NAME:____________________________________
CEE 311
QUIZ # 3
1.Two pollutants were tested for biodegradability. Data analyses indicated the following
trends:
Pollutant A
Pollutant B
C
ln C
Time (hours)
Time (hours)
What is the reaction order for the biodegradation of pollutant A? ZERO
What is the reaction order for the biodegradation of pollutant B? FIRST
2. The USA conducted numerous nuclear tests in the Marshall Islands in the 1940-1950s. The concentration
of radioactive cesium (137Cs) in the island air in 1946 was determined to be 120,000 Bq/L (Bq=Bequerel a
measure of radioactivity). The half life of
137
Cs is known to be 30 years. The acceptable levels of cesium for
-7
human exposure is 1.3x10 Bq/L. How long (in years) will it take for the 137Cs levels in the Marshall Islands to
reach acceptable levels?
30 = ln2/k or k = 0.0231 yr-1
ln
1.3x10-7 = -0.0231 yr-1 * t or t
120,000
= 1,192.683 years
3. What is the reaction rate in min-1 for a first order reaction if 99.999% of bacteria need to be
removed by disinfection in 10 minutes?
ln (100-99.999) = -k*10 or k = 1.15 min-1
100
BONUS
The intake of Shushi by a freshman student is directly proportional to the number of sushi
available. If the initial number of Sushi is 200 pieces/platter and the rate at which the student
eats sushi is 0.001/second how many sushi pieces will be left after 5 minutes?
C = e-0.001*5*60 = 148.16 pieces
200
Student has eaten 51 and almost one more