Physical and Chemical Changes

VOCABULARY flashcards covering the concepts of physical and chemical changes, indicators of chemical reactions, and specific examples provided in the lecture notes.

Physical Change

A change in which no new chemical species forms and the identity of the matter does not change, such as changing state between solid, liquid, and gas phases.

Chemical Change

A change where atoms rearrange themselves to form new chemical bonds, resulting in a new compound known as a product.

Chemical Reaction

A process in which one or more substances (reactants) are converted to one or more different substances (products) by rearranging constituent atoms.

Reactants

The starting substances in a chemical reaction that are converted into different substances.

Products

The new substances that result from a chemical reaction after atoms have rearranged.

Substances

In chemical reactions, these are classified as either chemical elements or compounds.

Change in Color

A permanent shift in a substance's appearance that serves as an indicator of a chemical change.

Exothermic

A type of temperature change where the system becomes hotter.

Endothermic

A type of temperature change where the system becomes colder.

Precipitate

A solid that appears after mixing two liquids, indicating a chemical change has occurred.

Production of Light or Odor

An indicator of chemical change involving the emission of energy as light or the release of new scent molecules.

Evolution of Gas

The appearance of bubbles or fizzing, which indicates a chemical change.

Baking Bread

An example of chemical change where gas evolution from yeast producing $CO_2$ creates holes and heat causes a color change on the crust.

Battery Power

An example of chemical change where reactions inside a battery produce a temperature change and release electrical energy.

Digestion

A process where enzymes break down food using chemical reactions, often producing gas and changing the chemical structure of nutrients.