Chapter 4: Types of Chemical Reactions and Solution Stoichiometry Flashcards
Solvent
Dissolving medium
Aqueous solution
A solution in which water is the dissolving medium or solvent
Polar molecule
A molecule that has a permanent dipole moment
Hydration
The interaction between solute particles and water molecules
Solubility
The amount of a substance that dissolves in a given volume of solvent at a given temperature
Solute
A substance dissolved in a liquid to form a solution
Electrical conductivity
The ability to conduct an electric current
Strong electrolyte
A material that, when dissolved in water, gives a solution that conducts an electric current very efficiently (completely ionized)
Weak electrolyte
A material that, when dissolved in water, gives a solution that conducts only a small electric current (produces relatively few ions)
Nonelectrolyte
A substance that, when dissolved in water, gives a nonconducting solution (produces no ions)
Classes of strong electrolytes
- Soluble salts
- Strong acids
- Strong bases
Acid
A substance that produce H+ ions (protons) when it is dissolved in water (PROTON DONOR)
Strong acid
An acid that completely dissociates to produces an H+ ion and the conjugate base (HCl, HF, HBr, HNO3, H2SO4, HClO4) (PROTON ACCEPTOR)
Strong base
A metal hydroxide salt that completely dissociates into its ions in water (LiOH, NaOH, KOH, Ca(OH)2, Sr(OH)2, Ba(OH)2)
Weak acid
An acid that dissociates only slightly in aqueous solution
Weak base
A base that reacts with water to produce hydroxide ions to only a slight extent in aqueous solution
Molarity
Moles of solute per volume of solution in liters
Standard solution
A solution whose concentration is accurately known
Dilution
The process of adding solvent to lower the concentration of solute in a solution (M1V1 = M2V2)
Three main types of solution reactions
- Precipitation reactions
- Acid-base reactions
- Oxidation-reduction reactions
Precipitation reaction
A reaction in which an insoluble substance forms and separates from the solution
Precipitate
The solid that forms from a precipitation reaction
Formula equation
An equation representing a reaction in solution showing the reactants and products in undissociated form ,whether they are strong or weak electrolytes
Complete ionic equation
An equation that shows al substances that are strong electrolytes as ions
Net ionic equation
An equation for a reaction in solution, where strong electrolytes are written as ions, showing only those components that are directly involved in the chemical change
Steps for solving stoichiometry problems for reactions in solution
- Identify the species present in the combined solution, and determine what reaction occurs
- Write the balanced net ionic equation for the reaction
- Calculate the moles of reactants
- Determine which reactant is limiting
- Calculate the moles of product or products, as required
- Convert to grams or other units, as required
Neutralization reaction
An acid-base reaction
Steps for performing calculations for acid-base reactions
- List the species present in the combined solution before any reaction occurs, and decide what reaction will occur
- Write the balanced net ionic equation for this reaction
- Calculate the moles of reactants. For reactions in solution, use the volumes of the original solutions and their molarities
- Determine the limiting reactant where appropriate
- Calculate the moles of the required reactant or product
- Convert to grams or volume (of solution), as required
Volumetric analysis
A technique for determining the amount of a certain substance by doing a titration
Titration
A technique in which one solution is used to analyze another, involving delivery (from a buret) of a measured volume of a solution of known concentration (the titrant) into a solution containing the substance being analyzed (the analyte)
Equivalence point/stoichiometric point
The point in the titration where enought titrant has been added to react exactly with the analyte
Indicator
A substance added at the beginning of the titration that changes color at (or very near) the equivalence point
Endpoint
The point where the indicator actually changes color =
Oxidation-reduction reactions
Reactions in which one or more electrons are transferred
Oxidation states
A concept that provides a way to keep track of electrons in oxidation-reduction reactions according to certain rules
Oxidation
An increase in oxidation state (a loss of electrons)
Reduction
A decrease in oxidation state (a gain of electrons)
Oxidizing agent
Electron acceptor
Reducing agent
Electron donor
Steps for balancing oxidation-reduction reactions by oxidation states
- Write the unbalanced equation
- Determine the oxidation states of all atoms in the reactants and products
- Show electrons gained and lost using “tie lines.”
- Use coefficients to equalize the electrons gained and lost
- Balance the rest of the equation by inspection
- Add appropriate states
