A-student-seals-200g-of-ice-cold-water-in-a-glass-vacuum-thermos-flask-and-finds-that-it-warms-up-by-3-5-K-in-one-hour-SHC-of-water-2400-Jkg-1-K-1-a-Calculate-the-average-rate-of-heat-flow

Question Number 75648 by Rio Michael last updated on 14/Dec/19

A s t u d e n t s e a l s 200 g o f i c e - c o l d w a t e r i n a g l a s s v a c u u m

(t h e r m o s) f l a s k a n d f i n d s t h a t i t w a r m s u p b y 3.5 K i n o n e h o u r

S H C o f w a t e r = 2400 {J k g}^{- 1} K^{- 1}

a) C a l c u l a t e t h e a v e r a g e r a t e o f h e a t f l o w i n t h e f l a s k i n w a t t s .

T o c h e c k t h i s r e s u l t o v e r a l o n g e r p e r i o d, t h e s t u d e n t f i l l s t h e f l a s k w i t h

e q u a l a m o u n t s o f i c e a n d w a t e r a l l a t 0 ° C, a n d l e a v e s i t f o r

4 h o u r s . t h e s p e c i f i c l a t e n t h e a t (e n t h a l p y) o f f u s i o n o f i c e i s 0.33 {M J g}^{- 1}

b) H o w m u c h i c e w o u l d y o u e x p e c t t o h a v e m e l t e d a t t h e e n d o f t h e

f o u r h o u r s ?