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3 years ago

A protostar forms once the nebular cloud condenses and the core begins

Physics

2 answers:

Fantom [35]3 years ago

6 0

A protostar forms once the nebular cloud condenses and the core begins nuclear fusion.

enyata [817]3 years ago

4 0

Answer:

Explanation:

A protostar forms once the nebular cloud condenses and the core begins HEAT.

A protostar is a very young star that is still gathering mass from its parent molecular cloud. The protostellar phase is the earliest one in the process of stellar evolution. A protostar is the earliest stage in star formation in the universe. When the gas cloud begins to collapse on its own weight, the core begins to heat up. The heat is due to the force of compression of the dust and gas under its gravity. When the pressure and temperatures become high enough, the hydrogen in the core begins to fuse.

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What change in entropy occurs when a 0.15 kg ice cube at -18 °C is transformed into steam at 120 °c 4.

Studentka2010 [4]

<u>Answer:</u> The change in entropy of the given process is 1324.8 J/K

<u>Explanation:</u>

The processes involved in the given problem are:

$1.)H_2O(s)(-18^oC,255K)\rightarrow H_2O(s)(0^oC,273K)\\2.)H_2O(s)(0^oC,273K)\rightarrow H_2O(l)(0^oC,273K)\\3.)H_2O(l)(0^oC,273K)\rightarrow H_2O(l)(100^oC,373K)\\4.)H_2O(l)(100^oC,373K)\rightarrow H_2O(g)(100^oC,373K)\\5.)H_2O(g)(100^oC,373K)\rightarrow H_2O(g)(120^oC,393K)$

Pressure is taken as constant.

To calculate the entropy change for same phase at different temperature, we use the equation:

$\Delta S=m\times C_{p,m}\times \ln (\frac{T_2}{T_1})$ .......(1)

where,

$\Delta S$ = Entropy change

$C_{p,m}$ = specific heat capacity of medium

m = mass of ice = 0.15 kg = 150 g (Conversion factor: 1 kg = 1000 g)

$T_2$ = final temperature

$T_1$ = initial temperature

To calculate the entropy change for different phase at same temperature, we use the equation:

$\Delta S=m\times \frac{\Delta H_{f,v}}{T}$ .......(2)

where,

$\Delta S$ = Entropy change

m = mass of ice

$\Delta H_{f,v}$ = enthalpy of fusion of vaporization

T = temperature of the system

Calculating the entropy change for each process:

<u>For process 1:</u>

We are given:

$m=150g\\C_{p,s}=2.06J/gK\\T_1=255K\\T_2=273K$

Putting values in equation 1, we get:

$\Delta S_1=150g\times 2.06J/g.K\times \ln(\frac{273K}{255K})\\\\\Delta S_1=21.1J/K$

<u>For process 2:</u>

We are given:

$m=150g\\\Delta H_{fusion}=334.16J/g\\T=273K$

Putting values in equation 2, we get:

$\Delta S_2=\frac{150g\times 334.16J/g}{273K}\\\\\Delta S_2=183.6J/K$

<u>For process 3:</u>

We are given:

$m=150g\\C_{p,l}=4.184J/gK\\T_1=273K\\T_2=373K$

Putting values in equation 1, we get:

$\Delta S_3=150g\times 4.184J/g.K\times \ln(\frac{373K}{273K})\\\\\Delta S_3=195.9J/K$

<u>For process 4:</u>

We are given:

$m=150g\\\Delta H_{vaporization}=2259J/g\\T=373K$

Putting values in equation 2, we get:

$\Delta S_2=\frac{150g\times 2259J/g}{373K}\\\\\Delta S_2=908.4J/K$

<u>For process 5:</u>

We are given:

$m=150g\\C_{p,g}=2.02J/gK\\T_1=373K\\T_2=393K$

Putting values in equation 1, we get:

$\Delta S_5=150g\times 2.02J/g.K\times \ln(\frac{393K}{373K})\\\\\Delta S_5=15.8J/K$

Total entropy change for the process = $\Delta S_1+\Delta S_2+\Delta S_3+\Delta S_4+\Delta S_5$

Total entropy change for the process = $[21.1+183.6+195.9+908.4+15.8]J/K=1324.8J/K$

Hence, the change in entropy of the given process is 1324.8 J/K

4 0

3 years ago

If you separate vector B into its components. How many components will it have? Those components will be called?

Inessa [10]

The vector B will have two components and those components will be called resultant vectors.

<h3>What is a component vector?</h3>

A component vector is a unit vector that represents a given vector in a particular direction.

A vector can be represented in x - direction and y - direction.

x - component of the vector = Bcosθ
y - component of the vector = Bsinθ

Thus, the vector B will have two components and those components will be called resultant vectors.

Learn more about component vectors here: brainly.com/question/13416288

#SPJ12

3 0

2 years ago

How would you respond to a person who argued that the Big Bang theory is incorrect because it is only a theory and theories have

Umnica [9.8K]

Well, you would reply that that's not what theories are. Theories explain the how and the why, laws explain the what. So, the Big Bang theory isn't "just a theory". It's a theory, it explains the how. (Also, if someone tells you it's anti-God or whatever, tell them the thoery was created by a Catholic scientist. True fact.) I hoped this helped!!! (You don't have the include who created the theory if this is for homework.)

5 0

3 years ago

Read 2 more answers

The respiratory system - 2/3

stepan [7]

The answers to the respiratory questions are listed below:

6). Trachea
7). Pneumonia
8). True
9). False
10). Hair

<h3>Meaning of a respiratory system</h3>

A respiratory system is a biological system found in both plants and animals, which includes organs and structures used for exchanging gas between the organisms and its environments.

A respiratory system is a network or chain or organs and tissues that enables breathing.

In conclusion, the respiratory system is one that is very important to understand.

Learn more about respiratory system : brainly.com/question/1270124

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3 0

2 years ago

The current in a wire varies with time according to the relationship 1=55A−(0.65A/s2)t2. (a) How many coulombs of charge pass a

mario62 [17]

Answer:

(A) Q = 321.1C (B) I = 42.8A

Explanation:

(a)Given I = 55A−(0.65A/s2)t²

I = dQ/dt

dQ = I×dt

To get an expression for Q we integrate with respect to t.

So Q = ∫I×dt =∫[55−(0.65)t²]dt

Q = [55t – 0.65/3×t³]

Q between t=0 and t= 7.5s

Q = [55×(7.5 – 0) – 0.65/3(7.5³– 0³)]

Q = 321.1C

(b) For a constant current I in the same time interval

I = Q/t = 321.1/7.5 = 42.8A.

3 0

3 years ago

Read 2 more answers