Review: Exothermic vs endothermic

What is an exothermic reaction?

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

What is an endothermic reaction?

An endothermic reaction is a process that absorbs energy from its surroundings, resulting in a decrease in temperature.

True or false: Combustion is endothermic.

False, because combustion is an exothermic reaction, releasing heat and light.

Difference between exothermic and endothermic

Exothermic: releases heat; Endothermic: absorbs heat.

Fill in the blank: Photosynthesis is an __________ process.

Endothermic: it absorbs sunlight to convert carbon dioxide and water into glucose.

What happens to temperature in an exothermic reaction?

The temperature rises as heat is released into the surroundings.

Is melting ice exothermic or endothermic?

Endothermic: ice absorbs heat from the environment to melt.

What is an example of an exothermic reaction?

Combustion of fuels, such as burning wood or gasoline.

True or false: Ice melting is an exothermic process.

False, because melting ice absorbs heat, making it endothermic.

Which process is exothermic?

Respiration: it converts glucose and oxygen into carbon dioxide and water, releasing energy.

Energy diagram of exothermic reaction

The products have lower energy than the reactants, indicating energy release.

What occurs during an endothermic reaction?

Energy is absorbed, often resulting in a decrease in temperature of the surroundings.

Example of endothermic reactions

Baking soda reacting with vinegar absorbs heat and cools the mixture.

True or false: All chemical reactions are either exothermic or endothermic.

True, because every chemical reaction involves energy transfer.

Difference in energy flow

Exothermic: energy flows out; Endothermic: energy flows in.

What is an important factor in determining reaction type?

The enthalpy change ($\displaystyle riangle H$) indicates if a reaction is exothermic or endothermic.

Fill in the blank: Dissolving ammonium nitrate in water is __________.

Endothermic: it absorbs heat and feels cold to the touch.