Radioactivity

Question 1

After 36 days, 8.55 grams of an original 285 gram sample remain. What is the duration of the half-life of the sample?

ROUND TO THE NEAREST WHOLE DAY.

Answer 1

7

Question 2

You start with 120 grams of an unknown radioactive sample that has a half-life of 16 hours. How much of the radioactive parent material will have decayed after three days?

RECORD YOUR FINAL ANSWER TO TWO DECIMAL PLACE

Answer 2

114.70

Question 3

100.0 grams of an isotope with a half-life of 25.0 hours is present at time zero. How many hours will have elapsed when 15.00 grams remain?

RECORD YOUR FINAL ANSWER TO TWO DECIMAL PLACES

Answer 3

68.42

Question 4

How long will it take for a 75 gram sample of Radon-222 (half-life of 3.8 days) to decay to 1/80 its original mass?

ROUND TO THE NEAREST WHOLE DAY

Answer 4

24

Question 5

At time zero, there are 1200 grams of W-187. If the half-life is 23.9 hours, how many grams will be present at the end of six days?

RECORD YOUR FINAL ANSWER TO TWO DECIMAL PLACES

Answer 5

18.43

Question 6

If Phosphorus has an atomic number of 15 and an atomic mass of 31, how many protons, neutrons, and electrons will be present, respectively:

Answer 6

15, 16, 15

Question 7

How does generation of coal energy differ from that of nuclear energy?

a) The reactions employed by the two are different, one is a chemical reaction at the level of molecules, while the other occurs at the level of the nucleus.

b) In a coal power plant water is heated, however, in a nuclear power plant, there is no need for water.

c) The waste from burning coal is radioactive and must be safely stored for thousands of years.

d) Nuclear energy production is a worse polluter of greenhouse gases, in particular CO2.

Answer 7

A

Question 8

The half-life of an unknown radioactive sample is approximately 15.8 years. How many years will it take for the sample to lose 87.5% of its radioactivity?

ROUND TO THE NEAREST WHOLE YEAR

Answer 8

47