Topic Start | Investigation | Previous Page | Next Page

Challenge: Problem 2

Consider the diagram. An electric current in the resistance boils the liquid, and the vapour moves the small piston against the atmosphere. Now, in practice, any such apparatus is bound to lose energy by heat transfer to the surroundings; but we can imagine that this is reduced to a very low rate. The idealized apparatus is then a model of the state of affairs inside a cylinder when a mixture of petrol vapour and air explodes in it and the piston moves outwards in the cylinder. That state of affairs lasts only a fraction of a second. Using the RESPONSE ARRAY, compose a description of this situation. Use the model as a guide but not as a substitute.

1
U = 0		 2
conversion of work into internal energy by compression		 3
transition of energy from potential state to thermal state		 4
conversion of internal energy into work by expansion		 5
Q = 0
6
transfer of energy through adiabatic enclosure		 7
specific heat		 8
heat transfer		 9
W = 0		 10
enclosure permitting transfer of energy by heat and by work
11
change of phase of the kind: liquid vapour		 12
chemical energy		 13
U 0		 14
T 0		 15
H 0
16
thermal equilibrium		 17
uncertainty of change in U		 18
V = 0		 19
P = 0 		20
T = 0