Matter Notes Matter and Change

Chemistry, it’s all about matter! Matter is anything that has volume and mass. Examples of Matter: Earth, air, water, books, people, etc. NOT MATTER: Light, heat, radio waves, magnetic fields

Properties of Matter Focuses on the behavior and composition of matter Mass Color State (solid, liquid, gas) Ability to dissolve in water Conducts electricity

The Macroscopic View of Matter Matter that is large enough to be seen This is the beginning for all of our observations. We can get hints of what matter is made up of by these types of observations ….. but we need to look closer (smaller) to see the real structure and behavior

The Submicroscopic View You can’t even see this with the most powerful microscopes. ATOMS! This is where the majority of our study of chemistry is! This is why we use …

Models in Chemistry Because we can’t see the submicroscopic matter, we use models as a representation. There are models of what we think atoms look like and of how we think they behave. Scientific models are like model airplanes or cars, but these models have been tested and experimentally verified.

The Composition of Matter Qualitative – uses words of descriptions Color Heat Texture Quantitative – uses numbers and data Temperature Length Mass Volume

Types of Matter Pure Substances – are made of only one type of matter Elements Sodium Potassium Chlorine Compounds Sugar Salt Water

Mixtures A physical blend of two or more components that are NOT in a fixed proportion Examples: Iced tea Salt water Pizza Salad

Pure Substances Compounds Elements Two or more elements chemically combined Has different properties than the individual elements NaCl – table salt Elements The building blocks of matter The simplest form of matter 90 elements are naturally occurring Fewer than half the elements are abundant enough to play a significant role in chemistry.

Elements are organized on the periodic table. Element symbols are used to represent elements. Ag: Silver H: Hydrogen Formulas are combinations of chemical symbols and their amounts, used to represent compounds. H2O: Water Fe2O3: Iron (III) Oxide (rust)

Types of Mixtures Heterogeneous – composition is NOT uniform (pizza, salad, water and oil) Homogeneous – composition is uniform (Kool-Aid, motor oil)

Homogeneous Solutions Gas/Gas – air (oxygen and nitrogen) Liquid/Gas – soda (water and carbon dioxide) Liquid/Liquid – vinegar (water and acetic acid) Liquid/Solid – salt water (water and salt) Solid/Liquid – sponge (sponge and water) Solid/Solid – stainless steel (iron, chromium, and nickel) Alloy – metal solution

Parts of a Solution Solute – the substance being dissolved, present in a smaller quantity Solvent – substance doing the dissolving, present in a larger quantity

Aqueous Solution A solution in which the solvent is water

Physical Changes Alters the properties of the material without changing the composition Phase changes – boil, freeze, melt, condense Dissolve, cut, grind, bend, break split, crack, crush

States of Matter Solid Liquid Gas Plasma (ionized gas)

Changes in State Freezing – from a liquid to a solid Melting – from a solid to a liquid Evaporation – from a liquid to a gas Condensation – from a gas to a liquid

Physical Properties Properties of materials that can be observed without altering the material. We use these to separate mixtures. Solubility, melting point, boiling point, color, density, electrical conductivity, state (solid, liquid, or gas)

Volatility A volatile substance changes from a liquid to a gas at room temperature. Gasoline Alcohol

Chemical Properties Properties of materials that can only be observed when the substance changes composition Cannot be reversed without a chemical reaction Rusting, Flammability

Chemical Changes Alters the composition of the substance Creates a new substance Cannot be reversed without another chemical reaction Burning paper produces soot, carbon dioxide, and water vapor Combining and acid and a base forms water

Summary Matter Mixtures Pure Substances Hetero. Homo. Elements Compounds Physical Changes Chemical Changes

Density The ratio of the mass of an object to its volume Mass/volume (g/mL or g/cm3) Density of water = 1 g/mL Less dense objects float, more dense objects sink Increasing temperature decreases density (hot air rises)

Manipulating the Density Equation D = m/v m = Dv v = m/D

A bar of silver has a mass of 68. 0 g and a volume of 6. 48 mL A bar of silver has a mass of 68.0 g and a volume of 6.48 mL. What is the density of silver? D = m/v 68.0 g / 6.48 mL D = 10.5 g/mL

A copper penny has a mass of 3. 1 g and a volume of 0. 35 mL A copper penny has a mass of 3.1 g and a volume of 0.35 mL. What is the density of copper? D = m/v 3.1 g / 0.35 mL D = 8.9 g/mL

Signs of a Reaction: Gas formation (bubbles, fizzing) Color change Energy (heat/light released or absorbed) Precipitate formation – solid settling out of a liquid

Law of Conservation of Mass During any chemical reaction, mass is neither created nor destroyed, it is conserved the mass of the products (what is made from the reaction) the mass of the reactants (what goes into a reaction)

Energy in Reactions Endothermic Exothermic the capacity to do work; often observed as heat or light Endothermic Reaction absorbs heat Feels cold Ice packs Exothermic Reaction gives off heat Feels hot Hand warmers