Warm Up Convert 30 in to ft 2. Convert 19 g to kg 3. Convert 7.4 m to cm 4. Which is larger: 658 cm or 658 km? Agenda Turn in Lab Volume Go over Safety Quiz Notes Unit 1-3 Lab Density Homework Quiz Unit 1 Aug 28 - Online HW Unit 1 Sept 3 - Test Unit 1

Unit 1-3 How is Matter Classified? What does it mean to classify information? What does it mean to classify information? Why is it important to classify information? Why is it important to classify information?

Pure Substances Pure substance Pure substance  One type of element or a single compound, that has definite chemical and physical properties –Examples include copper, oxygen, and carbon dioxide –Elements, molecules or compounds

Pure Substances Elements Elements  Pure substances that contain only one type of atom (e.g. He, Li) –Some elements are diatomic (they are never found naturally by themselves. They have a “buddy”) H 2, O 2, N 2, Cl 2, Br 2, I 2, F 2 H 2, O 2, N 2, Cl 2, Br 2, I 2, F 2

Pure Substances Molecules Molecules  two or more atoms (usually the same elements)  Diatomic gasses (H 2, O 2, N 2, Cl 2, Br 2, I 2, F 2 ) –A molecule is the smallest unit of a substance that keeps all the physical and chemical properties of that substance –It can consist of one atom or two or more atoms bonded together –Example: Helium versus Hydrogen

Pure Substances Compounds Compounds  A substance made up of atoms of two or more different elements joined by chemical bonds (e.g. CO  A substance made up of atoms of two or more different elements joined by chemical bonds (e.g. CO 2 )   All compounds are molecules –Compounds can be made from their elements and also broken down into their components

Pure Substances ElementMolecule Compound or MoleculeMixture

Mixtures Mixture: A combination of two or more substances that are NOT chemically combined Mixture: A combination of two or more substances that are NOT chemically combined –Example: air is a mixture of nitrogen, oxygen, argon, and carbon dioxide –Example: pure water is NOT a mixture because H is chemically bonded to O to form H 2 O

Mixtures Homogeneous mixtures Homogeneous mixtures  When pure substances are distributed evenly throughout the mixture –The different components of the mixture cannot be identified by looking at it –Examples: air, gasoline, syrup

Mixtures Heterogeneous mixtures Heterogeneous mixtures  When pure substances are NOT evenly distributed throughout the mixture –You can see the different components in the mixture –Example: ice tea, cereal

Properties of Matter Chemical Properties: A property of matter that let it react with another chemical Chemical Properties: A property of matter that let it react with another chemical –Chemical properties can only be identified by trying to cause a chemical change

Properties of Matter Physical Property: A property that can be determined without changing the nature of the substance Physical Property: A property that can be determined without changing the nature of the substance –Example: sugar’s physical properties would include that it is solid, white –More examples: State of matter State of matter Melting points Melting points Boiling point Boiling point Mass and volume Mass and volume

Properties of Matter Density = mass/volume Density = mass/volume g/cm 3 g/cm 3 The density of an object is the same no matter its volume The density of an object is the same no matter its volume -Density is also a physical property of matter that can be used to identify substances (stuff per space)

Density Example Problems 1. What is the density of an object that weights 2200g and has a volume of 100cm 3 ? 2. Gold’s density is 19.3g/cm 3 If a gold bar has mass of 150g what is its volume? 3. Find the density of this cube. Mass = 30g Mass = 30g

Density Lab Follow the lab procedure to find the volume of pennies and metal cylinders Follow the lab procedure to find the volume of pennies and metal cylinders Find the unknown materials used to make the cubes by finding its density Find the unknown materials used to make the cubes by finding its density Lab due before class is over Lab due before class is over Unit 1 Density WS due at the end of next class Unit 1 Density WS due at the end of next class

Mixture Vs. Compound Review A mixture is composed of two or more substances that are physically mixed A mixture is composed of two or more substances that are physically mixed Properties of mixtures reflect the substances it contains Properties of mixtures reflect the substances it contains Mixtures can have varying proportions Mixtures can have varying proportions Mixtures can be separated based on the physical properties of the substances Mixtures can be separated based on the physical properties of the substances A compound is composed of two or more elements chemically joined A compound is composed of two or more elements chemically joined Properties of compounds have different properties than the elements that make them up Properties of compounds have different properties than the elements that make them up Compounds have definite proportions Compounds have definite proportions Compounds can only be separated into its components through chemical change Compounds can only be separated into its components through chemical change