DAY 1

Question 1

Milk samples from a dairy farm in Bohol were collected as per ordered by the Department of Agriculture. The milk was determined to contain K-40. The cow’s milk has a specific activity of about 6x10^-11 mCi per milliliter. How many disintegrations of K-40 are there per minute in 1.0 qt of milk?
A: 109.0 disintegrations per minute
B: 126.0 disintegrations per minute
C: 144.0 disintegrations per minute
D: 173.0 disintegrations per minute

Answer 1

B

Question 2

“Ako ay may lobo” height? …

Answer 2

127 m

Question 3

A brain scan procedure performed at St. Lukes Medical Center involves injecting 20 mCi of metastable Technetium-99 on a patient. Tc-99m decays by gamma radiation and has a half-life of 6.0 hours. The energy of a gamma photon is 2.29x10^-14 J. The RBE of these photons is 0.98 and only two-thirds of the photons are absorbed by the body. Assuming all of the Tc- 99m nuclei decay inside the patients body, What is the rem dose received by a 70 kg patient.
A: 0.49 rem B: 0.62 rem
C: 0.78 rem D: 0.91 rem

Answer 3

A

Question 4

Six small bone and eight teeth samples of Homo luzonensis was obtained in Callao Cave at Penablanca, Cagayan. The carbon obtained from one of the teeth samples gave 0.008 disintegrations of Carbon-14 per minute per gram of Carbon. How old is the Homo luzonensis from Callao Cave?
A: Between 50,000 to 55,000 years old
B: Between 55,000 to 60,000 years old
C: Between 60,000 to 65,000 years old
D: Between 65,000 to 70,000 years old

Answer 4

C

Question 5

(Typo) A piece of Calcium metal is shined with a light of wavelength 345 nm. The photoelectric work function of calcium is 4.34x10-19 J. What is the speed of the ejected electron?
A: 2.25x10^5 m/s B: 4.05x10^5 m/s
C: 5.70x10^5 m/s D: 6.55x10^5 m/s

Answer 5

A

Question 6

A traveler is exploring various locations in the Philippines. During one of her journeys, she realized that she forgot to boil the eggs beforehand. She knows that the average time to boil an egg, under 1 bar, is 3 minutes. If she can boil all of the eggs at the same time, where should she boil the eggs if she can only stop in each location for no more than 3 minutes?

Answer 6

Jaro, Iloilo

Question 7

What is the empirical formula of the Human DNA?

Answer 7

C39H50O22N15P3

Question 8

1 drop of water

Answer 8

Molecules=1.7x10^-21
ML or g =0.05

Question 9

A farmer has a 7-year rotation of corn, soybeans, and wheat and 4 years of alfalfa. Manure will be applied before corn and wheat and before sceding to alfalfa. The initial soil test results indicate total phosphorus level of 48 kg P. hectare-. Manure is to be surface-applied in mid-March and disk-incorporated within 2 days of application. One-third of the organic nitrogen and 50%6 of the nitrogen from NH; is available to the corn crop. To obtain the desired yield of corn, the local
extension agent has told the farmer to apply 100 kg of nitrogen per hectare

Answer 9

P = 77 kg/ha
K = 48 kg/ha

Question 10

An environmental engineering Student was very interested in the reaction of the chemical 2,4,0-chickenwire. She went into the lab and found that 2,4,6-chickenwire degrades in water.

Answer 10

First order

Question 11

A power plant in a college town is burning coal on a cold, clear winter morning at 8:00 A.M. with a wind speed of 2.6 m-s-‘ measured at 30 m elevation and an inversion layer with its base at a height of 697 m. The effective stack height is 30 m. Calculate the distance downwind XL at which the plume released will reach the inversion layer and begin to mix downward.

Answer 11

5.8 km

Question 12

A chemical engineering professor recorded her household waste generation as shown below. If a container volume is 0.076 cubic
meter, what is the average density of the solid wäste produced the household. Each empty container has a mass of 3.61 kilograms (table)

Answer 12

58 kg/cu m

Question 13

We heat 50.0 g of an unknown substance by adding 205 cal, and its temperature rises by 7.0°C. Identify the substance.
A. water
C. benzene
B. ethanol
D. acetic acid

Answer 13

Ethanol

Question 14

A certain volume of a
KMnO4 will oxidize sufficient potassium tetraoxalate that requires half of that volume using 0.201N of KOH solution for neutralization. Determine the quantity of KMnO4 in a liter solution.

Answer 14

2.01 g/L or 2.44 g/L

Question 15

Analyze and calculate the percentage of nickel in a 1.201g sample of nickel ore which was analyzed by the volumetric method. A solution of 48mL containing 1.4x10-2g of KCN/mL and the excess cyanide required half a milliliter of silver nitrate solution with 1.25x10-2g AgNO3 per milliliter.
a. 9.36% b. 15.21% c. 12.5% d. 8.22%

Answer 15

C

Question 16

If the normality of HCl is greater by 10% compared to KOH, estimate the normality of the HCl solution when 0.67g of (NH4)2SO4 is dissolved in water, treated with excess NaOH and the ammonia released is passed through a solution of 20mL of HCl. The excess acid solution is titrated using 15.01mL of KOH solution.

Answer 16

0.152 N

Question 17

A town of 20,000 in Germany generates 0.95 kg/(capita)-day of MSW. A town of the same size in the United States generates 1.9 kg/(capita)-day of MSW.

How much MSW is generated in each town?

Answer 17

Germany – 20000, US – 40000

Question 18

How many trucks would be needed to collect the waste twice weekly? The trucks each have a capacity of 4.5 MT and operate 5 days per week. Assume that the trucks average two loads per day at 75% capacity.

Answer 18

Germany – 4, US – 8

Question 19

A city of 200,000 people disposes of 1.05 m3/s of treated sewage that still has a BODu of 28.0 mg/L and 1.8 mg/L of DO into a river. Upstream from the outfall, the river has a flowrate of 7.08 m3/s and a velocity of 0.37 m/s. At this point, the BODu and DO in the river are 3.6 and 7.6 mg mg/L, respectively. The saturation value of DO (at the temperature of the river) is 8.5 mg/L. The deoxygenation coefficient, kd, is 0.61 day−1, and the reaeration coefficient, kr, is 0.76 day−1. Assume complete mixing and that the velocity in the river is the same upstream and downstream of the outfall.

What is the oxygen deficit just downstream from the outfall (just after mixing, before any reaction can occur)?

Answer 19

1.6 mg/L

Question 20

Calculate the critical distance.

Answer 20

34 km

Question 21

Calculate the minimum DO.

Answer 21

5.7

Question 22

Just below the point where a continuous discharge of pollution mixes with a river, the BODu is 10.9 mg/L, and DO is 7.6 mg/L. The river and waste mixture has a temperature of 20°C, a deoxygenation constant kd of 0.20/day, an average flow speed of 0.30 m/s, and an average depth of 3.0 m.

Find the distance downstream at which the oxygen deficit is at a maximum. The saturation value of DO at 20°C is 9.1 mg/L
a. 43 miles c. 66 miles
b. 35 miles d. 58 miles

Find the minimum value of DO.
a. 5.5 mg/L c. 6.0 mg/L b. 5.8 mg/L d. 6.7 mg/L

Answer 22

43 miles, 6mg/L

Question 23

Given the same power plant and conditions as were found in Example 12-3, determine the concentration of SO, at a point 4 km downwind and 0.2 km perpendicular to the plume centerline (y = 0.2 km) if there is an
inversion with a base height of 328 m.

Answer 23

1.16 x 10-3 g - m-3

Question 24

The Nairyosangha landfll located in Peshdadians serves a population of 562,400 people generating MSW
at a rate of 1.89 kg • capita-1 - day. The volume of the landfill is 11,240,000 m?. At the present time, 63% of
the landfill is used. The ratio of cover to compacted fill is 1.9. Determine projected life remaining for the
landfill. Assume the density of the compacted waste to be 490 kg - m=3

Answer 24

2.76 years