Chapter 5 Pre-Lecture HW

Phosphorus-32 has a half-life of 14.0 days. Starting with 6.00 g of 32P, how many grams will remain after 70.0 days ?

0.188 g

A wooden object from a prehistoric site has a carbon-14 activity of 10 counts per minute (cpm) compared to 40 cpm for new wood. If carbon-14 has a half-life of 5730 years, what is the age of the wood?

11,500 years

Iodine-123, which is used for diagnostic imaging in the thyroid, has a half-life of 13 hours. If 50.0 mg of I-123 were prepared at 8:00 AM on Monday, how many mg remain at 10:00 AM on the following day?

12.5 mg

At a distance of 40 ft , an ionizing radiation source delivers 5.5 rem of radiation. How close could you get to the source and still have no biological effects?

19 ft

Which of the following nuclei are likely to release energy when undergoing nuclear fusion?

2/1H deuterium

Which of the following nuclei could be used in a nuclear fission power plant?

235/92U (uranium-235) ------------------------------------------------- Uranium-235 is one of the best fissionable isotopes. Other isotopes of uranium do not undergo fission in the same way!

The half-life of carbon-14 is 5730 years. Therefore, 5730 years after being cut from a tree, a piece of wood will have 50.0% of the carbon-14 that it had originally. What percentage of the original carbon-14 will remain in the wood after another 5730 years?

25.00%

Carbon-14 has a half-life of 5730 years. In a plant fossil, you find that the 14C has decayed to 1/32.0 of the original amount. How long ago was this plant alive?

28,650 years -------------------- 2.87×10^4 years * Carbon-14 was first used in the late 1940s for dating ancient artifacts and organisms. Significant Figures Feedback: Your answer 28650 years was either rounded differently or used a different number of significant figures than required for this part.

Krypton-79 has a half-life of 35 hours. How many half-lives have passed after 105 hours?

3 half lives

Iron-59 has a half-life of 44 days. Assume you started with 24 mg of iron-59 and 132 days, which is equivalent to 3 half-lives, has passed. How much iron-59 remains?

3 mg

How old is a piece of wood that has 0.7813% of the carbon-14 of a living organism?

40,110 years

A nurse administered 3.90 mL of a radioisotope solution that has an activity of 185 μCi/mL . What total dose of the radioisotope did the patient receive?

721.5 μCi / or if rounded properly / 722 μCi

Which of the following is equivalent to an alpha particle? a. a helium nucleus b. an electron c. a high-energy light particle d. a positively charged electron

A. a helium nucleus

What symbol for the radioactive particle is missing for the letter "A" in the following nuclear decay reaction? 133 54 Xe → 133 55 Cs + A A. gamma particle B. positron particle C. beta particle D. alpha particle

C. beta particle

Fluorine-18 is a positron emitter used in PET scans. Write a balanced nuclear equation for the reaction. A. 189 F + 0+1 e → 188 O B. 189 F → 0+1 e + 1810 Ne C. 189 F → 0+1 e + 188 F D. 189 F → 0+1 e + 188 O

D. 189 F → 0+1 e + 188 O

Rank the following by speed. α particle γ ray β particle

Fastest γ ray β particle α particle slowest

Classify the following as fusion, fission, or both.

Fission- used in nuclear power plants, byproducts have long half lives. Fusion- needs very high temps, occurs on the sun. Both- releases lots of energy

In the absence of an electric field, a radioactive beam strikes a fluorescent screen at a single point. When an electric field is applied, the radioactive beam is separated into three different components. One of the components is deflected toward the positive electrode because it is negatively charged, one of the components is deflected toward the negative electrode because it is positively charged, and one component is not deflected in any direction; instead, it moves along a straight path. Identify the charges possessed by the different components of the radioactive beam by observing their behavior under the influence of an electric field. α rays, γ rays, β rays

Negatively charged β rays Neutral γ rays Positively charged α rays

Fission involves the _________________ of an atom into smaller particles, while fusion occurs when smaller particles _________________.

Splitting, combine

α and β rays consist of particles, whereas γ rays are high-energy radiation and contain no particles and thus they have no mass. Given that the penetrating power decreases with mass, rank the rays (α rays, γ rays, β rays) according to their penetrating power.

Strongest γ rays β rays α rays Weakest

Which radioactive isotope would be used in the treatment of liver cancer?

Y-90

What is a rem?

a unit that measures the biological effects of different kinds of radiation

Which rem dosage causes symptoms of radiation sickness including nausea, vomiting, fatigue, and a reduction in white cell count? Which rem dosage causes symptoms of radiation sickness including nausea, vomiting, fatigue, and a reduction in white cell count? a. 15 rem b. 120 rem c. 550 rem d. 325 rem

b. 120 rem

Which of the following is appropriate shielding from gamma radiation? a. gloves b. lead c. lab coat d. paper

b. Lead

In the United States, the average person receives the largest dose of radiation from what source? a. television b. dental x-rays c. cosmic rays d. nuclear power plants

c. cosmic rays

The half-life of a radioisotope is _________

the time it takes for one-half of the sample to decay.

What values of x, y, and z complete this table? Concentration of C-14 % relative to living organisms------ Age of object (years) 100.0 -------------------------------------0 50.00 -----------------------------------5730 25.00----------------------------------- 11,460 x---------------------------------------- 17,190 y ----------------------------------------22,920 z ----------------------------------------28,650

x, y, z = 12.50, 6.250, 3.125 %

Identify the product of radioactive decay, and classify the given nuclear reactions accordingly.

α decay 24195Am→23793Np+? 28286Rn→27884Po+? β decay 146C→147N+? 23993Np→23994Pu+? γ decay 23793Np→23793Np+?

Match each description to a type of radiation: charge= 0, charge = -1, charge= +2, medium penetration mass = 0amu, least penetration, mass ~ 1/2000 amu deepest penetration, mass ~ 4 amu

α particle: charge = +2, mass ~4 amu, least penetration β particle: charge = -1, mass ~1/2000 amu, medium penetration γ ray: charge = 0, mass = 0amu, deepest penetration

Below are statements that summarize the characteristics of α, β, and γ rays. Identify the characteristics that correspond to each type of radiation.

α rays -It has the weakest penetrating power.It is symbolized as 4/2He.It is the most massive of all the components. β rays-It is a high-speed electron.It is symbolized as 0/−1e. γ rays- It has the strongest penetrating power.It possesses neither mass nor charge