Chapter 12 Section 1

Which type of reaction is a combustion reaction?

All combustion reactions are exothermic.

What are exothermic reactions?

Exothermic reactions are reactions that release heat.

What occurs in chemical reactions?

In a chemical reaction, existing bonds are broken, atoms are rearranged, and new bonds are formed. Since bond breaking requires energy and bond formation releases energy, almost all chemical reactions absorb or release energy. This results in energy flow or heat.

What happens to energy in exothermic reactions?

In exothermic reactions, the energy released as new bonds are formed in the products is greater than the energy required to break apart the old bonds in the reactants.

What happens to energy in an endothermic reaction?

The energy released in endothermic reactions are always less than the energy required.

On which side of a chemical equation does the energy term appear in an exothermic reaction?

The products side (right)

On which side of a chemical equation does the energy term appear in an endothermic reaction?

The reactants side (left)

What is thermochemistry?

Thermochemistry is the changes in heat in chemical reactions.

GIve an example of an endothermic reaction equation.

C(s) + H2O (g) +113 kJ = CO (g) +H2 (g)

Give an example of an exothermic reaction equation.

C3H8(s) + 5O2 (g) = 3CO2(g)+ 4H2O(g) +2043kJ

What are endothermic reactions?

Endothermic reactions are reactions that absorb heat.

What is heat?

Heat is the energy that is transferred from one object to another due to a difference in temperature.