Two teachers enter the teacher’s lounge which is kept at a constant temperature of 70 degrees Celsius. They each pour themselves a cup of coffee at precisely the same time. The temperature of the coffee is 220 degrees Celsius. Teacher 1 adds cream (at room temperature) to her coffee. After 15 minutes Teacher 2 adds cream (at room temperature) to her coffee. (i) Use Newton’s Law of Cooling to model this situation and predict whose coffee is hotter. Would your answer change if the cream was kept in the refrigerator at50 degrees Celsius until used? How so? (ii)
Energy transfer
The flow of energy from one region to another region is referred to as energy transfer. Since energy is quantitative; it must be transferred to a body or a material to work or to heat the system.
Molar Specific Heat
Heat capacity is the amount of heat energy absorbed or released by a chemical substance per the change in temperature of that substance. The change in heat is also called enthalpy. The SI unit of heat capacity is Joules per Kelvin, which is (J K-1)
Thermal Properties of Matter
Thermal energy is described as one of the form of heat energy which flows from one body of higher temperature to the other with the lower temperature when these two bodies are placed in contact to each other. Heat is described as the form of energy which is transferred between the two systems or in between the systems and their surrounding by the virtue of difference in temperature. Calorimetry is that branch of science which helps in measuring the changes which are taking place in the heat energy of a given body.
Two teachers enter the teacher’s lounge which is kept at a constant temperature of
70 degrees Celsius. They each pour themselves a cup of coffee at precisely the same
time. The temperature of the coffee is 220 degrees Celsius. Teacher 1 adds cream (at
room temperature) to her coffee. After 15 minutes Teacher 2 adds cream (at room
temperature) to her coffee.
| (i) | Use Newton’s Law of Cooling to model this situation and predict whose coffee is hotter. Would your answer change if the cream was kept in the refrigerator at50 degrees Celsius until used? How so? |
| (ii) |
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