Unit 2- Properties of Matter Chapter 1

Unit 2 Objectives 1.) Classify matter as a pure substance or a mixture. 2.) Distinguish between chemical and physical changes, as well as chemical and physical properties. 3.) Calculate the density of an object from experimental data.

Objective 1 Classify matter as a pure substance or a mixture.

What is matter? Matter: Anything that has mass and takes up space. Mass: A measure of the amount of matter an object contains.

Types of Observations About Matter Quantitative: involve measuring and the use of numbers. Ex: The temperature was 95◦ C. Qualitative: involve descriptions. Ex: Sugar is a white, crystalline solid.

Pure Substances Matter that has fixed composition and properties. Cannot be broken down by physical methods. Two types: elements compounds

Elements A substance that cannot be broken down by chemical means. Ex: iron (Fe), carbon (C), oxygen (O), nitrogen (N)

Compounds A substance made of elements that are chemically combined. Ex: water (H2O), salt (NaCl), sugar (C12H22O11) Every compound is composed of the elements it contains.

Chemical Formula Shows the type and number of atoms present in a substance. In the chemical formula, subscripts show how many atoms are in the compound. C6H10N2O2 C = 6 H= 10 N= 2 O= 2

Mixtures Matter that has compositions that are not uniform or definite. Mixtures can be separated by physical means into the substances that are mixed with in them.

Homogeneous Mixtures Homo = same The composition is the same throughout

Examples Solid  Solid: Brass (Zinc and Copper) Liquid  Liquid: Alcohol (Ethanol and Water) Gas  Gas: Air (Nitrogen and Oxygen) Solid (dissolves)  Liquid: Salt Water (Sodium Chloride and Water) Gas (dissolves)  Liquid: Carbonation (Carbon Dioxide and Water)

Heterogeneous Mixture Hetero = different The composition is different throughout.

Practice Problems Hetero or Homo Mixture Why? Tap Water :_______________ A Rock: ________________ Stainless Steel:________________ Brewed Coffee: ________________ Sand: ________________ Oatmeal: ________________ Dust Free Air: ________________ Rusty Metal: _________________

Objective 2 Distinguish between chemical and physical changes, and chemical and physical properties.

Properties of Matter Physical Properties: Can be measured without changing the substance’s chemical composition. Ex: melting point, boiling point, density, solubility, odor, hardness, color, etc. Chemical Properties: Potential reactivity of substance with other substances. Can only be measured by trying the reactions. Ex: Any particular reaction a substance undergoes.

Changes of Matter Physical Change Chemical Change

Physical Change Alters a substance without changing the substance’s chemical composition. Ex: melting, boiling, cutting, smashing, dissolving  

Chemical Change Occur when one or more substances are changed into another substance that have different chemical compositions. Ex: rusting, exploding, decomposing, corroding, spoiling  

Practice Problems Chemical or Physical Property? Chemical or Physical Change? Tarnishes in Rain: Lighting a firework: Bends easily: Boiling Pasta: Decomposes: Chewing gum: Reusable/Recyclable: Running your car: Shiny: Rolling your bike: Not Flammable: Melting a crayon: Perishable Food: Rusting a nail: Freezable Food: Opening a can of pop:

Objective 3 Calculate the density of an object from experimental data.

Density Practice Density: The ratio of the mass of an object to its volume. Ex: Water density = 1.0 g/ml Density = mass / volume

Example What is the density of an object with a mass of 4.00 g and a volume of 4.00 ml?

Density of Rectangular Object (Wood Block) Show with pictures, label all values, and show math Measure dimensions of block (cm). Measure mass of block (g). Calculate density of block.

Density of a Liquid (water) Show with pictures, label all values, and show math Mass empty graduated cylinder. Measure 50 mL of water in cylinder. Mass of water and cylinder together. Calculate mass of water. Calculate density of water.

Density of an Irregular Solid (Putty) Show with pictures, label all values, and show math Measure mass of object. Use partially full g. cylinder. Record volume. Place object in g. cylinder. Record new volume. Calculate volume of object. Calculate density of object.

Rectangular Solid Example (In Your Notebook) block

Odd Shaped Solid Example (In Your Notebook) 2 marbles

Liquid Example (In Your Notebook) Corn syrup