Chapter 7, 8, 9 - Chemistry
Show the strength of IMFs from highest to lowest
1)Ionic - Strongest 2)Hydrogen Bonds 3)Dipole-Dipole Interactions - molecules with polar covalent bonds 4)London Dispersion Forces - non polar molecules form very weak IMFs from a temporary dipole
Titration Steps
1)Using the molarity and volume of titrant added, determine the moles. 2)Use the molar ratio of the neutralization reaction to determine the moles of unknown originally in solution. 3)Divide by the original volume (in liters) to determine the original concentration
Other IMFs: Dipole-Dipole
All other molecules with polar covalent bonds form dipole-dipole interactions.
Mass/Volume Percent (m/v)
Also common in clinical settings. Describes the mass of a solute in 100 mL of the solution. m/v percent = g of solute/mL of solution X 100%
How do you assess the strength of an acid or a base?
By how much H₃O⁺ or OH⁻ it produces, respectively. Strong acids and bases dissociate completely in water, making them strong electrolytes.
What is a Solution?
Composed of two parts: a solute and a solvent
What are the different ways that you can separate solvents?
Settling, a filter, or semipermable membrane
Buffers never contain
Strong acids or strong bases
Are Ionic Solutes dissolved in water a strong, weak or non electrolyte? Why?
Strong electrolyte, because they disassociate completely in water to form ions that conduct electricity.
Can C₂H₅OH, which is ethanol dissolve in water?
The C-H bonds in ethanol are nonpolar, but the O-H bond in ethanol is polar and dissolves in water.
What is Solubility?
The maximum amount of solute that can dissolve in a given quantity of solvent.
Mass Percent (m/m)
The most common unit of concentration in clinical settings. Mass percent = g of solute/g of solution X 100%
Molarity
The most common unit of concentration used by chemists. Molarity (M) = moles (m) of solute/Liters of solution
What is a Solvent?
The substance present in greater amount.
What is a Solute?
The substance present in lesser amount.
What is unique about Carboxylic Acids?
Their H⁺ is located at the end of the molecule, such as Propanoic Acid C₂H₅COOH
What is a Dissolution Reaction?
When ionic solutes dissolve in a solvent, they separate into their corresponding ions.
What is an Aqueous Solution?
a Homogenous Mixture, the solute particles cannot be seen within the mixture, solute completely dissolves.
What is a strong electrolyte?
a strong acid or strong base compound that dissociate completely in water to form ions that conduct electricity.
What is Amphoteric?
a substance that can act as either an acid or a base. Water is an example of this.
What is a weak electrolyte?
a weak acid or a weak base compound that dissociate partially in water to form ions that conduct electricity weakly.
Hydrogen Bonds
are a special kind of intermolecular force (IMF) that occurs between molecules that contain H-F, H-O, or H-N bonds - responsible for holding liquids and solids together in a defined shape and/or volume.
What is a Hypertonic Solution?
comparing two solutions, it is the solution having the highest concentration of solute.
What is a Dipole?
created from a polar bond where one end of the bond is partially negative and the other end is partially positive.
What is Arrhenius Definition of Acids?
donates H⁺ ion, proton, in solution
What can Nitrogen-Containing Bases Do?
extract protons from other molecules, due to the lone pair of electrons on the nitrogen.
What is Arrhenius Definition of Bases?
ionic compounds that dissociates to give OH⁻ (hydroxide) ions in solution. Most Arrehnius bases are hydroxide salts with Group 1A or Group 2A metals
What happens when you dissolve an Ionic Compound in Water?
it results in it separating into corresponding ions.
Polar solvents can dissolve ________/________ solutes
polar, ionic, which explains why salts are soluble in water.
What is Osmotic Pressure?
pressure exerted by the higher compartment. At some point, the pressure will be high enough that no more water can flow into the compartment.
What are electrolytes?
substances such as salts and acids, that dissociate in water to form ions that conduct electricity.
What is a Concentration?
the amount of solute in a solution. Concentration = amount of solute/amount of solution
Nonpolar Solvents, such as hexane and benzene are nonpolar because?
they contain only C-H bonds, which can dissolve nonpolar solutes.
What is an Isotonic Solution?
when comparing both solutions, the same concentration of solutes are present in both.
What is a Hypotonic Solution?
when comparing two solutions, it is the one having the lower concentration of solute.
Calculating [H3O+] from pH
***pH = - log [H3O+] ***To find the [H3O+] from the pH, use the inverse log function ***[H3O+] = 10^⁻pH
What does pH mean?
**pH is a measure of the [H3O+] **pH = - log [H3O+] ***Remember: brackets refer to the molar concentration of H3O+ (moles/L) ****Something that has a high [H3O+] has a low pH and vice versa
Weak bases are generally what?
Nitrogen containing bases.
What is a Colloid?
A solution and homogeneous mixture where the solute particles are large - can be proteins or large molecules such as Milk.
Reactions: Neutralizations
A strong acid and a strong base will "neutralize" each other to produce water and a salt. Example: HBr (aq) + KOH (aq) → H2O (l) + KBr (aq)
Acetic Acid Buffer
Acetic acid is a weak acid and only dissociates partially in water HC2H3O2 + H2O ←→ C2H3O2- + H3O+
Reactions: Acids with Carbonates
Acid + Carbonate → CO2 (g) + H2O + Salt Example: HCl + NaHCO3 → CO2 + H2O + NaCl
Reactions: Acid + Metal
Acid + Metal → Salt + H2 (g) Example: 2HCl (aq) + Mg (s) → MgCl2 (aq) + H2 (g) *Metals that react with acids include potassium, sodium, calcium, magnesium, aluminum, zinc, iron and tin
What happens when you add a base to water?
Adding a base causes the OH⁻ ions to increase making the solution more basic.
What happens when you add an acid to water?
Adding acid causes the H₃O⁺ ions to increase making the solution more acidic
What is Henry's Law?
Gases are soluble in aqueous solution. If a gas has a higher pressure, it will have a higher solubility. Gasses are more soluble at lower temperatures in aqueous solution.
What are Suspensions?
Heterogeneous and nonuniform mixtures. Particles can be seen with the naked eye and often settle to the bottom. Examples: Oil and Vinegar, Orange Juice
What are the 6 Common Strong Acids?
HydroIodic Acid - HI HydroBromic Acid - HBr Perchloric Acid - HClO₄ Hydrochloric Acid - HCl Sulfuric Acid - H₂SO₄ Nitric Acid - HNO₃
What is the Hydronium Ion
H₃O⁺, which is an acid formed with a H⁺ ion forms with water. The presence of H₃O⁺ is what makes a solution acidic.
Do Nonelectrolytes conduct electricity?
No, because they don't form ions.
What happens when a base reacts with water?
It produces a hydroxide ion
Autoionization of Water at 25°C
Kw = [H₃O⁺] + [OH⁻]= 1.0 X 10⁻⁷ M
Solubility
Like Dissolves Like
Are Covalent Compounds dissolved in water a strong, weak or non electrolyte? Why?
Non electrolyte, because they do not dissociate. A molecule such as sugar C₆H₁₂O₆ contains O-H bonds, which make it soluble in water but since it is covalent it will not form any ions.
London Dispersion Forces
Nonpolar molecules have very weak IMFs, sometimes a temporary dipole can exist because atoms vibrate in molecules.
What kind of molecule is Water?
Polar molecule because it has lone pairs of electrons on its central oxygen atom, which results in a net dipole.
What is the Bronsted-Lowry Definition of Bases?
Proton accceptors, not all bases dissociate to form OH⁻ ions
What is the Bronsted-Lowry Definition of Acids?
Proton donors
When a solute added to a solution exceeds its solubility it is said to be?
Saturated
Acid-Base Titrations
Titrations use neutralization reactions to determine the concentration of an unknown acid or base Example: HCl (aq) + NaOH (aq) → H2O + NaCl (aq) *If we know the moles of NaOH that we have to add to neutralize the acid, we can calculate the moles of HCl originally in the unknown solution!
When a solute added to a solution has not exceeded its solubility it is said to be?
Unsaturated
What does the pH scale range from?
Used to quantify the strength of acids and bases. Ranges from 0-14: pH 0-7: Acidic Solution (more H3O+ than OH-) pH 7: Neutral Solution (equal amounts of H3O+ and OH-) pH 7-14: Basic Solution (more OH- than H3O+)
Volume Percent (v/v)
Volumes of liquids and gases are easily measured - volume units must be identical. Volume percent = Vol of solute/Vol of solution X 100%
Why does Water have such a high boiling point?
Water can form hydrogen bonds with itself, while other molecules cannot.
Buffers consist of a?
Weak acid and its conjugate base or visa versa. The acids and bases cannot neutralize each other!
Why do weak electrolytes conduct electricity?
Weak electrolytes are a mixture of molecules with partially dissociated ions. The ions that are formed conduct electricity.