chapter 10, transfer of heat energy and its effects Flashcards
SI unit for temperate?
kelvin
what is transfer of heat
it occurs when changes occur when heat energy is transferred from a region of higher temperature to a region of lower temperature
*note- heat energy = thermal energy
what happens to the particles in an object when it is heated in it’s solid state
the particles gain energy and vibrate more vigorously about their fixed positions. the distances between the particles then increase, causing the volume of the substance to increase. As a result, the substance expands.
what happens when a substance in it’s solid state is cooled?
its particles lose energy and vibrate less vigorously about their fixed positions. the distances between these particles then decrease, causing the volume of the substance to decrease. As a result the substance contracts
What is the law of conservation of mass?
The number and size of particles in a substance do not change during expansion and contraction. Thus, there is conservation of mass.
application of expansion in liquids
climate change includes global warming, which results in oceans absorbing more heat energy. This causes oceans to expand and the sea level to rise. The rise in the sea level causes more coastal to be washed away. Thus, coastal erosion increases.
expansion and contraction in liquids and gases
metal pipes expand and contract depending on the surrounding temperature and the substances they carry. Metal pipes carrying steam or hot water are built with flexible bends. These bends enable the pipes to expand and contract safely without breaking.
applications of thermal expansion and contraction
opening a jar:
placing the lid in hot water as the metal lid would expand more than the glass jar. This makes the lid less tight and easier to unscrew.
what happens to an object when it is heated?
it’s density is decreased. as the volume increases but the mass stays the same, causing the density to decrease.
how is heat transferred through convection? (ni/cs/es)
through a fluid (liquid or gas) caused by molecular motion (movement of medium
what are the three ways of heat transfer?
condution,convection,radiation
how is heat transferred through conduction? (ni/cs/es)
the transfer of heat or electric current from one substance to another by direct contact
how is heat transferred through radiation? (ni/cs/es)
energy that is radiated or transmitted in the form of rays or waves or particles.
how do particles (atoms and molecules) transfer energy to each other?
- collisions
- one molecule collides with another molecule and passes on kinetic energy
- molecule with greater KE passes energy to the molecule with less KE
Which of state of matter expands the most when subjected to the same change in thermal energy?
solids: the particles are not free to move. Solids do not expand much
liquids: the particles move more freely than in solids. Liquids usually expand more than solids.
Gases: the particles are far apart and move more freely than in liquids. Gases usually expand more than liquids
