Fysik
tjek om opg er rigtig- termodynamik
Mrs Smith wants to prepare soup for the family’s dinner and therefore she takes a block of soup out of the refrigerator (msoup = 2 kg, trefrigerator = -18°C). She drops the block of soup into an aluminium pot (mAl pot = 0.75 kg, tstart,,Al pot = 22°C) and heat it up to 80°C on an iron hot plate (mFe hot plate = 0.60 kg, tstart, Fe hot plate = 22 °C). You may assume that the soup has the same thermodynamic properties as H2O.
1. Calculate the time required in order to reach the final temperature (tfinal = 80 °C) for the entire system when the heat exchange rate of the hotplate is 2.5 kW. (no heat is lost to the surroundings)
m = cp * (tend-t, start)
2 kg (soup) * 2,10J/kg°C * 18°C = 75,6 kj
mAL pot0,75kg * 9,00 j/kg°C 80 = 540kj
mFe Hotplate 0,60 kg * 58° * 4,50(Iron) = 156,6 kj
Total= 772,2 kj
772,2 / 2,5 = 308 sec.
Skriv et svar til: tjek om opg er rigtig- termodynamik
Du skal være logget ind, for at skrive et svar til dette spørgsmål. Klik her for at logge ind.
Har du ikke en bruger på Studieportalen.dk?
Klik her for at oprette en bruger.