Previous in Heat and Theromdynamics Next in Heat and Theromdynamics
Question Number 75648 by Rio Michael last updated on 14/Dec/19
$$\:{A}\:{student}\:{seals}\:\mathrm{200}{g}\:{of}\:{ice}−{cold}\:{water}\:{in}\:{a}\:{glass}\:{vacuum} \\ $$$$\left({thermos}\right)\:{flask}\:{and}\:{finds}\:{that}\:{it}\:{warms}\:{up}\:{by}\:\mathrm{3}.\mathrm{5}\:{K}\:{in}\:{one}\:{hour} \\ $$$${SHC}\:{of}\:{water}\:=\mathrm{2400}\:{Jkg}^{−\mathrm{1}} {K}^{−\mathrm{1}} \\ $$$$\left.{a}\right)\:{Calculate}\:{the}\:{average}\:{rate}\:{of}\:{heat}\:{flow}\:{in}\:{the}\:{flask}\:{in}\:{watts}. \\ $$$${To}\:{check}\:{this}\:{result}\:{over}\:{a}\:{longer}\:{period},{the}\:{student}\:{fills}\:{the}\:{flask}\:{with} \\ $$$${equal}\:{amounts}\:{of}\:{ice}\:{and}\:{water}\:{all}\:{at}\:\mathrm{0}°{C},\:{and}\:{leaves}\:{it}\:{for}\: \\ $$$$\mathrm{4}\:{hours}.\:{the}\:{specific}\:{latent}\:{heat}\left({enthalpy}\right)\:{of}\:{fusion}\:{of}\:{ice}\:{is}\:\mathrm{0}.\mathrm{33}{MJg}^{−\mathrm{1}} \\ $$$$\left.{b}\right)\:{How}\:{much}\:{ice}\:{would}\:{you}\:{expect}\:{to}\:{have}\:{melted}\:{at}\:{the}\:{end}\:{of}\:{the} \\ $$$${four}\:{hours}? \\ $$