Elements/Compounds

Admit Slip Which of the following is a homogeneous mixture and why? A) Water H 2 O B) Tomato soup C) A turkey sandwich D) Table salt, NaCl

Today’s Objectives: Students will be able to: Define, compare and contrast mixtures, heterogeneous mixtures, homogeneous mixtures, phases Define and compare elements, compounds, and pure substances

Agenda Homework Check (Mixtures Worksheet/Lab) Notes Elements/Compound Questions Exit Slip

Notes Elements are pure substances that are the simplest form of matter. They are made up of all the same type of atom. They can be found on the Periodic Table of Elements.

Notes Compounds are also pure substances that are a fixed proportion of two or more elements that are bound chemically. Compounds differ from mixtures in they are bound chemically, not just physically.

Notes Compounds can be broken down into elements or simpler compounds using a chemical change (chemical reaction). When a chemical change occurs, you will have matter with a different composition.

Notes

Chemical symbols are one or two letters used to represent elements. The first letter is always capitalized. A chemical formula contains more than one symbol and may contain subscripts (numbers written low). They indicate the proportion of atoms of each element in a compound. Example: CH 4

Question A clear liquid in an open container is allowed to evaporate. After three days, a solid is left in the container. Was the clear liquid an element, a compound, or a mixture? How do you know?

Exit Slip/Homework Compare and Contrast Paragraph Compare and contrast elements and compounds. Compare them by saying how they are alike. Contrast them by describing how they are different. HW: Skim Ch. 9 for the answers to your HW p. 266 (#1-5, #17)