How is enthalpy used to predict whether a reaction is endothermic or exothermic? a. when the enthalpy of the reactants is higher than the enthalpy of the products, the reaction is endothermic. b. when the enthalpy of the products is higher than the enthalpy of the reactants, the reaction is exothermic. c. when the enthalpy change of the reaction is positive, the reaction is exothermic. d. when the enthalpy change of the reaction is positive, the reaction is endothermic.

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance

mark him as !

a boiling water reactor does not boil the water. a pressurized water reactor boils the water faster. a pressurized water reactor is heated directly by the core. a pressurized water reactor does not use fission.

the answers would be

the first one and the second one