4. Escribe una apreciación crítica acerca de la conservación de alimentos mediante el uso del ÁCIDO SULFHÍDRICO

hydrogen sulfide is used for the preservation of food materials.

Explanation:

Hydrogen sulfide is a chemical used for the preservation of food materials. It preserves food by preventing the growth of microbes in the food materials. Due to this chemical, the flavor, smell and color of food materials should be maintained for a very long time. Hydrogen sulfide also delays food maturation and minimum chances of food spoilage will occurs in the presence of this chemical.

1. they vary with a higher number because boiling is way hotter than melting

i just calculated it all out, and not including weekends, and all the different days off. as of this school year (2018-2019) students are spending 2198 hours in school this year