Question

2kg Water vapour 100°C is condensed to water at 40'C. The quantity of heat released is
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Answer 1

Answer:

Mass of the steam = 2kg

At 100℃

L     =    540cal/g.

⇒   = 54000cal/kg.

steam                      water

T = 100℃     →     T = 100℃

                     Q1            ↓Q2

                                     Water

                                     T = 40℃

Q1  =   mL

⇒   = 2 ×54000

⇒   = 108000cal

△T  = 100- 40

⇒    =600

∴ Q12 = ms△T

⇒        = 2×1×100×60

⇒        = 12000cal.

Energy evolved :

⇒        = Q1+Q2

⇒        = 12000+108000

⇒        = 120000cal

⇒        = 1200kcal.