Matter - Interactions

Vocabulary 1 Element – a pure substance that cannot be separated into simpler substances by physical or chemical means Compound – a pure substance composed of two or more elements that are chemically combined

Vocabulary 1 Subscript – a number written below and to the right of a chemical symbol in a formula Superscript – a number written above and to the right of a symbol to show charge of an ion Coefficient – a number placed in front of a compound to show how many of them there are

Vocabulary 1 Chemical change – a change that occurs when one or more substances are changed entirely into new substances with different properties – not reversible Physical change – a change of state, but not composition

Basic Building Blocks: Element: pure substance made of only one kind of atom – not separable Compound: substance that is made of two or more elements that are chemically bonded – can be separated by chemical means only.

Basic Building Blocks: Heterogeneous Mixture- physical blend of two or more substances that are not uniform Homogeneous mixture – a physical blend of two or more substances that have the same composition Called a solution

Vocabulary #2 Organic compounds – compounds containing carbon (part of all living things) Inorganic compounds – all other compounds not containing carbon Chemical reaction - the process by which one or more substances change to produce one or more different substances

Vocabulary 2 Endothermic – the term used to describe a physical or chemical change in which energy is absorbed. Exothermic – the term used to describe a physical or chemical change in which energy is given off. Precipitate – a solid formed in a solution as a result of a chemical reaction

Law of Conservation of Mass Mass is neither destroyed nor created during ordinary chemical reactions or physical changes pure chemical compound has a fixed proportion of elements

Matter Has both physical and chemical properties Physical property: characteristic that can be observed or measured without changing the identity melting point boiling point color of an apple phase change: IceWatervapor(steam)

What are Physical Properties and Changes? Physical properties are used to observe and describe matter.

What are Physical Properties and Changes? Physical properties include: appearance, texture, color, odor, melting point, boiling point, density, specific heat, and many others.

Ex: grinding, cutting, boiling Physical change Changes in a substance that does not involve a change in the identity of the substance Ex: grinding, cutting, boiling

EX: combustion - charcoal (carbon) burns in air CO2 Iron rust Chemical Property Substances ability to undergo changes that transform it into a different substance EX: combustion - charcoal (carbon) burns in air CO2 Iron rust

One or more substances are converted into a different substance Chemical change One or more substances are converted into a different substance When chemical or physical changes occur, Energy (E) is always involved.

What is a Chemical Change? alters the composition of the original matter. Different elements or compounds are present at the end of the chemical change. The atoms in compounds are rearranged to make new and different compounds.

5 Signs of a Chemical Change Color Changes

5 Signs of a Chemical Change Odor Changes When you smell an odd order in foods such as chicken, pork of mayonnaise, you know that the food has undergone a chemical change.

5 Signs of a Chemical Change Temperature Changes Another sign of a chemical change is the release or gain of energy by an object. Energy can be released during a reaction, resulting in heat or light. Energy can be absorbed during chemical changes creating a decrease in temperature, like with this cold pack.

5 Signs of a Chemical Change Production of Gases The formation of a gas is  a clue to chemical changes.  The bubbles of gas that you observed form when an antacid is dropped into water is an example of change.

5 Signs of a Chemical Change Production of Solid Another clue that a chemical change has occurred is the formation of a solid.  A solid that separates out of solution during a chemical change is called a precipitate. This curdled milk has precipitates inside.