After an endothermic reaction, the number of protons in a sodium ion, na+, is

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?

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What metric units would you use to measure the thickness of a key