The first part of the calculation is the same as in a previous example:. Now we can use the molar volume, Alternatively, we could have applied the molar volume as a third conversion factor in the original stoichiometry calculation.
What volume of HCl is generated if 3. The ideal gas law can also be used to determine the densities of gases. Recall that density is defined as the mass of a substance divided by its volume:. Assume that you have exactly 1 mol of a gas. If you know the identity of the gas, you can determine the molar mass of the substance. Using the ideal gas law, you can also determine the volume of that mole of gas, using whatever the temperature and pressure conditions are.
Then you can calculate the density of the gas by using. If we assume exactly 1 mol of N 2 , then we know its mass: Using the ideal gas law, we can calculate the volume:. Knowing the molar mass and the molar volume, we can determine the density of N 2 under these conditions:.
What is the density of CO 2 at a pressure of 0. These are the approximate atmospheric conditions on Mars. Breathing more properly called respiration is the process by which we draw air into our lungs so that our bodies can take up oxygen from the air. Let us apply the gas laws to breathing. Start by considering pressure.
We draw air into our lungs because the diaphragm, a muscle underneath the lungs, moves down to reduce pressure in the lungs, causing external air to rush in to fill the lower-pressure volume. We expel air by the diaphragm pushing against the lungs, increasing pressure inside the lungs and forcing the high-pressure air out. What are the pressure changes involved? A quarter of an atmosphere? A tenth of an atmosphere? Actually, under normal conditions, a pressure difference of only 1 or 2 torr makes us breathe in and out.
Breathing involves pressure differences between the inside of the lungs and the air outside. The pressure differences are only a few torr. A normal breath is about 0. With normal pressure being 1. The ideal gas law gives us an answer:. This ends up being about 0. What is the ideal gas law? What is the significance of R? Why does R have different numerical values see Table 6. A sample of gas has a volume of 3. How many moles of gas are present?
What pressure does it have? A sample of 7. What is its pressure in torr? A sample of What is its volume in milliliters? A sample of Ne has a pressure of 0. If its temperature is K, what mass is present in the sample? A mercury lamp contains 0. The molar volume of a gas expresses the volume occupied by 1 mole of that respective gas under certain temperature and pressure conditions.
So, if you are given these values for temperature and pressure, the volume occupied by any number of moles of an ideal gas can be easily derived from knowing that 1 mole occupies Let's say you were given a temperature of K and a pressure of 2.
Since molar volume refers to the volume occupied by 1 mole, you'd get. This is how much volume 1 mole occupies at K and 2. It becomes clear that the volume occupied by any number of moles at these conditions can be easily determined:. As a conclusion, knowing a gas' molar volume at a certain temperature and a certain pressure can simplify the calculation of the volume occupied by any number of moles of that respective gas. Lamarsh, A. Baratta, Introduction to Nuclear Engineering, 3d ed.
Glasstone, Sesonske. Thermodynamics in Nuclear Power Plant Systems. Modern Fluid Dynamics. Springer, , ISBN June See also: Gas Laws.
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