List four elements used in dfds, draw the symbols, and explain how they are used.

a. Processes: - Is a series of steps that manipulate data b. Data flows: - Describes the data and the information elements passing between external entities, processes and data stores c. Data stores: - A place to keep data for later use d. External entities:- The original source of data or the receiver of information

a patient chooses to not take a beneficial medical treatment.

explanation:

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.