A spacecraft is fueled using hydrazine (N2H4; molecular weight of 32 grams per mole [g/mol]) and carries 1640 kilograms [kg] of fuel. On a mission to orbit a planet, the fuel will first be warmed from −186 degrees Fahrenheit [°F] to 78 degrees Fahrenheit [°F] before being used after the long space flight to reach the planet. The specific heat capacity of hydrazine is 0.099 kilojoules per mole kelvin [kJ/(mol K)]. If there is 300 watts [W] of power available to heat the fuel, how long will the heating process take in units of hours [h]?

Answers

Answer 1
Answer:

The expression for thermal energy and power we were able to find the time necessary to heat the fuel is t = 689 h

To find

  • Time

The international measurement system (SI) establishes the fundamental units in the measurement processes, this is defined by convention, giving uniformity in the calculation process and measurement exchange. Before starting the exercise we must reduce the magnitude to the SI system

          PM = 32 g / mol ((1 kg)/(1000 g) g) = 32 10-3 kg / mol

          T₀ = 5/9 (ºF -32) + 273.15 = 5/9 (186 32) +273.15 = 152.0 K

          T_f = 5 * (78 - 32) +273.15 = 298.7 K

          c_e = 0.099 kj / mol k ((1000J)/(1 kJ)) = 0.099 10³ J / mol K

The mole is the amount of matter of the international system (SI), the moles exist must be calculated since they are the mass of the compound for this we use a direct rule of proportions, if a mole has more than 32 10⁻³ kg, when moles are 1640 kg

           n = (m)/(PM)

           n = 1640/32 10⁻³

           n = 51.25 10³ mol

If we assume that all energy transfer is thermal, we can use  

           Q = m\  c_e ( T_f - T_o)

           Q = 51.25 10³ 0.099 10³ (298.7 -152.0)

           Q = 7.44 10⁸ J

             

Power defined by the relationship between work and time

           P = (W)/(t)

In this case the thermal work is equal to the heat ( W=Q)

           t = (Q)/(P)

           t = 7.44 10⁸ / 300

           t = 2.48 10⁶ s

They indicate that the answer is given in hours, let's reduce the time

           t = 2.48 106 s (1h / 3600s)

           t = 6.89 10² h

In conclusion, with the relationship of thermal energy and power, we were able to set the time necessary for the amount of fuel to be t = 689 h

Learn more about thermal energy and power here:

brainly.com/question/11278589

Answer 2
Answer:

Answer:

The value is t = 689.029 \  hours

Explanation:

From the question we are told that

The molar mass of hydrazine is Z =  32 g/mol = (32)/(1000) = 0.032 \  kg/mol

The initial temperature is T_i  =  -186 ^o F = (-186-32) *(5)/(9) +273.15 = 152\ K

The final temperature is T_f  =  78 ^o F = (78-32) *(5)/(9) +273.15 = 298.7 \ K

The specific heat capacity is c_h  =  0.099 [kJ/(mol K)] = 0.099 *10^3 J/(mol/K)

The power available is P = 300 \ W

The mass of the fuel is m =   1640 \  kg

Generally the number of moles of hydrazine present is

n  =  (m)/(Z)

=> n  =  (1640)/(= 0.032)

=> n  =  51250 \ mol

Generally the quantity of heat energy needed is mathematically represented as

Q =  n * c_h * (T_f -T_i)

=> Q =  51250  * 0.099 *10^3  * (298.7 - 152)

=> Q =  7.441516913 * 10^(8) \  J

Generally the time taken is mathematically represented as

t =  (Q)/(P)

=> t =  (7.441516913 * 10^(8) )/(300)

=> t = 2480505.6377 s

Converting to hours

t = (2480505.6377)/(3600)

=> t = 689.029 \  hours


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Answers

A. Soapy solution (pH of 9) = basic
B. Sour liquid (pH of 5) = acidic
C. Solution with four times as many hydronium (H+) ions as hydroxide ions (OH-) = acidic

Soapy solution with a pH of 9 is basic because it has a pH greater than 7. The same goes for the sour liquid with a pH of 5, which has a pH lower than 7, making it acidic. The word sour also hints at it being acidic because of the definition of Bronsted acids. Finally, higher H+ ion concentrations make a solution more acidic.

Which of the following occurs when light is reflected from a rough or unpolished surface? A. The original pattern of the light is distorted.
B. The original pattern of the light is preserved.
C. The angle of reflection is less than the angle of incidence.
D. The angle of reflection is greater than the angle of incidence.

Answers

So we want to know what does occur when light is refracted from a rough and unpolished surface. The correct answer is A. the original pattern of the light is distorted because rough and unpolished surfaces dissipate light in all directions so we cant get a clear image.
The correct answer is A

In the Bohr model of the hydrogen atom, an electron moves in a circular path around a proton. The speed of the electron is approximately 2.03 106 m/s.(a) Find the force acting on the electron as it revolves in a circular orbit of radius 5.35 10-11 m.
whats the magnitude in N ?


(b) Find the centripetal acceleration of the electron.
whats the magnitude in m/s2

Answers

In order to answer these questions, we need to know the charges on
the electron and proton, and then we need to know the electron's mass. 
I'm beginning to get the creepy feeling that, in return for the generous
5 points, you also want me to go and look these up so I can use them
in calculations ... go and collect my own straw to make the bricks with,
as it were. 

Ok, Rameses:

Elementary charge . . . . .  1.6 x 10⁻¹⁹  coulomb
                                        negative on the electron
                                        plussitive on the proton

Electron rest-mass . . . . .  9.11 x 10⁻³¹  kg


a).  The force between two charges is

      F  =  (9 x 10⁹) Q₁ Q₂ / R²

          =  (9 x 10⁹ m/farad) (-1.6 x 10⁻¹⁹C) (1.6 x 10⁻¹⁹C) / (5.35 x 10⁻¹¹m)²

          =     ( -2.304 x 10⁻²⁸) / (5.35 x 10⁻¹¹)²

          =          8.05 x 10⁻⁸  Newton .


b).  Centripetal acceleration  = 

                                               v² / r  .

                  A  =  (2.03 x 10⁶)² / (5.35 x 10⁻¹¹)

                     =      7.7 x 10²²  m/s² .

That's an enormous acceleration ... about  7.85 x 10²¹  G's !
More than enough to cause the poor electron to lose its lunch.

It would be so easy to check this work of mine ...
First I calculated the force, then I calculated the centripetal acceleration.
I didn't use either answer to find the other one, and I didn't use  "  F = MA "
either.

I could just take the ' F ' that I found, and the 'A' that I found, and the
electron mass that I looked up, and mash the numbers together to see
whether  F = M A .

I'm going to leave that step for you.   Good luck !

Light traveling through air at 3.00 · 10^8 m/s reaches an unknown medium and slows down to 2.00 · 10^8 m/s. What is the index of refraction of that medium? n =

Answers

v 1= 3.00 · 10^8 m/s
v 2 = 2.00 · 10^8 m/s
The index of refraction:
n = v 1 / v 2 = 3.00 · 10^8 m/s : 2.00 · 10^8 m/s = 1.5
Answer:
The index of refraction of that medium is 1.5

Answer

The index of refraction of  medium is 1.5 .

Explanation:

Equation for  index of refraction is given by .

n = (c)/(v)

Where n is index of refraction in medium , v is speed of light in the medium and c is the speed of light in air .

As given

Light traveling through air at 3.00* 10^8 m/s reaches an unknown medium and slows down to 3.00* 10^8 m/s.

c = 3.00* 10^(8)

v = 2.00* 10^(8)

Putting the values in the formula

n = (3.00* 10^(8))/(2.00* 10^(8))

Solving the above

n = 1.5

Therefore the index of refraction of  medium is 1.5 .


Is it possible to have 400m distance and yet zero for displacement? Please explain by using an example.

Answers

Yes, If you travel in a circle that has a circumference of 400 m and you complete that four hundred metres you will end up in the same spot. Imagine a 400 m race track. You complete 1 lap you end up where you started, hence no displacement, but you have traveled 400 m

In order for an organism to develop specialized tissues the organism must be

Answers

Answer:

miuti celluar

Explanation:

Answer: It's multicellular (D)