Things to Know for the Acids, Bases, Salts and pH Test
How do solutions form? Do energy transformations take place? - One substance must dissolve in
another to form a solution. Yes, energy can be released or absorbed during the production of a solution.
When an ionic compound dissociates in water, the cations are attracted to the negative end of the polar
water molecule while the anions are attracted to the positive end of the polar water molecule.
What things can increase the rate at which a substance dissolves? - Increasing the surface area by
breaking the substance into smaller pieces, increasing the temperature of the solvent, or agitation can
increase the dissolving rate of a substance. Increasing the number of collisions between solute particles
and solvent particles increases the rate of dissolving.
Know your properties of acids and examples of common acidic substances. For example, citrus fruit and
tomatoes are slightly acidic. Acid properties include tasting sour, produce hydrogen, will react with
metals, change colors of indicators, are proton donors, litmus turns red, etc.
Know your properties of bases and examples of common bases. Ammonia (ammonia accepts a proton
to become ammonium, NH4+) and soaps are bases. Bases feel slippery, taste bitter, are corrosive, and
change the colors of indicators, are proton acceptors, litmus turns blue, etc.
Knowing that a salt and water are always the products of a neutralization reaction, what are the
products of a neutralization reaction between hydrochloric acid and magnesium hydroxide?
Know your vocabulary!!!
Know the pH scale. pH is a measure of hydrogen ion or hydronium ion in solution. Water is neutral at a
pH of 7. Weak acids have a pH of 7 to 3 and strong acids have a pH lower than 3. Strong bases have a
pH above 10. Weak bases have a pH between 7 and 10.
Strong bases dissociate completely. Strong acids ionize and then dissociate completely. (Dissociate
means to break into ions.) Both strong acids and strong bases make strong electrolytes. Weak acids and
bases will only dissociate slightly and will not harm you if you eat them in foods.
When buffers are added to a solution the solution will RESIST pH changes when additional acid or base is
added.
Physical properties of freezing point, boiling point and conductivity differ in solutions and solutes.
Example: A solute will have a different boiling point than a solution that contains that solute.
Acid solutions form by ionization. Bases form by dissociation.
How do you make a supersaturated solution? – Heat the solvent and dissolve more solute. Allow the
solution to cool.