Chapters 21-22 Physics Flashcards
(25 cards)
WHAT ARE THE MACRO/MICRO PROPERTIES OF A SOLID?
it has a defined shape and a fiXed volume; there are strong forces of attraction and a short separation between the particles
WHAT ARE THE MACRO/MICRO PROPERTIES OF A LIQUID?
it has a fixed volume but not a defined shape; the particles are close together (but less than in a solid) and the forces of attraction are weaker than in a solid
WHAT ARE THE MACRO/MICRO PROPERTIES OF A GAS?
it has no fixed volume nor defined shape; the particles are far away from each other and there are no forces of attraction
WHY DO WE NEED MORE ENERGY TO CONVERT A SOLID INTO A GAS THAN TO CONVERT A SOLID INTO A LIQUID?
because the bonds between the particles are being broken, not just weakened
DEFINE ‘LATENT HEAT’
the latent heat is the energy required per unit mass of a substance to raise the temperature
STATE THE ZEROTH LAW OF THERMODYNAMIC
if object A is in thermal equilibrium with object B, and object B is in thermal equilibrium with object C, then object A must be in thermal equilibrium with object C
STATE A FEW METHODS OF HEAT TRANSFER
conduction (works with all materials), convection (the flow of heated particles in a fluid), radiations (works with no material)
STATE THE FIRST LAW OF THERMODYNAMIC
energy is always conserved
WHAT’S AN ISOBARIC PROCESS?
it’s when the pressure remains constant
WHAT’S AN ADIABATIC PROCESS?
it’s when no energy leaves or enters the system as heat
WHAT’S AN IDEAL GAS?
it’s a perfect model of a gas; it doesn’t really exist but we can get an accurate prediction of what it does
WHAT’S MEANT BY BROWNIAN MOTION?
the brownian motion is the erratic motion of the particles, and it provides evidence of the fast and random movement of molecules in a gas
WHAT’S THE ABSOLUTE ZERO?
it’s when the particles have no kinetik/vibrational energy (-273°C) but it doesn’t exist in nature
WHAT’S TEMPERATURE?
temperature is the measure of the kinetik/vibrational energy of the particles
WHAT’S PRESSURE?
pressure is the result of the collisions of the air molecules with the walls of a box, with your body etc.
WHAT’S THE VOLUME?
the volume is the space occupied
STATE BOYLE’S LAW
at constant temperature, the pressure is inversely proportional to the volume (p1 x v1 = p2 x v2)
STATE CHARLES’ LAW
at constant pressure, temperature is directly proportional to the volume (T1 : v1 = T2 : v2)
STATE GAY LUSSAC’S LAW
at constant volume, pressure is directly proportional to temperature
WHAT’S A HEAT ENGINE?
a heat engine is a device that takes in energy as heat and partially converts it into work
WHAT’S A HEAT PUMP?
a heat pump is a device that pumps heat from cold to hot
STATE THE SECOND LAW OF THERMODYNAMIC
no heat engine operating in a cycle can absorb energy from a reservoir and use it entirely for the performance of an equivalent amount of work (=nothing is 100% efficient)
DEFINE ENTROPY
entropy is the measure of chaos and disorder, which increases in all natural processes. if the laws of nature are allowed to act without interference a disorderly arrangement is much more probable than an orderly one
STATE THE THIRD LAW OF THERMODYNAMIC
it’s impossible for any process, no matter how idealised, to reduce the entropy of a system to its absolute-zero value in a finite number of operations
