Suppose you need to heat food. What wave type from the electromagnetic spectrum could you use?

Microwave radiation

Explanation:

This radiation is the one used in microwaves.

Infrared

Explanation:

Infrared light is used by electrical heaters, cookers for cooking food, and by infrared cameras which detect people in the dark. Infrared light has frequencies which are absorbed by some chemical bonds. The internal energy of the bonds increases when they absorb infrared light, which causes heating.

the ratio of the conjugate base to the acid required to attain the desired ph.

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.