Endothermic and Exothermic Reactions

Jana, a chemistry tutor, explains the concepts of endothermic and exothermic reactions, focusing on enthalpy changes. She describes how energy profiles illustrate these reactions, with endothermic reactions absorbing energy (positive Delta H) and exothermic reactions releasing energy (negative Delta H). The tutorial aims to help students understand these concepts for their chemistry studies.

What is the basis of endothermic and exothermic reactions?

• Pressure change

• Enthalpy change

• Volume change

• Temperature change

In an endothermic reaction energy profile, what does the top line represent?

• Volume

• Time

• Pressure

• Enthalpy

For an endothermic reaction, how does the enthalpy of reactants compare to that of products?

• Reactants have more enthalpy

• Reactants have less enthalpy

• Reactants and products have equal enthalpy

• Enthalpy is not involved

What is the sign of Delta H in an endothermic reaction?

• Negative

• Zero

• Positive

• Undefined

In an exothermic reaction energy profile, how does the enthalpy of reactants compare to that of products?

• Reactants have less enthalpy

• Enthalpy is not involved

• Reactants have more enthalpy

• Reactants and products have equal enthalpy

What is the sign of Delta H in an exothermic reaction?

• Negative

• Undefined

• Zero

• Positive

Which type of reaction absorbs energy from the surroundings?

• Neither

• Exothermic

• Endothermic

• Both

Which type of reaction releases energy to the surroundings?

• Neither

• Exothermic

• Endothermic

• Both

In which reaction do the products have more energy than the reactants?

• Exothermic

• Endothermic

• Both

• Neither

In which reaction do the reactants have more energy than the products?

• Exothermic

• Endothermic

• Both

• Neither