Introduction to Chemistry Chapters 1 and 2 Introduction to Chemistry Matter and Change
What is Chemistry?
What is Chemistry? The study of matter, its composition, properties, and the changes it undergoes. The interaction between matter and energy
What is Chemistry? Applied Chemistry using chemistry to attain certain goals Technology Pure Chemistry gathers knowledge for knowledge sake
Matter and Its Properties Anything that has mass and volume is considered to be a form of matter Mass: The amount of matter in an object. Volume: The space that matter takes up.
Properties and Change in Matter Physical Properties: can be observed and measured without changing the substance’s composition.
Physical Properties Conductivity Color Density Melting point Boiling point Malleability Ductility
States of Matter
Physical Changes Changes the appearance, without changing the composition of the matter. Melting, dissolving, boiling
Phase Changes are Physical Changes Solid: definite volume and shape Liquid: definite volume, indefinite shape gas: indefinite volume and shape Solid Liquid Gas
Classification of Matter What are Mixtures?
Mixtures Made up of two or more substances physically combined. Each part keeps its own individual properties. Examples: Air, wood, tea, Consist of more than one kind of matter. Do not have a chemical formula.
Orange juice is a mixture of: Water – H2O Fructose – C6H12O6 Citric Acid –C6H8O7 and many more compounds… Most things around us are mixtures
Mixtures Heterogeneous: Nonuniform composition. Chocolate chip cookie, gravel, soil. Homogeneous: Same composition throughout. Koolaid, air, tea called solutions.
Solutions Homogeneous mixture called a solution Mixed molecule by molecule Can occur between any state of matter. Solid in liquid Koolaid Liquid in liquid 3% hydrogen peroxide Gas in gas air Liquid in gas water vapor Gas in liquid soft drink Solid in solid brass
Separating Mixtures
Separating Mixtures Components are physically mixed Use differences in the physical properties of components of the mixture to separate the mixture Solubility Density Boiling point Molecular structure
Filtering and Decanting
Filtering
Magnetism
Distillation
Chromatography the separation of a mixture by passing it in solution or suspension or as a vapor (as in gas chromatography) through a medium in which the components move at different rates.
Crystallization
Classification of Matter Pure Substances
Classification of Matter Pure substance pure form of matter consists of – an element or a compound. Has a chemical formula. Carbon dioxide – CO2 Hydrogen – H2 Sodium – Na Water – H2O
Pure Substances?
Basic Building Blocks of Matter Atoms Elements Compounds are the basic units of matter The smallest unit of an element that maintains the properties of that element.
Basic Building Blocks of Matter Atoms Elements Compounds pure substances made of only one type of atom Na H2 Pb O2 S8
Most of the elements do not exist in their elemental state, but exist in compounds. Why do you think this is? 2 Na + Cl2 2 NaCl
The most common element is hydrogen, more than 90% of the atoms in the known universe are hydrogen. Oxygen and silicon make up more than 70% of the Earth’s crust. Living things are composed primarily of four elements: carbon, hydrogen, oxygen, and nitrogen.
Compounds Substances made from the chemical bonding of two or more different elements. ( NaCl H2O MgO ) Substances that can only be broken down by chemical methods. Has completely different properties from the constituent elements that make it up.
Molecule: a group of atoms held together by bonds Molecule: a group of atoms held together by bonds. It may contain 2 or 2000 atoms
Hydrogen atom Carbon atom Oxygen atom Vitamin C – Ascorbic Acid
Vocabulary Molecule Compound two or more atoms that can be the same or different Compound – two or more different kinds of atoms
Homogeneous Mixture (solution) MATTER yes Can it be separated no by physical means? MIXTURE PURE SUBSTANCE yes Is the composition uniform? no yes Can it be decomposed by chemical means? no Homogeneous Mixture (solution) Heterogeneous Mixture Different atoms: Compound Same atoms: Element
(a) Atoms of an element
(b) Molecules of an element
Which is it? PURE SUBSTANCE? MIXTURE? ELEMENT? MOLECULE? COMPOUND?
Which is it? PURE SUBSTANCE? MIXTURE? ELEMENT? MOLECULE? COMPOUND?
Which is it? PURE SUBSTANCE? MIXTURE? ELEMENT? MOLECULE? COMPOUND?
PURE SUBSTANCE? MIXTURE? ELEMENT? MOLECULE? COMPOUND?
PURE SUBSTANCE? MIXTURE? ELEMENT? MOLECULE? COMPOUND?
PURE SUBSTANCE? MIXTURE? ELEMENT? MOLECULE? COMPOUND?
ATOM, ELEMENT, MOLECULE, COMPOUND? B C A D E
ATOM, ELEMENT, MOLECULE, COMPOUND? B C A D E
Chemical Changes
Chemical Reactions Reactants – starting material(s) Products - ending material(s) The reactants turn into the products. Reactants Products Iron + Sulfur Iron sulfide
Chemical Properties Observable only when one substance reacts with another substance. A chemical property of O2 is that it supports combustion • CH4 + 2O2 CO2 + 2H2O Methane and oxygen produce carbon dioxide and water
Chemical Properties Reactivity with acids Reactivity with bases Reactivity with oxygen Reactivity with hydrogen Reactivity with water Reactivity with …………… etc. etc. etc. ……. Are there more chemical or physical properties of matter ?
Chemical Changes •Creates a new form of matter. •A chemical reaction occurs.
Indications of a chemical reaction Energy is absorbed or released Color change
Indications of a chemical reaction Gas released A precipitate is a solid that forms during a reaction between two solutions and sinks.
Conservation of Mass Mass and matter can not be created or destroyed in ordinary (non nuclear) changes. All the mass can be accounted for. The total amount of mass remains the same in any chemical change so the mass of the reactants is equal to the mass of the products
Law of Conservation of Mass
water Sodium
Sodium reacts violently with water Sodium reacts violently with water. All the matter is still there, just in another form. The energy has simply changed from chemical potential energy to heat and light energy.
Periodic Table and Elements
Which are solids, liquids, gasses?
Symbols of Elements First letter is always capitalized Second letter is never capitalized CO vs. Co Latin and German origins of some element names
Symbols of Elements Sb – antimony K – potassium Na – sodium Pb – lead Sn – tin Fe – iron W – tungsten Ag – silver Au – gold Cu – copper Co – cobalt H – hydrogen N – nitrogen F – fluorine C – carbon O – oxygen Ca – calcium Hg mercury
Periodic Table Speller https://www.bgreco.net/periodic/