CSES 2040: Exam 2 UPDATED Questions
and CORRECT Answers
All soils have negative and positive charge sites - CORRECT ANSWER - true
MOST soils have an overwhelmingly negative charge - CORRECT ANSWER - true
Anion exchange capacity - CORRECT ANSWER - attraction of negatively charged ions
Cation exchange capacity - CORRECT ANSWER - degree to which a soil has negative
charges
cations - CORRECT ANSWER - positively charged ions
anions - CORRECT ANSWER - negatively charged ions
+3 charge - CORRECT ANSWER - Al>, 0.48 hydrated radius (nm), 27 weight (grams)
+ - CORRECT ANSWER - H>, 0.10 hydrated radius (nm), 1 weight (grams)
+2 - CORRECT ANSWER - Ca>, 0.96 hydrated radius (nm), 40 weight (grams)
+2 - CORRECT ANSWER - Mg>, 1.08 hydrated radius (nm), 24 weight (grams)
1) + - CORRECT ANSWER - K=, 0.53 hydrated radius (nm), 39 weight (grams)
2) + - CORRECT ANSWER - NH4>, 0.54 hydrated radius (nm), 18 weight (grams)
, 3) + - CORRECT ANSWER - Na>, 0.79 hydrated radius (nm), 23 weight (grams)
CEC - CORRECT ANSWER - measure of exchangeable sites
why do we overestimate CEC in acid soils? - CORRECT ANSWER - we add NH4-
acetate at a pH of 7, which creates more negative sites
the solution to this... - CORRECT ANSWER - calculate the Effective CEC
ECEC - CORRECT ANSWER - Ca + Mg + K + Na + Al + H
Typical C.E.C. range - CORRECT ANSWER - 1-30 Mg
nonacid cations (don't change acidity) - CORRECT ANSWER - Ca2+, Mg2+, Na+, K+
% base saturation - CORRECT ANSWER - = (nonacid cations/CEC(nonacid + acid))x100
acid cations - CORRECT ANSWER - H+ and Al3+
base saturation - CORRECT ANSWER - should not be used for fertilizer recomendations
lower saturation - CORRECT ANSWER - in highly weathered SE soils
H+ - CORRECT ANSWER - only acidic cation
high AEC - CORRECT ANSWER - holds onto phosphorous
and CORRECT Answers
All soils have negative and positive charge sites - CORRECT ANSWER - true
MOST soils have an overwhelmingly negative charge - CORRECT ANSWER - true
Anion exchange capacity - CORRECT ANSWER - attraction of negatively charged ions
Cation exchange capacity - CORRECT ANSWER - degree to which a soil has negative
charges
cations - CORRECT ANSWER - positively charged ions
anions - CORRECT ANSWER - negatively charged ions
+3 charge - CORRECT ANSWER - Al>, 0.48 hydrated radius (nm), 27 weight (grams)
+ - CORRECT ANSWER - H>, 0.10 hydrated radius (nm), 1 weight (grams)
+2 - CORRECT ANSWER - Ca>, 0.96 hydrated radius (nm), 40 weight (grams)
+2 - CORRECT ANSWER - Mg>, 1.08 hydrated radius (nm), 24 weight (grams)
1) + - CORRECT ANSWER - K=, 0.53 hydrated radius (nm), 39 weight (grams)
2) + - CORRECT ANSWER - NH4>, 0.54 hydrated radius (nm), 18 weight (grams)
, 3) + - CORRECT ANSWER - Na>, 0.79 hydrated radius (nm), 23 weight (grams)
CEC - CORRECT ANSWER - measure of exchangeable sites
why do we overestimate CEC in acid soils? - CORRECT ANSWER - we add NH4-
acetate at a pH of 7, which creates more negative sites
the solution to this... - CORRECT ANSWER - calculate the Effective CEC
ECEC - CORRECT ANSWER - Ca + Mg + K + Na + Al + H
Typical C.E.C. range - CORRECT ANSWER - 1-30 Mg
nonacid cations (don't change acidity) - CORRECT ANSWER - Ca2+, Mg2+, Na+, K+
% base saturation - CORRECT ANSWER - = (nonacid cations/CEC(nonacid + acid))x100
acid cations - CORRECT ANSWER - H+ and Al3+
base saturation - CORRECT ANSWER - should not be used for fertilizer recomendations
lower saturation - CORRECT ANSWER - in highly weathered SE soils
H+ - CORRECT ANSWER - only acidic cation
high AEC - CORRECT ANSWER - holds onto phosphorous
