Define an exothermic reaction and an endothermic reaction.

When solid sodium hydroxide is dissolved in water, the beaker gets warm. Is this process exothermic or endothermic?

Draw a simple, labelled energy level diagram for an exothermic reaction, showing the relative energy of reactants and products.

Draw a simple, labelled energy level diagram for an endothermic reaction.

Cellular respiration is an exothermic process. What happens to the energy that is released?

Photosynthesis is a key example of an endothermic process. What is the source of energy that is absorbed?

What is the name given to the amount of heat absorbed or released during a chemical reaction?

Write the general equation for calculating the heat change in a solution: Q = ? and define each term.

If the temperature of a reaction mixture increases, is heat being absorbed or released by the reaction?

When 50 cm³ of an acid is mixed with 50 cm³ of a base, the temperature rises by 10 °C. Calculate the heat energy (Q) released in joules. (Assume the density of the solution is 1 g/cm³ and its specific heat capacity is 4200 J kg⁻¹ °C⁻¹).

Why is a polystyrene cup often used in experiments to measure heat changes (calorimetry)?

Why is it important to state the physical states (s, l, g, aq) of reactants and products when quoting the heat of reaction?

Name an endothermic process that occurs in industry.

Give a common, everyday example of an exothermic reaction.

In an endothermic reaction, do the products have more or less energy than the reactants?