PLEASE HELP I WILL MARK BRAINLIEST

Reaction

The amount of mass after being weighed is not in accordance with the law of conservation mass, because the amount is less.

If we total the mass before the reaction

flask + NaHCO₃ + CH₃COOH = 55 + 5 + 15 = 75 g

Total mass after weighing = 73 g

It should stay the same at 75 g if we refer to the law of mass conservation

I believe this law applies to this reaction if we do it in a closed system as stated in the law

Conservation of mass: stated :

In a closed system, the total mass of the substance before the reaction will be equal to the total mass of the reaction product.

This reaction is carried out in open conditions so that the mass can be smaller after weighing

If we look at the reaction, it will form CO₂ gas as evidenced by the presence of bubbles when mixing (mixing is one way to speed up the reaction)

So that the balance results are expected to be the same between before and after the reaction, it can be done in a closed system by closing the flask (by stopper), so that the gas that comes out (CO₂) can be trapped in the flask.

a electronegativity decreases beacuse the size of nucleus is bigger.

what is the question here. i think you messed up.