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heat
the energy transferred from one object to another due to a difference in temperature
kinetic theory of matter
the theory which states that all matter is made up of small particles which are in constant random motion
temperature
a measure of the average kinetic energy of the particles in a given substance or system
thermal energy
the kinetic energy that comes from the vibration of particles
heat
the energy transferred from one object to another due to a difference in temperature
Solid
In its solid state, the object has the least thermal energy. The particles tend to vibrate more slowly, and the object maintains its structure
Liquid
In its liquid state, the object has more thermal energy than it did as a solid, so its particles vibrate enough to slip past each other and form a loose structure
Gas
In its gaseous state, the object has even greater thermal energy, so its particles vibrate quickly enough to escape its structure altogether.
Temperature is a measure of the average kinetic energy of the particles in a given substance or system
not the total, so it is independent of size.
Absolute zero is the temperature at which a substances particles have no vibration. Since vibration is the cause of temperature
and it is not possible to have less vibration than zero, absolute zero is the lowest temperature that there is.
Define temperature in terms of kinetic energy?
Temperature is a measure of the average kinetic energy of the atoms or molecules in a substance
A scientist put a 100 g sample of zinc and a 100 g sample of lead side by side on a hotplate for exactly the same amount of time. She then measured the temperatures of the two metals with a thermometer. The lead had a higher temperature. Explain this result
Different substances have different heat capacities, which means a different amount of energy is needed to raise their temperature by the same amount. Since the zinc had the lower temperature it must have a higher heat capacity than lead.
Temperature is defined as __________.
a measure of the average kinetic energy of the particles in the system
Study the scenario.
The particles in a system are moving around very slowly. A few minutes later, the particles are moving, on average, much faster.
How does this change in motion affect the temperature of the system?
the temperature increase since the average kinetic energy of the particles increases
Which statement correctly explains the differences in the molecular motion of solids and liquids using the kinetic theory?
Molecules move slowest in solids and faster in liquids Moving molecules store kinetic energy, so molecules in a solid state have less energy than those molecules in a liquid.
Which choice correctly describes what happens during cooling?
If two systems are at different temperatures, energy will leave the system with greater thermal energy and go into the system with less thermal energy.
phase change
the transformation of matter between solid, liquid, and gas
energy absorption
a process in which the particles in a system or object take in energy from an external source
thermal equilibrium
the point at which two adjacent systems reach the same temperature, so that the transfer of thermal energy is equal in both directions
At what point are two objects said to be at thermal equilibrium with each other?
when their temperatures are equal
Why does the temperature of an object remain the same during a phase change?
Additional energy removed or added is used up in changing solid into liquid.
During the phase change from solid to liquid, the energy absorbed is used to break the bonds holding the molecules together in a crystal structure. This causes the object to melt and become liquid, but does not result in an increase in temperature, as the average speed of vibration of the molecules does not increase.
When two objects at different temperatures are in contact, what term describes the flow of thermal energy between them?
heat
What is thermal equilibrium?
Thermal equilibrium is the point where two objects or systems have the same temperature. At this point the net transfer of heat is zero.
The amount of heat required to convert gold from a solid to a liquid is 64 kJ/kg. What is the effect of adding 50 kJ of thermal energy to 1 kg of gold that has just reached its melting temperature?
The addition of 50 kJ of thermal energy will only allow some of the gold to change from a solid to a liquid. The temperature of the gold will not change.
When the flow of heat increases the kinetic energy of the particles of an object it is known as:
heat absorption
Study the scenario:
A pizza is at thermal equilibrium with a hot tray, which is at a temperature of 150 ºF. The pizza is then moved to a refrigerator at 40 ºF. What happens to the pizza when it's moved to a place with this much lower temperature?
The pizza gives off more energy than it absorbs until it reaches a new, lower thermal equilibrium where the amount of energy absorbed and given off is the same.
