Respuesta :
Answer:
a) t = 21.72 minutes
b) Total Time = 255.47 mins
Explanation:
Given:
- Mass of ice m = 0.55 kg
- Initial Temperature T_i = -15 C
- Rate of Heat in-put W_in = 800 J /min
- Specific Heat capacity of ice c_p = 2106 J/kgK
Find:
(a) After how many minutes does the ice start to melt?
(b) After how many minutes, from the time when the heating is first started, does the temperature begin to rise above 0.0 C?
(c) Plot a curve showing the temperature as a function of the elapsed time.
Solution:
- The amount of heat required by a mass m of ice to raise its temperature from initial to T is given by the expression:
Q_in = m*c_p* ( T - T_i )
- The melting point of ice is T = 0 C
- The amount of Heat input is given by:
Q_in = W_in*t
Where, t is time in minutes
- Combine the two expressions:
t = m*c_p* ( T - T_i ) / W_in
- plug in the values to compute t:
t_1 = 0.55*2106*(0 - (-15)) / 800
t_1 = 21.72 minutes
- The amount of time it takes to raise the temperature of ice to its melting point is t = 21.72 mins.
- As soon as the ice reaches its melting point, For the temperature to rise again, it must break the inter-molecular forces between molecules and cause a phase transformation from solid to liquid. So the amount of heat required for ice to transform into water is called the latent heat of fusion. Hence,
W_in*t = m*L_f
t_2 = m*L_f / W_in
Plug values in: t_2 = 0.55*(3.4*10^5) / 800
t_2 = 233.75 mins
- Hence, the total time taken from initial temperature to the point it starts rising from 0 C is:
Total Time = t_1 + t_2
Total Time = 21.72+ 233.75
Answer: Total Time = 255.47 mins
As per question, the container holds the amount of 0.55kg ice and has a mass of the container which is to be ignored the heat is given to the container at a constant if the rate of 800.
- Mass of ice m equal to 0.55 kg
- Initial Temperature T_i = -15 C
- Rate of Heat in-put W_in = 800 J /min
- Heat capacity of ice c_p = 2106 J/kgK.
- The amount of heat required by a mass m of ice to raise its temperature from initial to T is given by the expression.
The melting point of ice is T = 0 C
Learn more about the kg of ice at -15.0 C.
brainly.com/question/14788130.
