Chapter 13
The Transfer of Heat
Transfer of heat from one point to another
1) Convection
2) Conduction
3) Radiation
Transfer of heat from one point to another
1) Convection
Convection and Conduction
both need medium
2) Conduction
(
kA∆T )t
Q=
3) Radiation
L
Q = eσ T At
4
σ = 5.67 ×10 −8 J (s ⋅ m 2 ⋅ K 4 )
Stefan-Boltzmann constant
The emissivity e is a dimensionless
number between zero and one
Problem 10:
A wall in a house contains a single window. The window consists of a single pane of glass whose
area is 0.16 m2 and whose thickness is 2 mm. Treat the wall as a slab of the insulating material
Styrofoam whose area and thickness are 18 m2 and 0.10 m, respectively. Heat is lost via conduction
through the wall and the window. The temperature difference between the inside and outside is
the same for the wall and the window. Of the total heat lost by the wall and the window, what is
the percentage lost by the window?
Problem 20:
Light bulb 1 operates with a filament
temperature of 2700 K, whereas light bulb 2
has a filament temperature of 2100 K. Both
filaments have the same emissivity, and both
bulbs radiate the same power. Find the ratio
A1/A2 of the filament areas of the bulbs.
Problem 42:
A copper rod has a length of 1.5 m and a cross-sectional area of 4.0 × 10-4 m2.
One end of the rod is in contact with boiling water and the other with a mixture
of ice and water. What is the mass of ice per second that melts? Assume that
no heat is lost through the side surface of the rod.
Chapter 14
The Ideal Gas Law and Kinetic Theory
1 u = 1.6605 ×10 −27 kg
n=
𝑃𝑃 = 𝑛𝑛𝑛
R = 8.31 J (mol ⋅ K )
N
NA
𝑂𝑂
N A = 6.022 ×10 23 mol−1
𝑃𝑃 = 𝑁𝑁𝑁
k = 1.38 ×10 −23 J K
Constant T, constant n:
Pf V f = PiVi
Constant P, constant n:
Vf
Vi
=
T f Ti
Boyle’s law
Charles’ law
2
KE = 12 mvrms
= 32 kT
Internal Energy
U = N 32 kT = 32 nRT
For Practice
Ch. 14
FOC 1, 3, 6, 7 & 8.
Problems 3, 10, 16, 18, 39 & 57.
Problem 10:
A cylindrical glass of water (H2O) has a radius of 4.50 cm and a height
of 12.0 cm. The density of water is 1.00 g/cm3. How many moles of
water are contained in the glass?
Problem 18:
The volume of an ideal gas is held constant. Determine the
ratio P2/P1 of the final pressure to the initial pressure when
the temperature of the gas rises
(a) from 35 to 70 K and
(b) from 35 to 70 oC.
Problem 57:
Initially, the translational rms speed of a molecule of an ideal gas is
463 m/s. The pressure and volume of this gas are kept constant,
while the number of molecules is doubled. What is the final
translational rms speed of the molecules?