Science endothermic

Exothermic Reaction

A chemical reaction that releases thermal energy into the surroundings, causing the temperature to rise.

Endothermic Reaction

A chemical reaction that absorbs thermal energy from the surroundings, causing the temperature to fall.

Reactants

The starting substances in a chemical reaction, found on the left side of the arrow.

Products

The new substances formed in a chemical reaction, found on the right side of the arrow.

Sherbet Word Equation

sodium hydrogencarbonate + citric acid -> sodium citrate + water + carbon dioxide.

Sherbet Energy Change

Endothermic (it absorbs heat from your mouth to react).

Potassium Chloride Dissolving Equation

potassium chloride (solid) + water -> potassium chloride (solution).

Potassium Chloride Process

Endothermic physical process (the beaker feels cold as the salt dissolves).

Surroundings

Everything outside the chemical reaction, such as the air, the beaker, or your tongue.

Chemical Change

A process where new substances are formed and atoms are rearranged.

Physical Process

A change where no new substances are made, such as dissolving or changing state.

Solvent

The liquid in which a substance dissolves (e.g., water or saliva).

Solute

The solid substance that is dissolved (e.g., potassium chloride or citric acid).

Solution

The mixture formed when a solute has dissolved in a solvent.

Carbon Dioxide

The product gas that causes the “fizzy” feeling in sherbet.

Sodium Hydrogencarbonate

A reactant in sherbet that reacts with acid to produce gas.

Citric Acid

A reactant in sherbet that provides the sour taste and triggers the reaction.

Temperature Increase

The main observation of an exothermic reaction.

Temperature Decrease

The main observation of an endothermic reaction.

Thermal Energy

The type of energy (heat) transferred during these reactions.

The Arrow (->)

In a word equation, it means “reacts to form.”

Conservation of Energy

The principle that energy is not created or destroyed, only transferred.

Bonds Breaking

An endothermic step because energy is required to pull atoms apart.

Bonds Forming

An exothermic step because energy is released when atoms join together.

Reaction Profile

A diagram showing the energy levels of reactants vs. products.

Exothermic Profile

A graph where the products have less energy than the reactants.

Endothermic Profile

A graph where the products have more energy than the reactants.

Neutralization

The type of reaction between an acid and a carbonate (like the sherbet reaction).

Stirring

A manual action used to help a solute dissolve faster in a solvent.

Cooling Sensation

The feeling caused when a reaction takes heat from its surroundings (like your mouth).