PHYSICS UNIT 6 HEAT AND
THERMODYNAMICS EXAM QUESTIONS
WITH CORRECT ANSWERS
coefficient of cubic expansion - ANSWER-change in volume per unit volume per degree
change in temperature
liquids have a greater/lower coefficient of volume expansion than solids? - ANSWER-
greater
what is unique about gases in terms of Thermal expansion - ANSWER-all gases have
approximately the same coefficient of expansion and is nearly constant at all
temperatures BECAUSE--> molecules are more independent of each other due to great
distances between them
Usually, volume increases when temperature increases. What is the exception to this
rule? - ANSWER-water between 0C-4C (the volume increases while temperature
decreases; reason why ice floats and Titanic sunk)
heat (simple definition) - ANSWER-energy in transit
direction of flow - ANSWER-energy always travels from an object of higher temperature
to lower temperature
compare temperature, heat and internal energy - ANSWER-temperature is the measure
of AVERAGE KE; heat is the TRANSFER of KE; internal energy is the SUM of all
energies in the molecule
units for heat - ANSWER-joules or calories
SI unit of energy (heat) - ANSWER-joule
calorie - ANSWER-Non-SI unit of heat (older unit)
british thermal unit (Btu) - ANSWER-English unit; used in engineering, air conditioning,
and refrigeration (=1055 J)
therm - ANSWER-used to measure natural gas usage
thermal conduction - ANSWER-the process by which energy is transferred by heat
through a material between two points at different temperatures
, give 3 examples of conduction (answers will vary) - ANSWER-holding an ice cube,
cooking pancakes, touching a stovetop
thermal conduction happens when objects _____________ - ANSWER-touch
thermal conductors - ANSWER-substances that transfer energy rapidly
thermal insulators - ANSWER-substances that transfer energy slowly
Why do people wear layers in the winter? - ANSWER-air acts as an insulator
convection - ANSWER-uses the combined effect of conduction and buoyancy
give 3 examples of convection (answers will vary) - ANSWER-Boiling water, lava lamps,
hot air balloon
radiation - ANSWER-energy is transferred without transferring matter
specific heat capacity - ANSWER-the quantity of energy needed to raise the
temperature of 1 kg of a substance by 1C at constant pressure (J/KgC)
How do you find which material has a higher heat capacity? - ANSWER-subject two
materials to the same energy; whichever changes more has a lower specific heat
capacity
Law of heat exchange - ANSWER-any heat-transfer system the heat lost by hot
substances equals the heat gained by cold substances (heat gained= heat lost)
method of mixtures - ANSWER-technique for measuring the quantity of heat transfer
from one substance to another
another name for method of mixtures - ANSWER-calorimetry
calorimeter - ANSWER-a heat measuring device that consists of nested metal cups
separated by an air space
triple point - ANSWER-specific temperature or pressure where solid, liquid and vapor
phases of a substance can exist in contact and in thermal equilibrium
critical point - ANSWER-a temperature point where substance cannot exist as a liquid
no matter what pressure is applied
the critical point is also referred to as - ANSWER-the "upper limit"
THERMODYNAMICS EXAM QUESTIONS
WITH CORRECT ANSWERS
coefficient of cubic expansion - ANSWER-change in volume per unit volume per degree
change in temperature
liquids have a greater/lower coefficient of volume expansion than solids? - ANSWER-
greater
what is unique about gases in terms of Thermal expansion - ANSWER-all gases have
approximately the same coefficient of expansion and is nearly constant at all
temperatures BECAUSE--> molecules are more independent of each other due to great
distances between them
Usually, volume increases when temperature increases. What is the exception to this
rule? - ANSWER-water between 0C-4C (the volume increases while temperature
decreases; reason why ice floats and Titanic sunk)
heat (simple definition) - ANSWER-energy in transit
direction of flow - ANSWER-energy always travels from an object of higher temperature
to lower temperature
compare temperature, heat and internal energy - ANSWER-temperature is the measure
of AVERAGE KE; heat is the TRANSFER of KE; internal energy is the SUM of all
energies in the molecule
units for heat - ANSWER-joules or calories
SI unit of energy (heat) - ANSWER-joule
calorie - ANSWER-Non-SI unit of heat (older unit)
british thermal unit (Btu) - ANSWER-English unit; used in engineering, air conditioning,
and refrigeration (=1055 J)
therm - ANSWER-used to measure natural gas usage
thermal conduction - ANSWER-the process by which energy is transferred by heat
through a material between two points at different temperatures
, give 3 examples of conduction (answers will vary) - ANSWER-holding an ice cube,
cooking pancakes, touching a stovetop
thermal conduction happens when objects _____________ - ANSWER-touch
thermal conductors - ANSWER-substances that transfer energy rapidly
thermal insulators - ANSWER-substances that transfer energy slowly
Why do people wear layers in the winter? - ANSWER-air acts as an insulator
convection - ANSWER-uses the combined effect of conduction and buoyancy
give 3 examples of convection (answers will vary) - ANSWER-Boiling water, lava lamps,
hot air balloon
radiation - ANSWER-energy is transferred without transferring matter
specific heat capacity - ANSWER-the quantity of energy needed to raise the
temperature of 1 kg of a substance by 1C at constant pressure (J/KgC)
How do you find which material has a higher heat capacity? - ANSWER-subject two
materials to the same energy; whichever changes more has a lower specific heat
capacity
Law of heat exchange - ANSWER-any heat-transfer system the heat lost by hot
substances equals the heat gained by cold substances (heat gained= heat lost)
method of mixtures - ANSWER-technique for measuring the quantity of heat transfer
from one substance to another
another name for method of mixtures - ANSWER-calorimetry
calorimeter - ANSWER-a heat measuring device that consists of nested metal cups
separated by an air space
triple point - ANSWER-specific temperature or pressure where solid, liquid and vapor
phases of a substance can exist in contact and in thermal equilibrium
critical point - ANSWER-a temperature point where substance cannot exist as a liquid
no matter what pressure is applied
the critical point is also referred to as - ANSWER-the "upper limit"
