Quiz on unit 8 must knows

#1 Which of the following definitions matches the term?

pH + pOH =

1.0 x 10^-14 at 25 C or 298 K pH = 7 @ 25 C / 298 K 14 always!! 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

#2 Which of the following definitions matches the term?

strong acid-weak base reaction

within 1 pH of its pKa, up or down 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) 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 = 7 @ 25 C / 298 K

#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 do you calculate a buffer's pH how to increase/decrease buffering capacity maximum buffering capacity how to increase/decrease buffering capacity

#4 Which of the following definitions matches the term?

weak acid-strong base reaction

1.0 x 10^-14 at 25 C or 298 K 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 pH = pKa 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

#5 Which of the following definitions matches the term?

True

False

Section 1: Multiple Choice questions

pH + pOH =

strong acid-weak base reaction

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

maximum buffering capacity

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

1.0 x 10^-14 at 25 C or 298 K

in what range are buffers effective

within 1 pH of its pKa, up or down

what is a buffer

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

H2O pH is always...

straight line up part of graph #miles of titrant = #moles of analyte concentration and volume of titrant is then used to determine concentration of analyte

Triple-checked your answers?

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