DHS 12 First Law of Thermodynamics (Tutorial Solutions)

Dunman High School 2024 Physics H2 Tutorial Topic 9: First Law of Thermodynamics For Internal Use Only lim.boonsiong@dhs.edu.sg 1 Suggested Answers 1. 10.0 g of ice at –10 oC are introduced into 100 g of water at 50 oC contained in a copper calorimeter with a mass of 50.0 g. Calculate the final temperature reached. (specific latent heat of ice = 0.34 × 106 J kg−1 specific heat capacity of ice = 2.09 × 103 J kg−1 K−1 specific heat capacity of copper = 380 J kg−1 K−1 specific heat capacity of water = 4200 J kg−1 K−1) [38.1oC]    o oheat abs b A orbed ( by i e ce h fr e o u m ssume the heat exchang wit th s rr 10 C to 0 C by i u i ce to m o nding is negligible. Let the f elt by wate r r from melted ice t e e o reac nal temp ratu ( t be u . hea s p i h pl ) ed                                                     3 3 3 6 3 2 3 2 o 3 3 10.0 10 2.09 10 10 10.0 10 0.34 10 10.0 10 4200 0 2.09 10 3.40 10 42 4.39 10 50 38.13 C y water to reach by calorimeter to reach ) 100 10 4200 50 50.0 10 380 50         2. 1 kg of vegetables, having a specific heat capacity 2200 J kg−1 K−1, at a temperature of 373 K are plunged into a mixture containing some ice and 1 kg of water at 273 K. After all the ice has melted, the final temperature of the entire mixture is 300 K. Calculate the mass of ice originally present. Assume no heat loss to the container and the surroundings. Specific latent heat of fusion of ice = 3.34×105 J kg−1 [0.105 kg] (Assuming the ice point is at 273 K.)            5 Let the mass of ice be kg. heat absorbed by (ice to melt water from melted ice 1 kg of water) 3.34 10 1 4200 300 273 0.105 kg heat supplied by vegetables 1 2200 373 300 m m m m           

Dunman High School 2024 Physics H2 Tutorial Topic 9: First Law of Thermodynamics For Internal Use Only lim.boonsiong@dhs.edu.sg 2 3. A thermally insulated vessel containing liquid water and water vapour is connected to a vacuum pump which removes water vapour continuously. When the temperature reaches 0 oC, the vessel contains 110 g of liquid water. What mass of ice has been formed when no liquid remains? Specific latent heat of fusion of water = 3.40×105 J kg−1; Specific latent heat of vaporisation of water 1= 2.52×106 J kg−1 (at 0.01 oC) [96.9 g] Let mice (in kg) be the mass of the ice formed, then the mass