Explanation:

because of the rain it gets from huge water sources.

I hope that was useful.

all compounds are neutral true or false​

Answers

Answer:

Even all compounds are neutral.

Explanation:

Some of them exhibit polarity. Because of the difference in electron affinity of the constituent atoms, the shared electrons are pulled towards the atom with high affinity to electrons.

The water in a pressure cooker boils at a temperature greater than 100°C because it is under pressure. At this higher temperature, the chemical reactions associated with the cooking of food take place at a greater rate. (a) Some food cooks fully in 7.00 min in a pressure cooker at 113.0°C and in 49.0 minutes in an open pot at 100.0°C. Calculate the average activation energy for the reactions associated with the cooking of this food. kJ mol-1 (b) How long will the same food take to cook in an open pot of boiling water at an altitude of 10000 feet, where the boiling point of water is 89.8 °C? min

Answers

Answer:

the activation energy Ea = 179.176 kJ/mol

it will take  7.0245 mins for the same food to cook in an open pot of boiling water at an altitude of 10000 feet.

Explanation:

From the given information

[tex]T_1 = 100^0 C = 100+273 = 373 \ K \\ \\ T_2 = 113^0 C = 113 + 273 = 386 \ K[/tex]

[tex]R_1 = \dfrac{1}{7}[/tex]

[tex]R_2 = \dfrac{1}{49}[/tex]

Thus; [tex]\dfrac{R_2}{R_1} = 7[/tex]

Because at 113.0°C; the rate is 7 time higher than at 100°C

Hence:

[tex]In (7) = \dfrac{Ea}{8.314}( \dfrac{1}{373}- \dfrac{1}{386})[/tex]

1.9459 = [tex]\dfrac{Ea}{8.314}* 9.0292 *10^{-5}[/tex]

[tex]1.9459*8.314 = Ea * 9.0292*10^{-5}[/tex]

[tex]16.1782126= Ea * 9.0292*10^{-5}[/tex]

[tex]Ea = \dfrac{16.1782126}{ 9.0292*10^{-5}}[/tex]

Ea = 179.176 kJ/mol

Thus; the activation energy Ea = 179.176 kJ/mol

b)

here;

[tex]T_2 = 386 \ K \\ \\T_1 = (89.8 + 273)K = 362.8 \ K[/tex]

[tex]In(\dfrac{R_2}{R_1})= \dfrac{Ea}{R}(\dfrac{1}{T_1}- \dfrac{1}{T_2})[/tex]

[tex]In(\dfrac{R_2}{R_1})= \dfrac{179.176}{8.314}(\dfrac{1}{362.8}- \dfrac{1}{386})[/tex]

[tex]In (\dfrac{R_2}{R_1}) = 0.00357[/tex]

[tex]\dfrac{R_2}{R_1}= e^{0.00357}[/tex]

[tex]\dfrac{R_2}{R_1}= 1.0035[/tex]

where ;

[tex]R_2 = \dfrac{1}7{}[/tex]

[tex]R_1 = \dfrac{1}{t}[/tex]

Now;

[tex]\dfrac{t}{7}= 1.0035[/tex]

t = 7.0245 mins

Therefore; it will take  7.0245 mins for the same food to cook in an open pot of boiling water at an altitude of 10000 feet.

a). The activation energy given by the reactions related to the cooking of food in the pressure cooker would be:

[tex]Ea = 179.176 kJ/mol[/tex]

b). The time duration that is taken by the same food to cook in an open vessel would be:

[tex]7.0245 mins[/tex]

Activation Energy

a). Given that,

Temperature [tex]1[/tex]  [tex]= 100[/tex]° C

Temperature [tex]2[/tex] [tex]= 113[/tex]° C

In Kelvin,

Temperature  [tex]1[/tex] [tex]= 100 + 273[/tex]

[tex]= 373 K[/tex]

Temperature  [tex]2[/tex] [tex]= 113 + 273[/tex]

[tex]= 386 K[/tex]

[tex]R_{1} = 1/7\\R_{2} = 1/49[/tex]

∵ [tex]R_{2}/R_{1} = 49/7 = 7[/tex]

It is given that at  [tex]113[/tex] rate [tex]=[/tex] [tex]7[/tex] × [tex]100[/tex]°C

Therefore,

[tex]Ea/8.314 (1/373 - 1/386) =[/tex] [tex]In(7)[/tex]

so,

[tex]Ea[/tex] [tex]= 16.1782126/(9.0292 * 10^{-5})[/tex]

Activation energy [tex]= 179.176 kJ/mol[/tex]

b). As we know,

[tex]T_{2}[/tex] [tex]= 386 K[/tex]

[tex]T_{1}[/tex] [tex]= (89. 8 + 273)[/tex]

[tex]= 362.8 K[/tex]

by employing the formulae,

[tex]In(\frac{R_{2} }{R_{1} }) = \frac{Ea}{R} (1/T_{1} - 1/T_{2})[/tex]

[tex]In(\frac{R_{2} }{R_{1} }) = 179.176/8.314 (1/362.8 - 1/386)[/tex]

By solving this, we get

[tex]R_{2}/R_{1} = 1.0035[/tex]

Thus,

[tex]R_{2} = 1/7[/tex]

[tex]R_{1} = 1/t[/tex]

∵ t [tex]= 7.0245 min[/tex]

Thus, the time duration would be [tex]7.0245 minutes[/tex].

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When 1-iodo-1-methylcyclohexane is treated with NaOCH2CH3 as the base, the more highly substituted alkene product predominates. When KOC(CH3)3 is used as the base, the less highly substituted alkene predominates. Give the structures of the two products and offer an explanation.

Answers

Answer:

See explanation

Explanation:

In this case, we have 2 types of reactions. [tex]CH_3CH_2ONa[/tex] is a strong base but only has 2 carbons therefore we will have less steric hindrance in this base. So,  the base can remove hydrogens that are bonded on carbons 1 or 6, therefore, we will have a more substituted alkene (1-methylcyclohex-1-ene).

For the  [tex]KOC(CH_3)_3[/tex] we have more steric hindrance. So, we can remove only the hydrogens from carbon 7 and we will produce a less substituted alkene (methylenecyclohexane).

See figure 1

I hope it helps!

What is the purpose of a buffer?
A. To limit pH changes in solution
B. To force the pH of a solution to change
C. To make a solution form a salt
O D. To neutralize the pH of a solution

Answers

Answer:

To limit pJ changes in solution

Tubes through which water flows as it is brought from 0.8 MPa, 150C to 240C at essentially constant pressure in the boiler of a power plant. The total mass flow rate of the water is 100 kg/s. Combustion gases passing over the tubes cool from 1067 to 547C at essentially constant pressure. The combustion gases can be modeled as air as an ideal gas. There is no significant heat transfer from the boiler to its surroundings. Surrounding (dead state) temperature and pressure are given as 25C and 1 atm, respectively. Determine i) the exergetic efficiency of the boiler ii) rate of exergy destruction as kW iii) mass flow rate of the combustion gases as kg/s

Answers

Answer:

The correct answer is i) 50.2 % ii) 13440.906 kW and iii) 71.986 kg/s.

Explanation:

In order to find the mass flow rate of the combustion of gases, there is a need to use the energy balance equation:  

Mass of water × specific heat of water (T2 -T1)w = mass of gas × specific heat of gas (T2-T1)g

100 × 4.18 × [(240 + 273) - (150 + 273)] = mass of gas × 1.005 × [(1067+273) - (547+273)]

Mass of gas = 71.986 kg/s

The entropy generation of water can be determined by using the formula,  

(ΔS)w = mass of water × specific heat of water ln(T2/T1)w

= 100 × 4.18 ln(513/423)

= 80.6337 kW/K

Similarly the entropy generation of water will be,

(ΔS)g = mass of gas × specific heat of gas ln(T2/T1)g

= 71.986 × 1.005 ln (820/1340)

= -35.53 kW/K

The rate of energy destruction will be,  

Rate of energy destruction = To (ΔS)gen

= T₀ [(ΔS)w + (ΔS)g]

= (25+273) [80.6337-53.53)

Rate of energy destruction = 13440.906 kW

The availability of water will be calculated as,  

= mass of water (specific heat of water) [(T₁-T₂) -T₀ ln T₁/T₂]

= 100 × 4.8 [(513-423) - 298 ln 513/423]

= 13591.1477 kW

The availability of gas will be calculated as,  

= mass of gas (specific heat of gas) [(T₁-T₂) - T₀ ln T₁/T₂]

= 71.986 × 1.005 × [(1340-820) - 298 ln 1340/820]

= 27031.7728 kW

The exergetic efficiency can be calculated as,  

= Gain of availability / loss of availability  

= 13591.1477/27031.7728

= 0.502

The exergetic efficiency is 50.2%.  

Write the electron configuration for the element titanium, Ti.
Express your answer in condensed form in the order of orbital filling as a string without blank space between orbitals. For example, the electron configuration of Li could be entered as 1s^22s^1 or [He]2s^1.

Answers

Answer:

[tex][Ar] 3d^{2} 4s^{2}[/tex]

Explanation:

You can look at the periodic table and figure out the electron config.

In the diagram below, particles of the substance are moving from the liquid phase to the gas phase at the same rate as they move from the gas phase to the liquid phase. A number of balls are loosely packed in the bottom of a container, beneath a line across the middle of the container, and a few balls above the line. 2 balls below the line have arrows pointing upward through the centerline; a few of the balls above the line have arrows pointing down through the centerline. The gas and liquid are at equilibrium. a high vapor pressure. a low vapor pressure. zero vapor pressure.

Answers

Answer:

The gas and liquid is in equilibrium.

Explanation:

liquids within a container undergoes state change, changing into gas. If this container is left open, these gases will escape into the external environment. In a situation in which the container is closed, the molecules that leave the liquid surface as gas will eventually condense on contact with the cover wall and change back into the liquid state. Some of these gases will reenter the liquid surface. At first, more of the liquid is transformed into gas and escape into the space above the liquid surface. Eventually, the available space becomes saturated with vapor, and then some of the gases start entering the liquid phase at the same rate as the liquid enters the gas phase. At this stage, the gas and liquid phase now exists in equilibrium.

An empty beaker is weighed and found to weigh 23.1 g. Some potassium chloride is then added to the beaker and weighed again. The second weight is 24.862 g. What is the mass of the potassium chloride

Answers

Answer:Mass of Potassium chloride =1.762g

Explanation:

Mass of empty beaker = 23.100 g

Mass of beaker with Potassium chloride = 24.862g

Mass of Potassium chloride = Final weight - initial weight = Mass of beaker with Potassium chloride  - Mass of empty beaker = 24.862-23.100 = 1.762g

Which phrase describes one characteristic of radioactive elements?
are produced in a laboratory
O decay at a constant rate
O have a consistent number of particles
release energy and particles to maintain radioactivity

Answers

Answer:

B) decay at a constant rate

Explanation:

Over their lifetime, the radioactive elements tend to have constant rate of decay. This is seen in chemistry in Kinetics, where we see that radioactive elements follow first order kinetics where the rate at which they decay is constant (no matter what concentration we have)

Answer:

B) decay at a constant rate

Explanation:

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Which of the following would describe a spontaneous process? (Select all that apply.) ΔGreaction < 0 ΔSuniverse < 0 ΔSuniverse > 0 ΔHreaction > 0 ΔHreaction < 0 ΔGreaction > 0

Answers

Answer:

ΔGreaction < 0

ΔSuniverse > 0

ΔHreaction < 0

Explanation:

A spontaneous process is one which can proceed without additional input of energy releasing free energy in the process and then moves to a lower more stable thermodynamical state.

For an isolated system, a spontaneous process proceeds with an increase in entropy.

The conditions for a spontaneous process at constant temperature and pressure, can be determined using the change in Gibbs free energy, which is given by: ∆G = ∆H - T∆S

Where ∆G is change in free energy; ∆H is change in enthalpy or Heat content; ∆S is change in entropy, T is temperature.

For a process to be spontaneous, the following conditions are necessary:

1. ∆G < 0; must be negative

2. ∆S > 0; there must be an increase in entropy

3. ∆H < 0; enthalpy change must be negative such that heat is lost to the surroundings

The above conditions ensures that ∆G is negative and the process is spontaneous.

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Answers

Answer:

B. None of these

Explanation:

Sulfur has less ionization energy than phosphorus because sulfur has a pair of electron in its 3p subshell that increases electron repulsion in sulfur and sulfur electrons can easily remove from its sub-level.

While, there are no electron pairs in 3p subshell of phosphorus, therefore it requires more energy to remove an electron from 3p subshell.

Hence, the reason is electron repulsion and the correct answer is B.

A weather balloon is inflated to a volume of 27.6 L at a pressure of 755 mmHg and a temperature of 29.9 ∘C. The balloon rises in the atmosphere to an altitude where the pressure is 385 mmHg and the temperature is -14.1 ∘C. Assuming the balloon can freely expand, calculate the volume of the balloon at this altitude.

Answers

Answer: The volume of the balloon at this altitude is 46.3 L

Explanation:

Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law

The combined gas equation is,

[tex]\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]

where,

[tex]P_1[/tex] = initial pressure of gas = 755 mm Hg

[tex]P_2[/tex] = final pressure of gas (at STP) = 385 mm Hg

[tex]V_1[/tex] = initial volume of gas = 27.6 L

[tex]V_2[/tex] = final volume of gas = ?

[tex]T_1[/tex] = initial temperature of gas = [tex]29.9^0C=(29.9+273)K=302.9K[/tex]

[tex]T_2[/tex] = final temperature of gas = [tex]-14.1^0C=((-14.1)+273)K=258.9K[/tex]

Putting all the values we get:

[tex]\frac{755\times 27.6}{302.9}=\frac{385\times V_2}{258.9}[/tex]

[tex]V_2=46.3L[/tex]

Thus the volume of the balloon at this altitude is 46.3 L

Benny Beaver wants to determine what dyesare present in his favorite sports drink. He analyzesa sample witha UV-visiblespectrophotometer and sees absorbance peaks at 415.2nm and 519.6nm. What colordyesare present in his drink

Answers

Answer:

At 415.2nm and 519.6nm, the dyes observed by the instrument are violet and green respectively.

Explanation:

In the electromagentic spectrum, visible wavelengths cover a range from approximately 400 to 800 nm. The colours of the spectrum range from red to violet (Red, Orange, Yellow, Green, Blue, Indigo and violet: a.k.a ROGBIV), in order of decreasing wavelength.

I hope this explanation would suffice.

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