CHEMISTRY 2: Stoichiometry, Chemical Bonds Flashcards
Is the study of quantitative aspects of chemical formulas and chemical reaction
Stoichiometry
Amount of any substance that contains the same number of elementary entities as there are atoms in 12g of 12c
Mole
Is the mass per mole of entities (atoms, molecules or formula units)
Molar Mass
Familiarize stoich map
GO NAAA
Mass → Mole = Mass/Molar Mass
Particles→ mole = Atoms/Avogadro’s number
Mol → Mass = Mol x Molar Mass
Mol → Particle = Mol x Avogadro’s number
palabas ang times, paloob divide (arrow)
→ Is the quantitative relationship between the amounts of reactants used and amounts of products formed in a reation
→Expressed in balanced equationExpressed in balanced equation
Chemical Stoichiometry
Formula of Percent Yield?
% yield = Actual yield/Theoretical yield (100)
→ The amount of product that could possibly be produced in a given reaction
→ Calculated according to the starting amount
Theoretical yield
→ The amount of product actually obtaiend in a chemical reaction
Actual yield
→ A chemical reactant that limits the amount of product that is formed
Limiting reactant
→ Gives smallest yield of product calculated from the reagents available
Limiting agent
→ Is the reactant in a chemical reaction with a greater amount than necessary to react completely with the limiting reactant
Excess reactant
Formula and Composition
Shows the simplest ratio of elements in a molecular compound
Empirical formula
Shows the number and type of atoms that make up a molecule
Molecular formula
Atoms combine, electron distribution changes
Chemical Bonds
What are the 3 types of chemical bonds?
- Covalent bond
- Ionic bond
- Metallic bond
3 types of chemical bonds
Results from shairng of electrons between atoms. Found between nonmetals
Covalent bonding
3 types of chemical bonds
Results from transfer of electrons from a metal to a non metal
Ionic bonding
3 types of chemical bonds
Outer electrons move throughout solid and holds nuclei together and the compound is only composed of metals
Metallic bond
Allows us to draw shape of a molecule which helps us to understand its properties
Lewis Structure
→ Some atom atomd in the third row of the periodic table and beyond can acommodate 4 paiard of electrons
→ Termed a central atom and the atoms bonded to it are called outer atoms
Hypervalent Atoms
→ A tool used to represent certain types of molecular structures
→ Arises when no single conventional model using only single double or triple bond can account for all the observed properties of the molecule
Resonance
→ Used to evaluate non-equivalent Lewis structures
→ no. of valence electron in free state -no. of nonbonding electrons - no. of bonds
Formal charge
Is a set of empirical rules for predicting a molecular geometry using, as input, a correct lewis dot representation
Valence Shell Electron Pair Repulsion (VSEPR)
Distribution of regions of high electron density around the central atom
Electronic geometry
Arrangement of atoms around the central atom
Molecular geometry
T or F
If lone pairs are present, molecular and electronic geometries are samae
F (they are different, same if no lone pairs are present)
Dipole momements for all bonds cancel out
Nonpolar molecule
Dipole moments for all bonds don’t cancel out/ has net dipole moment
Polar molecule
→ Is the force that holds molecules together
→A form of “stickiness” between molecules
Intermolecular Force of Attraction (IMFA)
What are the 4 types of Intermolecular Forces of Attraction
- London Dispersion Forces
- Dipole-dipole forces
- Hydrogen bonding
- Ion-Dipole Forces
4 Types of Intermolecular Forces of Attraction
→ Called “Induced dipole forces or dispersion forces”
→ Temporary dipole attraction between non polar molecules that form due to shifting electrons
→ Electrons concentrate in one region, which results in temporary dipole that disappears when the electrons shift again
→ Temporary partially negative charge and partially positive charge forms
London Dispersion Forces
only type of IMF between nonpolar molecules (weakest since temporary)
Familiarize the the process of London Dispersion Forces
1.Temporary dipole appears when electrons shift within one of the nucleus
2.Adjacent molecule will be attracted to the molecule with temporary dipole and a new dipole within the second molecule will be induced
3.Electrons move back and temporary dipole disappears
4 Types of Intermolecular Forces of Attraction
→ A permanent dipole force exists between polar molecules
→Attraction form between the partially positive and partially negative ends of adjacent polar molecules
Dipole-dipole forces
Stronger than london dispersion forces since these are permanent
only polar molecules can form dipole-dipole
4 Types of Intermolecular Forces of Attraction
→ Strong dipole force exists between molecules containing** H-F, H-O or H-N** bonds (high polar due to large electronegativity difference)
Hydrogen bonding
very strong type of IMF between polar molecules
4 Types of Intermolecular Forces of Attraction
→ When an ionic compound such as NaCl dissolves in water, the water molecules arrange their oppositely charged dipole to be attracted to fully charged ion creating a very strong attractive force
Ion-Dipole Forces
