Quiz on unit 8 must knows

#1 Which of the following definitions matches the term?

pH + pOH =

14 always!! within 1 pH of its pKa, up or down pH = pKa HA(aq) + OH- --> A-(aq) + H2O(L) if weak acid is in excess --> a buffer --> Hendeson Hasselbalch equaiton if strong base is in excess, the moles of excess hydroxide ions is used for pH if acid and base are equimolar then the equilibrium concentr

#2 Which of the following terms matches the definition?

if weak base is in excess --> a buffer --> Hendeson Hasselbalch equaiton if strong acid is in excess, the moles of excess acid are used to determine pH if acid and base are equimolar then the equilibrium concentrations are used to determine pH

pH + pOH = strong acid-weak base reaction how to increase/decrease buffering capacity strong acid-weak base reaction

#3 Which of the following terms matches the definition?

increasing/decreasing concentrations of buffer components, but keeping the ratios constant (if you don't it'll change the buffer capacity for either acid or base respectively)

how to increase/decrease buffering capacity strong acid-weak base reaction maximum buffering capacity strong acid strong base equivalence point

#4 Which of the following definitions matches the term?

weak acid-strong base reaction

solution that is resistant to a small pH change, it has to contain a weak acid or base pared with its conjugate salt(Na+, H3O-, etc...) and it creates neutral compounds, keeping pH relatively stable HA(aq) + OH- --> A-(aq) + H2O(L) if weak acid is in excess --> a buffer --> Hendeson Hasselbalch equaiton if strong base is in excess, the moles of excess hydroxide ions is used for pH if acid and base are equimolar then the equilibrium concentr within 1 pH of its pKa, up or down pH = pKa

#5 Which of the following terms matches the definition?

True

False

Section 1: Multiple Choice questions

pH + pOH =

if weak base is in excess --> a buffer --> Hendeson Hasselbalch equaiton if strong acid is in excess, the moles of excess acid are used to determine pH if acid and base are equimolar then the equilibrium concentrations are used to determine pH

increasing/decreasing concentrations of buffer components, but keeping the ratios constant (if you don't it'll change the buffer capacity for either acid or base respectively)

weak acid-strong base reaction

pH = pKa

Section 2: True/false questions

strong acid strong base equivalence point

pH = 7 @ 25 C / 298 K

how do you calculate a buffer's pH

pH = pKa + log [A-]/[HA] ---> acids pOH = pKb + log [BH+]/[B] ---> bases the conjugate salt is on top, and the bottom is either the base or the acid assume there is a limiting and excess reagent (because it will contain either a strong acid or base)

in what range are buffers effective

if weak base is in excess --> a buffer --> Hendeson Hasselbalch equaiton if strong acid is in excess, the moles of excess acid are used to determine pH if acid and base are equimolar then the equilibrium concentrations are used to determine pH

what is a buffer

pH = pKa

H2O pH is always...

7, could be acid (pH) or base (pOH)

Triple-checked your answers?

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