Receptors in your stomach that determine when food enters because the ph changes would be classified as

Chemoreceptors

Explanation: Chemoreceptors is a sense organ, or one of its cells (such as those for the sense of taste or smell), that can respond to a chemical stimulus; a chemosensor. Chemosensors converts chemical signals and generates biological signals. In this case, a taste receptor is used which is the tongue.

The two main classes of receptors are direct chemoreceptor(taste) and distance chemoreceptor(olfactory).

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.