Ideal and Real Gases
Ideal gases obey conditions of the general gas laws under all states of pressure and temperature. Ideal gases are also named perfect gases. The attributes of ideal gases are as follows,
Gas Laws
Gas laws describe the ways in which volume, temperature, pressure, and other conditions correlate when matter is in a gaseous state. The very first observations about the physical properties of gases was made by Robert Boyle in 1662. Later discoveries were made by Charles, Gay-Lussac, Avogadro, and others. Eventually, these observations were combined to produce the ideal gas law.
Gaseous State
It is well known that matter exists in different forms in our surroundings. There are five known states of matter, such as solids, gases, liquids, plasma and Bose-Einstein condensate. The last two are known newly in the recent days. Thus, the detailed forms of matter studied are solids, gases and liquids. The best example of a substance that is present in different states is water. It is solid ice, gaseous vapor or steam and liquid water depending on the temperature and pressure conditions. This is due to the difference in the intermolecular forces and distances. The occurrence of three different phases is due to the difference in the two major forces, the force which tends to tightly hold molecules i.e., forces of attraction and the disruptive forces obtained from the thermal energy of molecules.
![**Question:**
An unknown diatomic gas has a density of 3.164 g/L at STP. What is the identity of the gas?
[Answer Box: _______]
**Explanation:**
To determine the identity of the diatomic gas, we can use the Ideal Gas Law equation and the concept of molar volume at standard temperature and pressure (STP).
At STP (0°C and 1 atm), the molar volume of an ideal gas is 22.414 L/mol.
1. Calculate the molar mass (M) of the gas using the density (d) formula for gases:
\[ \text{Molar Mass (M)} = \text{density (d)} \times \text{Molar Volume (V)} \]
\[ M = (3.164 \, \text{g/L}) \times (22.414 \, \text{L/mol}) \]
\[ M = 70.909 \, \text{g/mol} \]
2. Given that the gas is diatomic, the molar mass represents two atoms of the element. Thus, the atomic mass of each atom would be:
\[ \text{Atomic Mass} = \frac{\text{Molar Mass}}{2} \]
\[ \text{Atomic Mass} = \frac{70.909 \, \text{g/mol}}{2} \]
\[ \text{Atomic Mass} \approx 35.45 \, \text{g/mol} \]
3. By referring to the periodic table, an atomic mass of approximately 35.45 g/mol corresponds to the element Chlorine (Cl).
Therefore, the unknown diatomic gas is likely Chlorine gas (Cl₂).](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fedc8493a-3e6b-4673-a4c2-aec86550e951%2Ffc751da7-cf5a-4c1f-b61a-4bedd550a6f1%2F7kfbi79_processed.png&w=3840&q=75)
![**Ideal Gas Law Application: Problem Example**
An ideal gas is contained in a cylinder with a volume of 4.8 × 10² mL at a temperature of 30.0°C and a pressure of 710.0 torr. The gas is then compressed to a volume of 26 mL, and the temperature is raised to 820.0°C. What is the new pressure of the gas?
**Pressure =** [ ] torr](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fedc8493a-3e6b-4673-a4c2-aec86550e951%2Ffc751da7-cf5a-4c1f-b61a-4bedd550a6f1%2F56yk938_processed.png&w=3840&q=75)
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