Honors Chemistry Study Guide: Solutions, Acids, and Bases

solution

solution

a homogenous mixture of two or more substances in one state of matter

• particles evenly distributed

• substances don’t separate

• “one substance dissolved in another”

Solutions can be dissolved in…

• kool-aid (gasses dissolved in gasses)

• Air (gasses dissolved in gasses)

• Ponds (gasses dissolved in liquids)

• Gasoline (liquids dissolved in liquids)

• Alloys (solids dissolved in solids

solute

the substance that is dissolved

solvent

the substance that does the dissolving (more abundant)

solution =

solute + solvent

aqueous solution

any solution where water is the solvent

molarity (M)

concentration of a solution; measured in the number of moles of solute dissolved in ever liter of solution

molality (m)

concentration of a solution; measured in moles of solute dissolved in each kilogram of solvent

molarity equation

M = moles of solute/liters of solution

molality equation

m = moles of solute/kg of solvent

M =

n solute/ V

equation for # of moles of solute

n solute = MV

2.80 M NaCl (aq)

• 2.80 = solution concentration

• M = mol solute/ L solution

• NaCl = solute

• (aq) = solvent (water)

steps to prepare a solution

1. Calculate amount of solute needed

2. Measure solute

3. Fill volumetric flask half with distilled water

4. Add solute

5. Swirl mixture to dissolve solute

6. Add distilled water up to line

7. Label solution

Why do some things dissolve?

• Solvent particles are strongly attached to solute particles

• Solute particles are pulled away from other solute particles

• Solute particles surrounded by solvent particles, creating homogenous mixture

saturated solution

when a solution reaches a point where it can’t dissolve anymore solute (maximum concentration)

solubility

)measure of the maximum amount of solute that can be dissolved in a solvent (under given conditions

solubility depends on…

1. solute-solvent attraction

2. temperature

3. pressure

supersaturated solution

a solution that contains more solute than the solvent would normally dissolve under current conditions

solutions in everyday life

kool-aid, seawater, tea, gatorade, antifreeze

acids in everyday life

• acetic acid (vinegar)

• carbonic acid (pop)

• citric acid (citrus fruit)

bases in everyday life

• hydroxide (deodorant)

• bicarbonate (baking soda)

• hypochlorite (bleach)

H+

hydrogen ion (proton)

Bronsted-Lowry definitions

acid = a substance that can donate H+ ions in a solution

base= a substance that can accept H+ ions in a solution

properties of acids

• sour taste

• conduct electricity

• corrosive

• react with some metals to make hydrogen (g)

• react with carbonates to make CO2 (g)

properties of bases

• bitter taste

• conduct electricity

• corrosive

conjugate base

formed when an acid loses a H+

conjugate acid

formed when a base gains a H+

indicators

chemicals that change color depending on the pH of the solution (phenolphthalein = more pink when basic, clear when acidic, light pink when neutral)

pH

a measure of the strength of an acid or base (really a measure of the concentration of H+ in a solution)

pH equation

pH = -log[H+] (H+ = molarity of hydrogen ions)

strong acids

acids that completely dissociate in water

• 100% of molecules break apart to form ions

• Produce many H+ (lower pH)

weak acids

acids that DO NOT dissociate in water

• less than 100% of molecules form ions in water

• Produce very few H+ (higher pH)

strong bases

substances that have a strong attraction for H+ in solution

weak bases

substances that have a weak attraction for H+ in solution

neutralization reaction

when an acid and a base react in proper amounts to neutralize each other

titration

a carefully controlled reaction where an unknown solution is reacted with a known solution

standard solution

a solution with a known concentration

equivalence point

the stopping point in an acid-base titration when a neutralization reaction occurs

alloy

homogenous mixture of metals

alloys used in everyday life

• steel (scissors, keys, appliances)

• bronze (coins, doorknobs)

• brass (watches, instruments)

Ma x Va = Mb x Vb

molarity of acid x volume of acid = molarity of base x volume of base (at equivalence point)