True or False Exam 3 Flashcards
In an acidic solution at 25C, [H3O+] > 1.0 x10−7 M and pH > 7. Why?
False, it is lower than 7
A solution with a pH of 2 has a hydronium ion, H3O+, concentration that is 30 times greater than that of a
solution of pH 5. Why?
False, its 30 times less since pH 2 is less than pH 5
if the [H3O+] in an aqueous solution at 25C is less than 1.0 x 10−7 M, then the pH is greater than 7. Why?
True, because this is saying the H3O is reacting with water so then 7 so obviously the pH is greater than 7
A Bronsted acid is a hydrogen ion donor. Why?
True because its the H+ and A- so it has to give an H.
A conjugate acid/base pair differs by one H+ ion. Why?
True, because acid donates an H+ and makes its conj. base that way
When comparing acids of equal concentration, the stronger the acid, the lower the pH of the solution. Why?
False, because its equal they are of equal concentration
The weaker the acid, the lower the pH. Why?
False, weaker acid means a higher pH
For a strong acid, the [H3O+] is approximately equal to the initial concentration of the acid. Why?
True, because they are both strong acids
Compare 0.1 M H2SO3 to 0.1 M H2SO4. The pH of the H2SO3 solution is lower than the H2SO4 solution. Why?
False
In an acidic solution at 25C, pOH > 7. Why?
True, because the acidic solution means a low pH and a high pOH
A solution with pH of 1 is 1000 times more acidic than a solution with a pH of 4. Why?
False, they go by 10’s, so really 1 is 30 times less than 4
A solution with a pH of 14 is 30 times more basic than a solution with a pH of 11. Why?
True, consider them 10 to the power of the numbers, 14-11= 3 so it is 30 times more basic.
The higher the pOH of a solution, the weaker the acid (assuming equal concentrations). Why?
False, higher pOH means lower pHso stronger acid
The concentration of H3O+ for CH3COOH is approximately equal to the initial concentration of the acid. Why?
False, because the initial concentration is a weak acid
A substance with an [OH─-] equal to 1.0 X 10─8 must be acidic. Why?
True, because the pOH is 8 so the pH is around 4
When a strong acid is added to a buffer solution, the pH of the solution increases. Why?
False, Ph decreases
When F− is added to a hydrofluoric acid solution (HF), the solution’s pH decreases. Why?
False, Ph increases
A strong base reacts with a buffer solution to produce OH–. Why?
False,bases dont react with a buffer solution
When HCl is added to a buffer solution containing H2SO3 and NaHSO3 as the buffer components, the HCl will
react with the HSO3─ portion of the buffer. Why?
True, because we are trying to make H2SO3
The stronger an acid, the weaker its conjugate base. Why?
True, because strong acids make weak bases
Weak acids have conjugate bases that are weak. Why?
True, it cannot make a strong base since its already weak
All salts are composed of metals bonded to nonmetals. Why?
False, some salts have no metals. it just ionic bonded to nonionic
Strong acids have conjugate bases that are strong bases. Why?
False, the stronger the acid the weaker the base
A buffer is a solution that prevents the pH from changing when a strong acid or base is added to the solution. Why?
False, it doesnt prevent it just assists in lowering the amount of change happening.
A solution of NH3/NH4Cl would be an example of a buffer. Why?
True, its an ion bonded to a nonionic compound
The reaction of HCl with the buffer solution HClO/NaClO would be:
HClO + HCl → Cl- + H2ClO+. Why?
False, because it would react to MAKE the HClO, so HCl+ CLO- instead!
