Q17 P - Chemistry: Molecular Nature Of Matter And Change

Question

In the following relationships, which quantities are variables and which are fixed: (a) Charles’s law; (b) Avogadro’s law; (c) Amontons’s law?

Step-by-Step Solution

Answer

1. In Charles’ law, volume and temperature are variables while concentration and pressure are fixed.
2. In Avogadro’s law, volume and number of moles of gas are variable while pressure and temperature are fixed.
3. In Amonton’s law, pressure and temperature of a gas are variable while volume and  number of moles of gas are fixed.

Step 1: Charles’ law

According to Charles’ law, at constant pressure and fixed concentration, the 

volume of a gas is directly proportional to the temperature.

$$\begin{gathered} V\infty T \\ \frac{V}{T}=cons\tan t(P,n fixed) \end{gathered}$$

Where, V = volume, T = temperature, P = pressure, n = number of moles

 

Thus, in Charles’s law, volume and temperature are variables while moles and pressure are fixed.

Step 2: Avogadro’s law

According to Avogadro’s law, at constant temperature and pressure, the number of moles of gas is directly proportional to the volume.

$$\begin{gathered} V \alpha T \\ \frac{V}{n}=cons\tan t(P,T fixed) \end{gathered}$$

Thus, in Avogadro’s law, volume and moles of gas are variable while pressure and temperature are fixed.

Step 3: Amonton’s law

According to Avogadro’s law, at constant volume and moles of the gas, the pressure is directly proportional to the temperature.

$$\begin{gathered} P \alpha T \\ \frac{P}{T}=cons\tan t(V,n fixed) \end{gathered}$$

Thus, in Amonton’s law, pressure and temperature of the gas are variables while volume and number of moles of the gas are fixed.