 Let's wrap things up with a couple of review questions. In thermodynamics, a fixed quantity of mass selected for the purpose of study is called a closed system, is the best of the available answers, because a fixed quantity of mass would have no mass entering nor leaving, it would be a closed system. A specific property is also an intensive property. Remember that a specific property is an extensive property divided by mass. That makes it intensive. In order for a system to be in thermal equilibrium, which of the following properties must be the same throughout the system? That's right, temperature. Next, a cycle consists of a sequence of processes, which eventually get back to where they started. Even though the continual repetition is often implied in our analysis of a cycle, that's not the thing that actually makes up a cycle. How many independent properties are required to completely specify the state of a simple compressible system? Two. It takes two. A one-half cubic meter container is filled with a fluid whose specific volume is 0.001 cubic meters per kilogram. At standard gravitational acceleration, the contents of this container weigh, well remember, specific volume is volume expressed per unit mass. Therefore mass could be described as volume divided by specific volume. Force of weight is going to be mass times gravity. That means that what we're describing here is a volume multiplied by gravity divided by a specific volume. The volume is 0.5 cubic meters, dividing by 0.001 cubic meters is going, excuse me, cubic meters per kilogram is going to yield a quantity in kilograms. And since it's 5 divided by 0.001, that's equivalent to 0.5 times 1000, which would be about 500. Since we have standard gravitational acceleration, that means 9.81 meters per second squared, 500 kilograms multiplied by 9.81 meters per second squared is going to be closest to 4900 Newtons. And with that we conclude chapter one. Next up will be the discussion of energy and the first law of thermodynamics. We will start to get into quantifying energy and using the first law, the conservation of energy, to predict what's going to happen in a process. It will be exciting.