For what experimental circumstance would one want to use a pathlength other than 1.000 cm for an absorbance experiment

What type of reaction is zn + cucl2 → cu + zncl2?

Astudent carefully transfers 30 g of water and 30 g of alcohol in a glass tube, forming two layers and filling the tube completely. after sealing the tube, the student mixes the solutions, and notices a bubble that forms in the tube. what is the mass of the contents in the glass tube after mixing?

In pqr m< p=60 m< q= 30 and m