Chapter 04: Chemical Quantities and Aqueous Reactions Flashcards
Stoichiometry
Quantitative relationships between products and reactants in chemical equations
Requires use of:
1) Balanced chemical equation
2) Conversion factor: mole ratios
Mole ratio
Ratio in units of moles relating any two species in a chemical reaction
Used as a conversion factor
Solving stoichoimetry problems
Mass (g) of compound A
to
Moles of compound A
using molar mass
Then to
Moles of compound B
using mole ratio
Then to
mass (g) of compound B
using molar mass
Limiting reactant (reagent)
Reactant that limits the amount of product that can be made
Excess reactant
Leftover reactant (not reacted) in a chemical reaction
Reaction yield: theoretical yield
The amount of product that would result if all the limiting reactant reacted
Reaction yield: actual yield
The amount of product that is actually obtained from a reaction
% yield
% yield = actual yield x 100
theoretical yield
Solution
Homogenous mixture of 2+ substances
Solvent
Substance present in larger amount within solution
Solute
Substance(s) present with smaller amounts dissolved in solvent
Aqueous solution
Solution with water as solvent
Solution concentration
Qualitative and/or quantitative description of amount of solute in a solvent/solution
Molarity
Molarity (M) = moles of solute (n)
liters of solution (V)
Dilute solution
Relatively small amount of dissolved solute
Concentrated solution
Relatively large amount of dissolved solute
Dilution
Procedure for preparing a less concentrated solution from a more concentrated solution
Dilution formula
M1V1=M2V2
Where M = molarity
V = volume
*moles (n) of solute remain the same
Solute and solvent interactions
Attractive forces between solute particles, between solvent particles, and between solute and solvent particles
If attractions between solute and solvent are strong enough –> dissolve
Charge distribution in water molecule
Oxygen = partial charge negative Hydrogen = partial charge positive
Hydration
Process in which an ion is surrounded by water molecules arranged in a specific manner
Electrolyte
Substance that, when dissolved in water, conducts electricity
Contain cations and anions –> dissolve into ions
(Ionic compounds, some acids, some bases)
Nonelectrolyte
Substance that, when dissolved in water, does not conduct electricity
No cations, no anions
(Molecular substances)
Strong electrolyte
Dissolve completely as ions
*Irreversible reaction.
Most salts, some acids and bases
Weak electrolyte
Do not dissolve completely as ions
*Reversible reaction
Dissociation
Ions of a salt separate as salt dissolves
Ionization
Process of ion formation in solution
Results from chemical reaction between water + compound
(acids, bases)