In two or more complete sentences, compare single displacement reactions and double displacement reactions.

explanation:

single displacement reactionsare the reactions in which one element displaces another element from its chemical reaction. these reactions are judged with the of reactivity series.

the metal which is present above in the reactivity series will displace the metal which lies below in the reactivity series. the equation follows:

a is more reactive than b.

double displacement reactions are the reactions in which exchange of ions takes places in a chemical reaction. the equation follows:

In single displacement reactions, there is an exchange of partners between the reactants and the products only once. in double displacement reactions, an exchange of partners between the reactants and products happens twice.

Because a model would make the investigation easier to understand

Answer : option c) heat is released during the process.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.