Matter and Elements Chemistry 1405

Classification of Matter Matter is anything that occupies space and has mass We can classify matter based on its state and its composition whether it’s solid, liquid, or gas its basic components

States of Matter Solid – has a definite shape and definite volume. Liquid – has an indefinite shape and a definite volume. A liquid takes the shape of its container. Gas – has an indefinite shape and an indefinite volume. A gas assume the shape and volume of its container.

Matter Physical property –characteristic of a substance that can be observed without changing the substance into another substance. E.g Color, odor, taste, size, physical state, boiling point, melting point density, Texture, Mass, volume, weight. The appearance of a substance may change while a physical property is being determined, but the substance’s identity will not. For example, the melting point of a solid cannot be measured without melting the solid, changing it to liquid. Physical properties – color, odor, taste, physical state, boiling point, melting point, sublimation point, deposition point, density. Chemical property – reaction with air, oxygen, acid, base, decomposition. Chemical properties are influenced by temperature and pressure.

Matter Chemical property – a characteristic of a substance that describes the way the substance undergoes or resists change to form a new substance. Chemical Properties describe the ability of a substance to form new substances either by reaction with other substances or by decomposition.

Properties Physical Chemical Color Odor Porosity Boiling point Solubility Melting point Chemical Reactivity Flammability Stability Rusting Reacts with air

Classify each of the following as a physical or chemical property 1. aluminum has a silvery color. 2. The mass of lead 3. Gold has a density of 19g/cm3 4. Magnesium burns brightly when ignited. 5. Milk turn sour. 6. water boils at 1000c 7. Iron and oxygen form rust. Physical 5. Chemical Physical 6. Physical Physical 7. Chemical Chemical

Intensive and Extensive Property Intensive property – independent of the amount of substance present. Examples – Temperature, color, Melting point and density Extensive property – depends on the amount of substance present. Examples – mass, volume, length

Matter Physical change – process in which a substance changes its physical appearance but not its chemical composition. Examples: Melting ice Cloud formation Making rock candy Cutting into smaller pieces

Gas phase Evaporation Condensation Sublimation Deposition Melting Freezing Solid phase Liquid phase

Matter Others? Burning Food digestion Plant growth Healing of a wound Chemical change – process in which a substance undergoes a change in chemical composition. A new substance is formed. Burning Food digestion Plant growth Healing of a wound Rust Fermentation Others?

Chemical Reaction or Physical Change? If the composition does not change, the change is physical. If the composition does change, the change is chemical. It can be very difficult to recover the original material in a chemical change.

Classification of Matter by Composition Matter whose composition does not change from one sample to another is called a pure substance physical combination of two or more pure substances in which each substance retains its own chemical identity. mixture Classification of Mixtures Homogeneous mixtures are mixtures that have uniform composition throughout Heterogeneous mixtures are mixtures that do not have uniform composition throughout

Types of Mixtures Heterogeneous Homogeneous Two or more visibly distinct phases. Each phase has different properties. Examples? Homogeneous Only one visibly distinct phase. The phase has the same properties throughout. Examples? Heterogeneous mixtures: rocks, soil, wood, salt/pepper, sand/water, oil/vinegar. If shaken is the oil/water mixture still heterogeneous? Yes – it is just emulsified. Milk is a heterogeneous mixture. Homogeneous mixture – cool aide, salt water (but not necessarily sea water), older “silver” coins – 90% silver, 10% Cu.

Types of mixture A homogeneous mixture has a constant composition throughout; it always has a single phase. Examples of homogeneous mixture Sugar and water Mixture. Milk Motor oil and gasoline are homogeneous mixture of liquids. Mixture of copper and Gold

Mixtures A mixture is a combination of two or more pure substances in which each substance retains its individual chemical properties. Mixtures can be separated by physical means. Example of a mixture sand and water mixture, sand and iron fillings.

Pure Substance or Mixture Elements are pure substances. Elements are made from atoms. Cannot be broken down into simpler substances by chemical or physical means. Building blocks for all other types of matter.. Each has its own name, symbol, and unique characteristics.

Three Types of Elements Metals :A metal is a good conductor of heat and electricity. Nonmetals : A non metal is not a good conductor of electricity. Metalloid: A metalloid has properties that are intermediate between those of metals and nonmetals

The periodic Table of Elements The periodic table organizes the elements into a grid of horizontal rows called periods and vertical columns called groups or families.

ELEMENTS OF THE PERIODIC TABLE Metals, Nonmetals, and Metalloids

= Alkali metals = Alkali earth metals = Noble gases = Halogens = Lanthanides = Actinides = Transition metals add pictures of elements from text Tro: Chemistry: A Molecular Approach, 2/e

Symbol Element Name   Ag Silver* Be Beryllium Cr Chromium Al Aluminum Br Bromine Cu Copper* Ar Argon C Carbon F Fluorine Au Gold* Ca Calcium Fe Iron* B Boron Cl Chlorine H Hydrogen Ba Barium Co Cobalt He Helium

Symbol Element Name   Hg Mercury* Na Sodium* Pt Platinum I Iodine Ne Neon S Sulfur K Potassium* Ni Nickel Si Silicon Li Lithium O Oxygen Sn Tin* Mg Magnesium P Phosphorus U Uranium N Nitrogen Pb Lead* Zn Zinc * Latin name

Pure Substance or Mixture Compounds are also pure substances. They are a chemical combination of two or more atoms. Can be broken down into constituent atoms using chemical but not physical means. Have a definite, constant elemental composition. Rules exist for combining atoms into compounds.

Chemical Formulas Molecular Compounds – formula represents composition of molecules making up compounds. Ionic Compounds – Formula represents ratio of ions in the compound since these are not considered molecules. A formula unit is used to describe the smallest ratio between ions. NaCl

Common Compounds Baking soda NaHCO3 Sodium carbonate Epsom salt MgSO4 Magnesium sulfate Clorox NaClO Sodium hypochlorite Lime water Ca(OH)2 Calcium hydroxide in water Vinegar CH3COOH Acetic acid Table salt NaCl Sodium chloride Chalk CaCO3 Calcium carbonate Ethyl alcohol C2H5OH Ethanol Ammonia NH3

Pure Substance or Mixture Physical combination of two or more substance Variable composition Properties vary as composition varies Components can be separated using physical means. Pure Substance Only one substance is present Definite and constant composition. Properties are always the same under a given set of conditions. Cannot be separated by physical means.

Mixture or Pure Substance? Crystalline sugar Sugar water solution Solid gold bullion Steel Milk

Pure Substances vs. Mixtures Identify these as chemically and physically heterogeneous or homogeneous: Glass of water at room temperature Salad dressing Glass of kool-aid. Glass of ice water