countries, liquid nitrogen is used on dairy trucks instead of mechanical refrigerators. A 3.00-hour delivery trip requires 250 L of liquid nitrogen, which has a density of 808 kg/m3. (a) Calculate the heat needed in kilocalories to evaporate this amount of liquid nitrogen and raise its temperature to 2.50°C. (You must use cp, and you can assume it is constant over the temperature range.) This is the amount of cooling the liquid nitrogen supplies. (b) What is this in kilowatt-hours?
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.
We know that we have given that liquid nitrogen is used on dairy trucks instead of mechanical refrigerators. A 3.00-hour delivery trip requires 250 L of liquid nitrogen, which has a density of 808 kg/m3.
We know that the formula of the heat transfer and temperature change are related as
Q = mc
- where Q is the heat transfer
- m is the mass
- is the change in temperature
- c is the specific heat
We also know that heat is required to change the phase of the sample of the mass m,
Q = mL
where L is the latent heat of vaporization
Trending now
This is a popular solution!
Step by step
Solved in 4 steps
