Question

True statements:1) deltaH for endothermic reaction is positive3) when the energy is transferred as heat from system to surroundings, deltaH is negative.6) A combustion reaction is exothermic .False statements:2) deltaH for exothermic reaction is positive. actually it is negative4) when the energy is transferred as heat from surroundings to system, deltaH is negative. actually it is positive5) the evaporation of water is an exothermic process. actually it is an endothermic process.

Answer 1

 Answer:

Delta H for endothermic reaction is positive-True. This is because an endothermic reaction absorbs heat energy, therefore more energy is retained inside the product of the reaction system than the reactants, as the value of deltaH is greater than Zero.

Delta H for an exothermic reaction is positive. This is false. Because in an exothermic reaction  heat is liberated to the  surrounding environment. therefore the value of thus the outer environment contains more energy than the internal environments, thus the enthalpy of the reactants is greater than that of the products.

when the energy is transferred as heat from system to surroundings, deltaH is negative. True . This is true because the surrounding environment gain heat energy, (positive)while  the system loses it,(negative) therefore delta H is negative.

when the energy is transferred as heat from surroundings to system, deltaH is negative.  False. This is  positive, because now the environments loses heat, (negative) while the systems gains heat,( positive) therefore delta H of the system is positive. endothermic

the evaporation of water is an exothermic process-False, This is an endothermic reaction in which water molecules need to gain heat energy from the surrounding environments to increase the average kinetic energy  of collusion to escape the intermolecular forces to escape as steam.

Combustion reaction is exothermic. True., because heat energy is transferred to the surrounding from the internal system. The energy needed for the formation  of  new bonds in the products is higher than the energy for breaking of original bonds in the reactants. Thus more heat is liberated.

Explanation: