Thermodynamics Quiz

Definitions

• Heat: Amount of thermal energy transferred between objects due to a temperature difference.
• Temperature: Measure of the average kinetic energy of particles in a substance.
• Zeroth law of thermodynamics: If two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.
• Absolute zero: The lowest possible temperature. At this point, particles have minimal kinetic energy.
• 1 kcal: Unit of heat equal to 1000 calories.
• British thermal unit (BTU): Unit of heat.
• Heat capacity C: The amount of heat required to raise the temperature of an object by 1 degree Celsius.
• Specific heat capacity: The amount of heat required to raise the temperature of 1 kilogram of a substance by 1 degree Celsius.
• Power: Rate at which work is done or energy is transferred.
• Latent heat: Heat absorbed or released during a phase change of a substance without a change in temperature.

Heat Transfer Mechanisms

• There are three different mechanisms of heat transfer: conduction, convection and radiation.

Heat Capacity

• Heat capacity depends on the type of substance and mass of the substance.
• Heat capacity is always positive.

Additional Concepts

• Sea breeze is an example of convection.
• The unit of radiated power is watt.
• Work done is zero if the force acting on an object has no component in the direction of motion.
• If heat is removed from a system, the sign of heat transfer (Q) is negative.
• Positive heat transfer means heat is added to the system.
• Vacuum in thermos bottles reduces heat transfer by conduction and convection.
• Counter-current heat exchange is a method for heat transfer, often found in organisms.
• Mechanical advantage of second-class levers is always greater than one.
• 86 °F corresponds to 30 °C
• Heat is transferred from hot objects to cold objects.
• One kcal raises the temperature of 1 kg of water by 1 °C.
• Unit of latent heat is J/kg.
• The unit of heat capacity is J/kg °C or J/kg.K
• The unit of specific heat capacity is J/kg °C or J/kg.K
• Heat capacity is positive.
• The silver film in thermos bottles reduces heat transfer by radiation.
• Heat transfer in conduction is directly proportional to the hot area.
• Perfect reflectors in heat transfer have an emissivity of one.
• All objects have an emissivity value between 0 and 1.
• Heat capacity depends on the type of substance.
• Specific heat capacity is independent of mass.
• The lowest temperature is absolute zero.
• Specific heat capacity is the amount of heat required to raise the temperature of a unit mass of a substance by 1 degree Celsius.
• Amount of heat needed to raise the temperature one degree Celsius is called heat capacity or specific heat capacity.
• Amount of heat to increase temperature of 1kg of water from 14.5 °C to 15.5 °C is 1kcal.
• Countercurrent exchange decreases heat loss.
• Objects with large heat capacity require more heat for a given increase in temperature.
• Rate of change of internal energy is called metabolic rate.

Temperature Conversion and Calculations

• Provide specific calculations for different temperature conversions.