Thermochemistry

Front

What is thermochemistry?

Back

Thermochemistry is the study of the heat energy associated with chemical reactions and changes of state.

Front

What does the enthalpy change of formation represent?

Back

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

Front

Write the equation for the enthalpy change of formation of magnesium chloride (MgCl2).

Back

Mg(s) + Cl2(g) → MgCl2(s)

Front

What is an exothermic reaction?

Back

An exothermic reaction is a chemical reaction that releases heat to its surroundings.

Front

What is an endothermic reaction?

Back

An endothermic reaction is a chemical reaction that absorbs heat from its surroundings.

Front

What is the First Law of Thermodynamics?

Back

The First Law of Thermodynamics states that energy cannot be created or destroyed, only transformed from one form to another.

Front

In an endothermic reaction, what can be said about the bonds in the products compared to the reactants?

Back

In an endothermic reaction, the products have weaker bonds than the reactants.

Front

What happens to the temperature of a system during an exothermic reaction?

Back

The temperature of the system increases during an exothermic reaction as heat is released.

Front

What occurs when two solids at different temperatures are placed in contact?

Back

Heat energy flows from the hotter solid to the cooler solid until thermal equilibrium is reached.

Front

What is thermal equilibrium?

Back

Thermal equilibrium is the state in which two objects in contact with each other reach the same temperature and no heat flows between them.