Matter and Change Mrs. McGuire Chemistry

State (solid, liquid, gas) Composition A) Classification of Matter Some Criteria for the Classification of Matter Properties State (solid, liquid, gas) Composition

-Depend on amount of matter. Ex: mass, length, and volume Properties Intensive -Do not depend on amount of matter. Ex: color, odor, luster and conductivity Extensive -Depend on amount of matter. Ex: mass, length, and volume

Intensive and Extensive Properties Sulfur

Physical: observed without changing the composition of the substance. Properties Physical: observed without changing the composition of the substance. Chemical: the ability of a substance to undergo a specific chemical change

REGENTS QUESTION Which statement describes a chemical property of sodium? (1) Sodium has a melting point of 371 K. (2) Sodium has a molar mass of 23 grams. (3) Sodium can conduct electricity in the liquid phase. (4) Sodium can combine with chlorine to produce a salt

Examples of Physical Properties Color, odor, hardness, density, melting point, boiling point, state, solubility.

Example: Physical Properties Substance State Color Melting Point (C°) Boiling Point (C°) Density (g/cm3) Oxygen O2 Gas Colorless -218 -183 0.0014 Mercury Hg Liquid Silvery-white -39 357 13.5 Bromine Br2 Red-brown -7 59 3.12 Water H2O 100 1.00 Sodium Chloride NaCl Solid White 801 1413 2.17

fixed shape and volume, incompressible Liquid States of Matter Solid fixed shape and volume, incompressible Liquid fixed volume, takes the shape of its container Gas takes the volume and shape of its container

STATES of matter

Bromine Gas (Vapor) Liquid

Change of Phase Condensation gas  liquid Freezing liquid  solid Deposition gas  solid Melting solid  liquid Evaporation liquid  gas Sublimation solid  gas Boiling: Evaporation occurring beneath the liquid’s surface.

BONUS REGENTS QUESTION Which physical change is endothermic? (1) CO2(s) → CO2(g) (2) CO2(g) → CO2(ℓ) (3) CO2(ℓ) → CO2(s) (4) CO2(g) → CO2(s)

Chemical Properties and Chemical Changes Is changing phase a physical or chemical change? ___________________Explain:

H2O composition is fixed- compound Gaseous Phase Liquid Phase

Draw at least five particles to represent the phase of the product. REGENTS QUESTION Coal is a fuel consisting primarily of carbon. In an open system, the carbon that burns completely in air produces carbon dioxide and heat. This reaction is represented by the balanced equation below. C(s) + O2(g) → CO2(g)+ heat Draw at least five particles to represent the phase of the product.

Chemical Properties The ability of a substance to transform into a new substance (to undergo a chemical change). Example: Magnesium reacts with oxygen to form magnesium oxide.

Magnesium Mg

Burning of Magnesium 2Mg+ O2 2MgO

REGENTS QUESTION Which term identifies a type of chemical reaction? (1) decomposition (2) sublimation (3) Distillation (4) vaporization

Physical Changes Physical change: a change in the physical properties of a substance. Composition does not change. May be reversible or irreversible. Examples: Reversible: Liquid water < -- > solid water Irreversible: Tearing a piece of paper

Chemical Change A change that produces matter with a different composition than the original matter. Atoms rearrange themselves into new combinations.

Burning of Methane CH4 +2O2 CO2 + 2H2O

Burning of Methane CH4 + 2O2 CO2 + 2H2O

Recognizing a Chemical Change energy exchange production of a gas color change formation of a precipitate

Formation of a Precipitate Cu(OH)2 Precipitate

The Law of Conservation of Mass (Antoine Lavoisier) In any chemical or physical change, mass is neither created or destroyed Mass is CONSTANT

Classification of Matter (by composition)

Matter that has a uniform and definite composition. (Pure) Substance Matter that has a uniform and definite composition. Elements: organized on a periodic table, unique name, one, two or three letter symbol Compounds: two or more elements combined chemically

REGENTS QUESTION All atoms of uranium have the same (1) mass number (2) atomic number (3) number of neutrons plus protons (4) number of neutrons plus electrons

REGENTS QUESTION Which substance can not be broken down by a chemical change? (1) ethane (2) silicon (3) Propanone (4) water

c) Elements and Compounds Pure substances Elements can NOT be decomposed by chemical means, but compounds can.

The simplest substances. Can not be separated into simpler substances. Elements The simplest substances. Can not be separated into simpler substances. Building blocks of all matter. More than 100 known elements. Represented by chemical symbols.

Chemical Symbols of Elements System started by Jons Berzelius (Sweden, 1779-1848) One or two first letters of name of the element. Many elements names have roots from: Latin, Greek, mythology, geography, names of scientists.

Examples: Americium, Am Einsteinium, Es Bromine, Br Helium, He Lead(Plumbum), Pb Niobium, Nb Iron (Ferrum), Fe Mendelevium, Md

Compound A substance that contains two or more elements chemically combined. Compounds have different properties from the individual substances. (Ex: H2O)

Example: H2O

The law of definite proportions states that a compound is always composed of the same elements in the same proportions.

Percent composition

If composition is fixed and may not changesubstance Substance or mixture? If composition is fixed and may not changesubstance

REGENTS QUESTION Which sample of matter is a mixture? (1) Br2(ℓ) (2) KBr(s) (3) K(s) (4) KBr(aq)

Uniform composition and properties throughout Mixture: a physical blend of two or more substances that are not chemically combined. Homogeneous: Uniform composition and properties throughout Heterogeneous two or more sustances are physically combined and retain their original properties

A physical blend of two or more substances. Mixtures A physical blend of two or more substances.

Mixtures Homogeneous Heterogeneous

Example: Stainless Steel A homogeneous mixture of: -Iron (Fe) -Chromium (Cr) -Nickel (Ni)

Heterogeneous Mixtures Example: Oil and vinegar Non-uniform composition throughout the mixture Two or more phases.

Example: Gaseous Mixture Elements argon and nitrogen and a compound (water vapor). Choice ?

Mixtures can be physically separated. Note: Mixtures can be physically separated. Mixtures exhibit physical properties similar to the components of the mixture.

Separation Methods Use differences in the physical properties of the components of the mixture.

Example: Separate iron filings from sulfur using a magnet.

Filtration: separates a solid from a liquid in a heterogeneous mixture

Distillation: -separate dissolved solids from a liquid -uses boiling and condensation.

Distillation of Crude Oil (Refining) Crude Oil is a mixture of Hydrocarbons

BONUS REGENTS QUESTION Which formula represents a hydrocarbon? (1) CH3I (2) CH3CH3 (3) CH3NH2 (4) CH3OH

Distillation of Crude Oil

REGENTS QUESTION A mixture consists of sand and an aqueous salt solution. Which procedure can be used to separate the sand, salt, and water from each other? (1) Evaporate the water, then filter out the salt. (2) Evaporate the water, then filter out the sand. (3) Filter out the salt, then evaporate the water. (4) Filter out the sand, then evaporate the water.