A 2000 cm3 container holds 0.10 mol of helium gas at 300°C. How much work must be done to compress the gas to 1000 cm3 at (a) constant pressure and (b) constant temperature?
a. The value of work done at constant pressure is 240J
b. The value of work done at constant volume is 330J
The work done has represented as energy that is transferred between system and environment.
The value of the changeable volume is
the equation of real gas is
So the work done is
Now the temperature in Kelvin is (= 573K
a. The value of work done at constant pressure
b. The value of work done at constant pressure
When air is inhaled, it quickly becomes saturated with water vapor as it passes through the moist airways. Consequently, an adult human exhales about 25 mg of evaporated water with each breath. Evaporation—a phase change—requires heat, and the heat energy is removed from your body. Evaporation is much like boiling, only water’s heat of vaporization at 35°C is a somewhat larger 24 * 105 J/kg because at lower temperatures more energy is required to break the molecular bonds. At 12 breaths/min, on a dry day when the inhaled air has almost no water content, what is the body’s rate of energy loss (in J/s) due to exhaled water? (For comparison, the energy loss from radiation, usually the largest loss on a cool day, is about 100 J/s.)
You come into the lab one day and find a well-insulated thermos bottle containing of boiling liquid nitrogen. The remainder of the thermos has nitrogen gas at a pressure of atm. The gas and liquid are in thermal equilibrium. While waiting for lab to start, you notice a piece of iron on the table with " " written on it. Just for fun, you drop the iron into the thermos and seal the cap tightly so that no gas can escape. After a few seconds have passed, what is the pressure inside the thermos? The density of liquid nitrogen is .
94% of StudySmarter users get better grades.Sign up for free