What type of sediments stick togetther

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?

Avariable that is not being directly tested during an experiment should be changed varied experimented controlled

What does a numerical subscript following an element in a chemical formula mean?