1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
kvv77 [185]
3 years ago
9

Air is compressed from an inlet condition of 100 kPa, 300 K to an exit pressure of 1000 kPa by an internally reversible compress

or. Determine the compressor power per unit mass flow rate if the device is (a) isentropic, (b) polytropic with n =1.3, (c) isothermal
Chemistry
1 answer:
ElenaW [278]3 years ago
8 0

Answer:

(a) W_{isoentropic}=8.125\frac{kJ}{mol}

(b) W_{polytropic}=7.579\frac{kJ}{mol}

(c) W_{isothermal}=5.743\frac{kJ}{mol}

Explanation:

Hello,

(a) In this case, since entropy remains unchanged, the constant k should be computed for air as an ideal gas by:

\frac{R}{Cp_{air}}=1-\frac{1}{k}  \\\\\frac{8.314}{29.11} =1-\frac{1}{k}\\

0.2856=1-\frac{1}{k}\\\\k=1.4

Next, we compute the final temperature:

T_2=T_1(\frac{p_2}{p_1} )^{1-1/k}=300K(\frac{1000kPa}{100kPa} )^{1-1/1.4}=579.21K

Thus, the work is computed by:

W_{isoentropic}=\frac{kR(T_2-T_1)}{k-1} =\frac{1.4*8.314\frac{J}{mol*K}(579.21K-300K)}{1.4-1}\\\\W_{isoentropic}=8.125\frac{kJ}{mol}

(b) In this case, since n is given, we compute the final temperature as well:

T_2=T_1(\frac{p_2}{p_1} )^{1-1/n}=300K(\frac{1000kPa}{100kPa} )^{1-1/1.3}=510.38K

And the isentropic work:

W_{polytropic}=\frac{nR(T_2-T_1)}{n-1} =\frac{1.3*8.314\frac{J}{mol*K}(510.38-300K)}{1.3-1}\\\\W_{polytropic}=7.579\frac{kJ}{mol}

(c) Finally, for isothermal, final temperature is not required as it could be computed as:

W_{isothermal}=RTln(\frac{p_2}{p_1} )=8.314\frac{J}{mol*K}*300K*ln(\frac{1000kPa}{100kPa} ) \\\\W_{isothermal}=5.743\frac{kJ}{mol}

Regards.

You might be interested in
if you had to live near a volcano would you rather live near an explosive or nonexplosive volcano?explain.
Andreas93 [3]
Non-explosive, so I wouldn't have to worry about is exploding at a random time and I would know I was safe.
6 0
3 years ago
How do you think the invention of the microscope influenced the cell theory?
ikadub [295]
Since cells are hard to see the microscope helped them see. scientist were able to actually see cells in tissues placed under the microscope.
3 0
3 years ago
How long does it take electrons to get from the car battery to the starting motor? Assume the current is 137 A and the electrons
WARRIOR [948]

Answer:

t = 55.79 min

Explanation:

First, the problem is asking for calculate the time that it takes electrons from the battery to the motor.

The general formula to calculate time is:

<em>t = d/V (1)</em>

Where:

d: distance or length

V: speed

Now, we don't have data of speed, but we can know an expression of current density in function of the distance which is the following:

<em>J = n*q*V (2)</em>

Where:

q: charge of the particle (1.6x10^-19 C)

n: number of charge carriers per unit of volume

Current density (J) is actually current per Area so:

<em>J = I/A (3)</em>

Replacing (3) in (2) we have:

I/A = nqV

Solving for V:

<em>V = I/Anq (4)</em>

Finally, if we replace this expression in (1) we have:

<em>t = nqAd / I (5)</em>

Now, the value of n, it's not given but it can be calculated because we have mass density, molar mass and avogadro's number, so this value of "n" can be calculated using the following expression:

<em>n = D * Av / MM (6)</em>

Where:

D: mass density (kg/m³)

Av: avogadro number (6.02x10^23 atom/mol)

MM: molar mass (kg/mol)

Putting the data that we know to calculate n we have:

n = 8960 * 6.02x10^23 / 0.0635

n = 8.49x10^28 atom/m³

Now with the value of n, we can finally calculate the time:

<em>t = nqAd / I </em>

A is the area and it should be in m²: 44.6 mm² / 1x10^6 m = 4.46x10^-5 m²

d is the length in meter: 75.7 cm / 100 cm/m = 0.757 m

so replacing these data in (5):

t = 8.49x10^28 * 1.6x10^-19 * 4.46x10^-5 * 0.757 / 137

t = 3,347.63 s

But the answer is in minute so:

t = 3,347.63 / 60

<em>t = 55.79 min</em>

so the electrons takes 56 min aprox. to go from the car battery to the starting motor.

4 0
3 years ago
Which best describes an oxidizing agent?
stellarik [79]

Answer:B) a reactant that undergoes reduction

Explanation:

Oxidation reaction is defined as the reaction in which a substance looses electrons. The oxidation state of the substance increases during oxidation.

M\rightarrow M^++e^-

Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced during reduction.

N^++e^-\rightarrow N

Overall reaction: M+N^+\rightarrow M^++N

The substance M which itself gets oxidized, reduces other and is called as reducing agent. The substance N which itself gets reduced, oxidizes other and is called as oxidizing agent.

6 0
3 years ago
Read 2 more answers
A piece of sodium metal can be described as?
vlada-n [284]

Answer:

A piece of sodium metal can be described as a pure substance and an element. ... Sodium is a soft, waxy, silvery, highly reactive metal. Sodium belongs to group 1 of the periodic table and it is highly abundant in the earth's crust. Sodium can also be found in various minerals such as rock salt, feldspars and sodalite.

Explanation:

here is short description that will help u 2 understand more

Thx

6 0
3 years ago
Read 2 more answers
Other questions:
  • A neutral lithium atom has 1 valence electron. A neutral bromine atom has 7 valence electrons. A chemical reaction between the 2
    8·2 answers
  • A sample of gas weighs 10.1 g and occupies a volume of 5.65 l at 60 °c and 580 torr. Identify the gas sample.
    12·1 answer
  • How was hubble important to our understanding of galaxies
    8·1 answer
  • If an element has 12 protons and 17 neutrons, how many electrons must it have?
    5·2 answers
  • What elements mass number is 15
    12·2 answers
  • - A 300g sample of CaCO3 was heated until 10 L of CO2 was collected
    7·1 answer
  • What functional group does the molecule below have?<br><br> *two leg spider looking molecule*
    13·1 answer
  • A Punnett square is used to _______.
    5·2 answers
  • Help me with physical science
    15·1 answer
  • What could reduce the heat island effect around cities?
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!