If you could build a new device that would help the world (or just you personally) what would you design? Explain what you would build, how it would work, and how it would be useful to society

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?

Acompound has a molecular weight of 12.124 atomic mass units and the empirical formula c3h40. what is the molecular formula of the compound?

In in , is to a 28.4-g (1-oz)−23.0 °c to −1.0 °c?