Section C: thermodynamics Flashcards
what is the first law of thermodynamics?
energy is conserved ie. it cannot be created or destroyed
define ‘specific heat capacity’
the energy required to increase the temperature of 1g of water by 1C (= 1 calorie)
what is the relationship between calories and joules?
1 cal = 4.2 J
which combination of units is equal to 1 Coulomb?
1 C = 1 A.s
which combination of units is equal to 1 Volt?
1 V = 1 J.C^-1
what is the evidence for the first law of thermodynamics?
Joule’s Paddlewheel experiment showing the equivalence of work and heat
how is work done calculated?
E = Fx
where F = force; x = distance
define ‘specific latent heat’
the amount of energy in the form of heat required to effect a phase change in 1 kg of a substance without any change in temperature
how can the specific heat capacity be calculated from a graph of energy versus temperature?
it is equal to the gradient of the graph
what graph can be drawn to calculate the specific heat capacity?
energy versus temperature plot
what is the metabolic rate?
the rate of energy conversion ie. power dispersed
P = dE/dt
what is Kleiber’s Law?
P ∝ M^3/4
where P = metabolic rate; M = mass
what is the relationship between horsepower and Watts?
1 hp = 745.1 W
what is an open system?
exchange of energy and matter with the surroundings
what is a closed system?
exchange of energy but not of matter with the surroundings
what is an isolated system?
no exchange of energy or matter with the surroundings
what is an adiabatic system?
no exchange of heat with the surroundings
true or false: the Maxwell-Boltzmann distribution is symmetrical
false; it is asymmetrical and weighted towards lower speeds
what is the Boltzmann distribution function?
population En / population E0 = e^ -(En-E0) / kT
what is ‘k’?
Boltzmann’s constant
k = 1.38 x 10^-23 J.K^-1
what is the zeroth law of thermodynamics?
energy flows in the form of heat between objects to equalise their temperature if T(A) = T(B) and T(B) = T(C), then T(A) = T(C)
is temperature an intensive or extensive property?
intensive
define ‘intensive’ property
not additive; does not depend on the amount of material
define ‘internal energy’, U
the sum of all possible energies in the system