Physics 6.2.3 Molecular Kinetic Theory Model

7 flashcards · Physics · by TheoTyson

1. What assumptions are made in deriving the equation for pressure of an ideal gas?

   The collisions are perfectly elastic and random. The duration of collisions is negligible. The molecules move in straight lines. The particles follow Newton's Laws.

2. What are the steps in deriving the equation for pressure of an ideal gas?

   Change in momentum = 2mu2mu2mu . Time between collisions = 2lu\frac{2l}{u}u2l​ . Force = momentum / time = 2mu2lu\frac{2mu}{\frac{2l}{u}}u2l​2mu​ = mu2l\frac{mu^2}{l}lmu2​ . Pressure = force / area = mu2ll2\frac{\frac{mu^2}{l}}{l^2}l2lmu2​​ = mu2V\frac{mu^2}{V}Vmu2​ . Multiply by number of particles = Nmu2ˉV\frac{Nm\bar{u^2}}{V}VNmu2ˉ​ . Speed in each direction c2ˉ=u2ˉ+v2ˉ+w2ˉ\bar{c^2} = \bar{u^2} + \bar{v^2} + \bar{w^2}c2ˉ=u2ˉ+v2ˉ+w2ˉ . Average speed u2ˉ=v2ˉ=w2ˉ\bar{u^2} = \bar{v^2} = \bar{w^2…

3. What is the root mean squared?

   r.m.s\text{r.m.s}r.m.s = mean square speed\sqrt{\text{mean square speed}}mean square speed ​ = c2ˉ\sqrt{\bar{c^2}}c2ˉ ​ = crmsc_{\text{rms}}crms​

4. What are empirical laws?

   Laws based on observations and evidence such as the gas laws.

5. What are theoretical models?

   Models based on assumptions and derivations such as kinetic theory.

6. What is Brownian motion?

   The random motion of larger particles in a fluid colliding with surrounding particles.

7. What is the internal energy of an ideal gas dependent on?

   The kinetic energy of the particles.