Question

200g of ice at -20°C is mixed with 500g of water at 20°C in an insulating vessel. Final mass of water in vessel is

Answer 1

According to the circumstances mentioned in the question,200g of ice at -20°C is mixed with 500g of water at 20°C in an insulating vessel.

The final mass will be 700 grams.

Because,the whole process is taking place into a insulated environment, that's why mass loss by the temperature is almost null in this situation.

Answer 2

"Solution:

$T_1 = -20^{o}C & T_2 = 20^{o}C$

Final or average temperature $= -20+\frac{20}{2} = 0$

Temperature difference average $= \frac {(20-(-20)} {2} = 20 ^{o}C$

Change in water temperature;

$20 ^{o}C - 0^{o}C = 20 ^{o}C$

Specific heat capacity of $H_20$ or water= 4.186 J/kg

And the heat is given by,

Heat $= mass \times change\quad in\quad temperature \times heat\quad capacity.$

$= 500 \times 20 \times 4.186 = 41860 Joules$

 For 200g of ice taken at $20^{o}C$,

$200 \times 334 = 66800 Joules$

334m = 41860

$m = \frac {41860} {334} = 125.33 grams;$

To find the total mass of the fluid taken;

125.33 gm + 500 = 625.33g

Answer: 625.33 gms. "