Elements, Compounds & Mixtures

What is an ELEMENT? A substance composed of a single kind of atom. Cannot be broken down into another substance by chemical or physical means.

Elements

What is a COMPOUND? A substance in which two or more different elements are CHEMICALLY bonded together.

Hydrogen (H) + Oxygen (O) Examples of Compounds Sodium (Na) + Chlorine (Cl) NaCl Hydrogen (H) + Oxygen (O) H2O Carbon (C) + Oxygen (O) CO2

What is a MIXTURE? Two or more substances that are mixed together but are NOT chemically bonded.

Mixtures Physical properties can change, but no new substance is formed No new chemical bonds are formed Can be easily separated into distinct parts

Examples of Mixtures Properties of Mixtures: chicken noodle soup salad pizza – yes, that would be Yoda… Properties of Mixtures: Each substance ikeeps its identity can physically separate them Examples: jar of colored jelly beans trail mix

Further Classification of mixtures: Solutions (homogenous) Suspensions (heterogenous)

Solutions A solution -mixture that appears to be a single substance; actually composed of 2 or more substances that are distributed evenly SOLUTIONS ARE HOMOGENEOUS sugar & Kool-Aid powder are dissolved in water carbon dioxide is dissolved in water salt is dissolved in water

Mixtures may be homogeneous or heterogeneous 1. Homogeneous mixtures (prefix “homo” – same) same appearance same properties throughout the mixture 2. Heterogeneous mixtures - visibly different substances (prefix “hetero” indicates difference)

Suspensions A suspension - mixture in which particles of a material are dispersed throughout a liquid or gas, but are large enough that they settle out. SUSPENSIONS ARE HETEROGENEOUS That water is disgusting! muddy water Italian dressing

Element

Mixtures combination of 2 or more substances not chemically combined.

Compounds A compound is a pure substance composed of 2 or more elements that are chemically combined.