1‌kg of steam at 150°C is passed from a steam chamber in to a copper coil immersed in 20litres of water. The steam condenses in the coil and is returned to the steam chamber water at 90°C. Latent heat of steam is 540cal. g−1. specific heat of the steam is 1cal. g−1.°C−1. Then, the rise in temperature of water is ________
Mass of steam, ms=1kg=1000g=103 Temperature of steam, T1=150∘C Latent heat of steam, Ls=540calg−1 c‌‌=1calg−1‌∘C−1 Heat lost by steam, Q′=mLf+msc∆t
=103×540+103×1×(150−90)
=54×104+6×104 =104(54+6)=60×104cal Heat gained by 20L water, Q′′=mw×c×∆T Mass of 20L water, mw=20kg=20×103g ∴Q"=20×103×1×∆T By the principle calorimetry, Heat lost = Heat gained 60×104=20×103×∆T ⇒‌‌∆T=‌