It should remain constant because of the law of conservation of mass and because the flask is sealed no mass will escape
Answer:
Thermal Energy
Explanation:
I'll give you an example, Rub your hands together. Then touch your face or leg to feel any temperature change. Most likely your hands are warmer.
A. proton donating is often referring to Hydrogen donating in acids. See the extra H+ in common acids: HCl, H2SO4
