Chapter 2 Introduction to Matter Section 1 Describing Matter

Properties of Matter Matter is anything that has mass and takes up space (has volume). Chemistry is the study of the properties of matter and how matter changes. A substance is a single kind of matter that has specific make-up, specific properties, specific characteristics, and is pure. ex. Table sugar and table salt (C12H22O11 and NaCl)

4. Every form of matter has 2 types of properties – physical and chemical. 5. A Physical Property is a characteristic of a pure substance that can be observed without changing the substance into another substance. ex. Melting temperature, state, dissolving in water, temperature, etc…

6. A Chemical Property is a characteristic of a pure substance that describes its ability to change into different substances with new properties. ex flammability, reactivity or non reactivity,

Elements a. Listed on the periodic table. 1. An Element is a pure substance that cannot be broken down into any other substances by physical or chemical means. a. Listed on the periodic table. b. can be identified by its physical and chemical properties. 2. An atom is a basic particle from which all elements are made. Different elements have different properties because their atoms are different. 3. A chemical bond is the force of attraction between two atoms.

4. A molecule is a group of two or more atoms held together by chemical bonds. ex water molecules consist of 1 oxygen atom and 2 hydrogen atoms.

Compounds A compound is a pure substance made of two or more elements chemically combined in a set ratio. A chemical formula shows the ratio of atoms in a compound. CO2 Tells the number of atoms to the left If there is no #, then it is assumed to be 1

3. When elements chemically combine, they form compounds with properties different from those of the uncombined elements. C12H22O11 is sugar! H is hydrogen (clear gas) O is oxygen (clear gas) C is carbon

Mixtures A mixture is 2 or more substances (elements, compounds or both) that are together but not chemically combined. Each substance keeps its individual properties. Not in a set ratio. How much sugar do you put in your tea? (or coffee or cereal)

Heterogeneous Mixtures 1. Heterogeneous mixtures are those where you can see the individual parts. Ex. Salads, Italian dressing, tacos, etc.

Homogeneous Mixture 1. Homogeneous Mixtures are mixed so evenly that you cannot see the individual parts. 2. A solution is a homogeneous mixture where one substance is dissolved into the other.