The correct answer is B. Chewing in the mouth breaks food into small pieces.
Explanation:
In physical changes, substances do not change their chemical composition or properties but only physical features such as this. This occurs during the chewing because the action of chewing only makes food to be broken down in smaller pieces but does not change its identity, composition, or properties. This does not occur once the food is in contact with saliva, the acid in the stomach, etc. because in these cases, the food reacts with other substances and a chemical reaction occurs, which changes food's identity and composition.
The correct answer would be the first option. The arrows 1, 2 and 3 represent the phase transitions where heat energy is gained. As heat energy is gained the kinetic energy of the molecules in a substance is increased which would cause them to change phases from solid to liquid and to gas.
The expression for the Ka for the given acid is:
Ka = [H2P2O7^2-] [H3O+] /[H3P2O7^2-]
<span>Ka is the acid dissociation constant or the acidity constant. It is a measure of the acid strength when in solution. It is an equilibrium constant for the dissociation of the acid.</span>
