IB Physics Longitudinal Waves

A tutorial sheet of  longitudinal wave questions is given below.

1. A longitudinal progressive wave moving from left to right has a frequency f and wavelength λ. Two particles, P and Q, have equilibrium positions one-half a wavelength apart. At a certain instant P is at rest and is displaced to the left of its equilibrium position.(a) What is the amplitude of oscillation of P? (b) What is the displacement of Q from its equilibrium position?
2. Do we have nodes in longitudinal progressive waves?
3. In a longitudinal standing wave at which points in the pattern is the pressure greatest?
4. In a longitudinal standing wave at which points in the pattern is the density greatest?
5. In a longitudinal standing wave do all particles have the same frequency of vibration?
6. In a longitudinal standing wave are all of the particles vibrating in phase?
7. In a longitudinal standing wave the pressure mimima (rarefactions) are positions where the particles have zero displacement from their equilibrium position. Why is this?
8. Are the pressure maxima (compressions) at a position of zero particle displacement?
9. A closed pipe of length 1.5m is sounding its third harmonic. If the maximum possible displacement of a particle in the pipe from its equilibrium position is a what is the maximum displacement of a particle 0.25 m from the closed end of the tube? The speed of sound is 343 m/s and neglect the end correction.
10. Where would you hear a louder sound, at the anti-node or at the node of displacement of a standing wave?