AP Chemistry Unit 6 Thermodynamics

Front

What is the definition of an exothermic reaction?

Back

An exothermic reaction is a chemical reaction that releases energy in the form of heat to its surroundings.

Front

What is the definition of an endothermic reaction?

Back

An endothermic reaction is a chemical reaction that absorbs energy from its surroundings, usually in the form of heat.

Front

What does a negative delta H (ΔH) indicate about a reaction?

Back

A negative delta H indicates that the reaction is exothermic, meaning it releases heat.

Front

What is activation energy?

Back

Activation energy is the minimum energy required for a chemical reaction to occur.

Front

How can you determine if a reaction is exothermic or endothermic from a chemical equation?

Back

If the products have lower energy than the reactants, the reaction is exothermic. If the products have higher energy, it is endothermic.

Front

What is the standard enthalpy change of formation?

Back

The standard enthalpy change of formation is the change in enthalpy when one mole of a compound is formed from its elements in their standard states.

Front

What is the formula for calculating the standard enthalpy change of formation of methane (CH4)?

Back

The standard enthalpy change of formation of methane can be calculated using the equation: ΔH_f = ΔH_combustion + (2 × ΔH_f of H2) + ΔH_f of C.

Front

What does it mean if a reaction has a positive delta H?

Back

A positive delta H indicates that the reaction is endothermic, meaning it absorbs heat from the surroundings.

Front

What is the relationship between temperature and exothermic reactions?

Back

Exothermic reactions typically result in an increase in temperature of the surroundings.

Front

What is the significance of the enthalpy of combustion?

Back

The enthalpy of combustion is the heat released when one mole of a substance is completely burned in oxygen, important for understanding energy content.