Chemistry 1010 Notes PDF

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Teacher: Lilia White --- Very hard class to take notes based on power point slides and lectures.
Notes cover: Molecular Reasons, Significant Figures, Atoms/Elements, Molecules/Compounds/Chemical Reactions, and Chemical Bonding...

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Chemistry 1010 Notes: I-cklicker code: AB

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There is nothing that you can hold touch smell that is not made of chemicals. Chemicals make up virtually everything in this world Chemicals are made up of tiny particles that you cannot see with the naked eye (elements) Combinations of elements/molecules determine how matter behaves. Structure of the molecules determines what properties they become. Ie. water, steel or other such items.

Chapter 1: Molecular Reasons ● ●

Chemists use the scientific method - a way to understand and learn that emphasizes observations and experimentation to produce knowledge. Experimentations are designed to

Scientific Method: A scientist’s problem solving process Observations: involve measuring or description of some aspect of nature--Qualitative or Quantitative. Hypothesis: Are tentative interpretations of the observations Laws: Summarize the results of a large number of observations Theories: Are models that explain and give the underlying causes for observations and laws.

Law of Conservation of Mass: In a chemical reaction, matter is neither created nor destroyed.

Law of Constant Composition: all samples of a compound have the same proportions of their constituent elements. Dalton’s Theory: all matter consists of small indestructible particles called atoms. Philosophers: Plato: matter- infinitely divisible Democritus: indivisible particle “atomos” Philosophers- Truth is revealed through logic and debate. Scientists- Truth is revealed through experimentation Alchemists of Alchemy: a group of philosophers who were the beginning of scientists. They tried transmutation of base metals into gold. As well as discovered the “elixir of life.” Metallurgy

Mysticism and secrecy slowed down the process Beginning of Modern ScienceThe scientific revolution 1543 Galileo Galilei's ideas contradicted the teachings in aristotle and the catholic church. Robert Boyle’s sceptical chymist criticized Greek ideas centered on four elements while further developing the concept of elements.

Matter: everything that you occupies space and energy. Composed of atoms ● ●

Mass: amount of matter in an object. Matter is divided into two groups- Pure substances (made of one type of particle) or mixture (made of multiple types of particles)

Pure substances: ● Elements cannot be decomposed into simpler forms by any amount of chemical transformation ● Compounds are composed of two or more elements of defined portions

Diatomic Elements- Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, Iodine Polyatomic Elements- Phosphorus, Sulfur Classifications of mixtures- mixture -Heterogeneous ie. fruits (1made of pure substances whose presence can be seen 2 ), Homogeneous ie. shakes (made of multiple substances that appear to be one substance) Homogeneous mixtures are called solutions

States of Matter: Solid: Incompressible, fixed volume, fixed shape Liquid: Incompressible**, fixed volume, variable shape Gas: Compressible, variable volume, variable shape ** Liquids are very slightly compressible- usually considered incompressible for the convenience of studying. In a physical change matter changes its appearance but not composition.

In a chemical change the matter changes its composition to be another substance (forms new molecules)

Law of Constant Composition: all samples of a compound have the same proportions of their constituent elements. -All matter is composed of indivisible particles called atoms that cannot be created or destroyed.

Rutherford’s Interpretation of the nuclear model: 1. The atom contains a tiny dense center called the nucleus. 2. The amount of space taken by the nucleus is only about 1/10 trillionth the volume of the atom

Chapter 2:

Observations: Qualitative- sweet, hot, cold does not have numbers. Quantitative- is a measurement (has a number and a unit) Scientists report measured quantities in a way that reflects the uncertainty associated with the measuring device used. Significant digits: all certain numbers and the first estimated numbers is reported measurement are called significant figures. Precision depends on the precision of the measuring device. The greater the precision of the measurement, the greater the number of significant figures. Accuracy and precision: You want High accuracy and high precision. Significant figures represent the precision of the measurement. ● Whole numbers have unlimited number of significant figures. ● ALL non-zero digits are significant ● Interior Zeros (zeros between two numbers) are significant ● Trailing Zeros after the decimal point are significant ● Leading Zeros are Not significant ● Zeros at the end of a number without a decimal point are ambiguous and should be avoided in scientific notation Significant figures: ● Multiplication and Division rule: The result of multiplication or division carries the same number of significant figures as the factor with the fewest significant figures.

● Addition and Subtraction: (think in terms of decimal places) the final answer will have the same amount of decimal places as the least precise quantity. For calculations involving multiple steps. Round ONLY the Final answer.

Standard Scientific Notation Units: ● Units are fixed, agreed-upon quantities to which other quantities are compared ● A number in association with a unit is a representation of a measurement. ● Length-Meters (m) ● Mass - Kilograms (kg) ● Time- Second (s) ● Temperature - Kelvin(k) Mass: Is a quantity of matter Derived SI units: ● Volume: measure of space - Length x width x height

Dimensional analysis: Math equation--- (underlined means crossed out) Given unit x desired unit/given  unit =desired unit

Density: a measure of how much mass is in a given amount of volume More molecules provide a greater mass Density = Mass/ Volume ● It depends on the type of material!!!! ➔ Units for Density: ● g/cm^3 (cubed) or g/mL or g/L Cone: ⅓ pie(r)^2h Cylinder: pie(r)^2h

Chapter 3: Atoms and Elements ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●

The simplest form of a substance is known as an element. A molecule is the smallest unit of a compound. Compounds are smaller than molecules. An atom is the smallest identifiable unit of an element The number of Protons in the nucleus are equal to the number of electrons in an atom Cations: ions that have a positive charge Anions: ions that have a negative charge -forms when atom gains charge Ions with opposite charges attract - therefore cations and anions attract each other. Neutrons are almost as massive as protons but have no charge The number of neutrons in an element can vary resulting in Isotopes The sum of Neutrons and Protons in an atom is called the “ Mass Number” All isotopes of an element are chemically identical - undergo the exact same chemical reactions All isotopes of an element have the same number of protons Isotopes of an element have different numbers of neutrons. Isotopes of an element have different masses. Isotopes are identified by their mass numbers Mendeleev listed the known elements in the order of increasing atomic mass He noticed that certain similar properties would recur in a periodic fashion, a repeating pattern. The Periodic Law - when the elements are arranged in order of increasing atomic mass, certain sets of properties recur periodically

Bohr Model - how electrons behave in atoms Electrons travel in orbits around the nucleus n- the orbit’s quantum number Max number of electrons determined by the value of the quantum number The number of electrons outside the nucleus define elements chemical behavior. Number of protons > ID atom

Families of Elements

Avogadros # - 1Mol = 6.022x10^23 1Mol = the number of things equal to the number of 12 grams of a particle Atomic mass: mass of one atom (in amu or atomic mass units) Molar mass(MM): mass of one mol. or molecules, grams.

Atomic Mass: Mass of one atom Molar Mass: Mass of one mole or (avogadro's number 6.022x10^23) Amu: unit for mass of one atom

Chapter 4:

A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Chemical compounds and Chemical formulas 1 molecule H2O Chemical formulas: ● Indicate the elements present in a compound and the number of atoms of each element. ● If we change the subscripts in a chemical formula, we no longer represent the same compound. ● -H20 is water ● - H2O2 is hydrogen peroxide Chemical Bonds: ● Compounds are made of atoms held together by chemical bonds ● Elements with unstable electron configurations form compounds with other elements to gain stability ● Sharing of electrons - molecular compounds ● Transfer of electrons - Ionic compounds ● Electrons shared equally - pure (nonpolar covalent bond) ● Electrons shared unequally - polar covalent bond ● Electrons transferred - Ionic bond Molecular compounds: ● Contain only nonmetals ● Electrons in a bond are shared but not always equally ● The resulting bond is covalent. ● Subscripts represent the actual number(s) of each kind of atom in the molecule – ● The properties of molecular compounds depend on the molecules that compose them. ● The composition of molecules is responsible for what we observe and experience.

Dissociation: ● We know that Ionic compounds dissociate when they dissolve in water because the solution conducts electricity

Ions: Species with an electrical charge monoatomic Ion: ANIONS

Positive Ions: CATIONS In a chemical formula the electrical charges of the positive ions (cations) must equal the sum of the charges of the negative ions (anions). Monoatomic Anions: ● charge is = 8 - group number ● Names = root of element names + ending => - ide ● E.g. N is nitrogen, charge = 8-5=3, so N^3- is nitride Monoatomic Cations: ● Charge= main group ● Invariant charge: Names= same as metal ● Variable charge: Names metal name (charge)

Naming Molecular Compounds: ● The more metallic element is listed first and is followed by the less metallic element. ● Prefixes are used to show the number of atoms of the element that are present. ● The mono- prefix is not used on the first element. Formula (molecular) Mass vs Molar Mass Molecular Mass: is a sum of all the masses of each element combined. Molar Mass H2O = mass of 1 mole H2O molecules Molar mass Molar mass is the sum of the molar masses of all the atoms in its chemical formula: MM = 2(1.01 g H) + 16.00 g O = 18.02 g/mol Mass of 1 H2O Molecule = 2(1.01 amu H) + 16.00 amu O = 18.02 amu

Stoichiometry: ● The study of the numerical relationship (ratio) between chemical quantities in a balanced reaction is called stoichiometry. ● The coefficients of a balanced chemical equation are used as conversion factors in chemical calculations to answer the question ● Limiting reactant: the amount of product will depend on the amount of the reactant that gets consumed first. VOCABULARY NEED TO KNOWS: ● Subscript: A  type of lettering form written lower than the things around it. ● Coefficient: A  constant term related to the properties of a product

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Law of Conservation of Mass: In a chemical reaction, matter is neither created nor destroyed. Molar Mass: Mass of one mole or (avogadro's number 6.022x10^23) Molecule: is the smallest unit of a compound Atom: An atom is the smallest identifiable unit of an element Word Equation:  a chemical reaction expressed in words rather than chemical formulas. Skeleton (unbalanced) Equation: You put chemical formulas in place of chemical names. Balanced Equation: The number of the different atoms of elements in the reactants side is equal to that of the products side. Stoichiometry: The study of the numerical relationship (ratio) between chemical quantities in a balanced reaction

Lewis Theory: A pattern of valence electron distribution in the molecule VSEPR Theory: Predicts the geometry of the molecule Lewis formulas of molecules ● Shows pattern of Valence electron distribution in the molecule ● Useful for understanding the bonding in many compounds ● Allows us (with VSEPR model) to predict shapes of molecules Ionic bonds: Valence electrons are transferred. Covalent bonds: Valence electrons are shared. Lewis and Bonding: ● Bond formation results in formation of full outer Bohr orbits. ● Because this stable configuration typically involves eight electrons, this is commonly known as the OCTET rule Types of electron pairs: The electrons between two atoms are called bonding pairs Electrons on a single atom are called lone pairs ONLY BONDING PAIRS count toward octet rule!!! Writing Lewis Structures 1. Write skeletal structure of the molecule 2. Determine the total number of valence electrons for the molecule 3. Attach central atom to the surrounding atoms with pairs of electrons and subtract from the total 4. Place the electrons as dots to give octets to as many atoms as possible 5. If the central atom has not obtained an octet, for multiple bonds as necessary to complete its octet.

Lewis Theory: a model for chemical bonding - explains why atoms combine as they do. VSEPR Theory: predicts the geometry of the molecules. Writing Lewis Structures 1. Write the skeletal structure of the molecule. 2. Determine the total number of valence electrons for the molecule. 3. Attach central atom to the surrounding atoms with pairs of electrons and subtract from the total 4. Place the electrons as dots to give octets to as many atoms as possible. 5. If the central atom has not obtained an octet, form multiple bonds as necessary to complete its octet.

THERE ARE 3 TYPES OF MOLECULES OR IONS THAT ARE EXCEPTIONS TO THE OCTET RULE 1. Electron deficient molecule 2. Molecules with an odd number of electrons 3. Molecules with expanded valence shells The Shape of Molecules: Valence Shell Electron Pair Repulsion Theory (VSEPR) An electron group can be: 1. A single bond- a bonding pair of electrons 2. A non bonding pair of electrons 3. A double bond 4. A triple bond 5. A single unpaired electron 2 electron groups - 180 degrees (linear) 3 electron groups - 120 degrees (Trigonal) 4 electron groups - 109.5 degrees (tetrahedral)

The Ideal Shape ● Three-dimensional geometry ● Greatest angle (minimum repulsions, maximum distance) between four bonding electron pairs on a central atom is tetrahedral. ● It is important to distinguish between electron geometry and molecular geometry.

Electron Geometry: determined by the total number of electron groups around a central atom Molecular Geometry: determined by the number of bonding groups on a central atom.

Non Polar covalent bonds: atoms have equal strength and will share the electrons. Polar covalent bonds: one atom has a stronger charge and will not share the electrons equally aka: Electronegativity A dipole is a material with positively and negatively charged ends Dipole moment - “m” is a measurement of the the molecules polarity....