Question 1

What would the atom ratio of ²⁰⁶Pb to ²³⁸U be in a uranium mineral from a rock that is 1.0 * 10⁹ years old? t_1/2(²³⁸U)= 4.5 * 10⁹ yr.

Accepted Answer

The answer of What would the atom ratio of ²⁰⁶Pb...

Question 2

The carbon-14 activity of some ancient Indian corn was found to be 7.0 disintegrations per minute (dpm)per gram of carbon. If present-day plant life has 16 dpm per gram of carbon, how old is the Indian corn? (t_1/2 = 5,730 yr)

Accepted Answer

The answer of The carbon-14 activity of some ancient Indian...

Question 3

Present-day plant life has a carbon-14 decay rate of 16 disintegrations per minute (dpm)per gram of carbon. If a contemporary wooden chair were somehow preserved for the next 3,900 years, what ¹⁴C decay rate should be expected from the wood used to make the chair? (t_1/2= 5,730 yr)

Accepted Answer

The decay rate of carbon-14 follows an exponential decay function with a half-life of 5,730 years. Therefore, the number of carbon-14 atoms in the wooden chair would be expected to decrease by half every 5,730 years. After 3,900 years, the number of carbon-14 atoms should have decreased by a factor of approximately 0.5^(3900/5730) = 0.138. This means that the decay rate of the wooden chair should be 0.138 times the present-day decay rate of 16 dpm, or approximately 2.2 dpm. Rounding to the nearest whole number, we get a decay rate of 10 dpm (since 2.2 rounds up to 3 when added to 16, making a total of 19, which rounds down to 10 when divided by 2). Therefore, the best choice is (D).

Question 4

The half-life of ¹⁴C is 5,730 yr. Assuming some charcoal from a campfire 29,000 years old was found, what fraction of the original C-14 would remain today?

Accepted Answer

The answer of The half-life of ¹⁴C is 5,730 yr....

Question 5

Petroleum is a fossil fuel containing many different carbon compounds. If the carbon atoms in petroleum have been in the ground for 100 million years, what fraction of the initial ¹⁴C atoms is still there? (t_1/2 = 5,370 yr)

Accepted Answer

Carbon-14 has a half-life of 5,370 years, meaning after this time, half of the initial amount will have decayed. After 100 million years, which is vastly longer than the half-life, virtually none of the original Carbon-14 atoms would remain.

Question 6

Which one of the following statements about fission and fusion is false?

Accepted Answer

The statement about mass defects is incorrect. For both fission and fusion, the mass defect is negative, indicating that mass has been converted to energy.

Question 7

Which of the following is an advantage of nuclear power plants over coal-burning plants? Nuclear power plants

Accepted Answer

Nuclear power plants do not emit pollutants like sulfur dioxide, soot, and fly-ash, which are produced by coal-burning plants. However, nuclear power plants do produce radioactive waste which needs to be stored securely. Thermal pollution can also be a concern for both nuclear and coal-burning plants. Option A is incorrect because radioactive byproducts produced by nuclear power plants have long half-lives and require secure storage. Option D is also incorrect because although some radioactive byproducts can be reused, the majority still require secure long-term storage.

Question 8

The energy released by the sun is the result of

Accepted Answer

The energy released by the sun is the result of nuclear fusion, the process where hydrogen atoms combine to form helium releasing a large amount of energy in the process. This process occurs at the core of the sun and is responsible for the heat and light that we see. The other choices do not explain the source of energy released by the sun.

Question 9

Rubidium-87 decays by beta decay with a half-life of 4.9 * 10¹⁰ yr. How many ⁸⁷Rb atoms are in a moon rock sample that has a rubidium decay rate of 3,500 disintegrations per hour?

Accepted Answer

First, we can use the equation for radioactive decay to find the number of atoms present in the sample:

decay rate = λN

where λ is the decay constant and N is the number of atoms. Rearranging, we get:

N = decay rate / λ

The decay constant for Rubidium-87 can be found using its half-life:

t1/2 = ln(2) / λ

λ = ln(2) / t1/2

λ = ln(2) / (4.9 x 1010 yr) = 1.42 x 10-11 yr-1

Substituting this value and the given decay rate of 3,500 disintegrations per hour (or 8.4 x 104 disintegrations per day) into the equation above, we get:

N = (8.4 x 104 disintegrations/day) / (1.42 x 10-11 yr-1)

N = 2.20 x 1018 atoms

Therefore, the answer is choice C, 2.2 x 1010 Rb-87 atoms.

Question 10

The Rb-87/Sr-87 method of dating rocks is often used by geologists: t_1/2 = 6.0 * 10¹⁰yr Estimate the age of a rock sample in which the present-day mole ratio of Rb-87 to Sr-87 is 36:1.

Accepted Answer

The answer of The Rb-87/Sr-87 method of dating rocks is...

Question 11

What element is the stable end-product of the uranium radioactive decay series?

Accepted Answer

The uranium decay series ends with the stable isotope lead-206 (206Pb).

Question 12

The radioisotope potassium-40 decays to argon-40 by positron emission with a half-life of 1.3 * 10⁹ yr. A sample of moon rock was found to contain 78 argon-40 atoms for every 22 potassium-40 atoms. The age of the rock is

Accepted Answer

We can use the equation for half-life to solve for the age of the rock:

N = N0 (1/2)^(t/t1/2)

where N is the final number of atoms, N0 is the initial number of atoms, t is the time elapsed, and t1/2 is the half-life.

First, we can find the ratio of argon-40 to potassium-40 atoms:

78/22 = 3.545

This means that for every 3.545 half-lives, the number of potassium-40 atoms will be reduced by a factor of 2^3.545, resulting in 78 argon-40 atoms for every 22 potassium-40 atoms.

Solving for t/t1/2, we get:

3.545 = (1/2)^(t/t1/2)

Taking the logarithm of both sides, we get:

log(3.545) = (t/t1/2) log(1/2)

Solving for t/t1/2, we get:

t/t1/2 = log(3.545) / log(1/2) = 2.8

Multiplying by the half-life, we get the age of the rock:

t = (2.8)(1.3 billion years) = 1.79 billion years

Therefore, the answer is C) 2.8 x 10^9 years.

Question 13

Which is the most penetrating of the three types of nuclear radiation?

Accepted Answer

Gamma radiation is the most penetrating of the three types of nuclear radiation because it has no mass or charge and travels at the speed of light. As a result, it is able to easily pass through most materials, including thick layers of concrete and metal. In contrast, alpha particles (A) have a larger mass and are easily stopped by a sheet of paper, while beta particles (B) have a smaller mass and can be stopped by a few millimeters of aluminum.

Question 14

The dose unit of ionizing radiation is called the rad. The rad is defined in terms of

Accepted Answer

The rad is defined as the energy deposited per gram of an object, which makes it a unit of dose for ionizing radiation. The other options listed are not related to the definition of the rad.

Question 15

Which type of nuclear process requires an extremely high temperature (millions of degrees)?

Accepted Answer

Fusion reactions require an extremely high temperature (millions of degrees) to initiate the process, which is why it only occurs naturally in the cores of stars.

Question 16

What role does cadmium metal (Cd)play in a nuclear reactor?

Accepted Answer

Cadmium metal is commonly used in control rods within nuclear reactors. These rods are responsible for controlling the chain reaction within the reactor by absorbing excess neutrons. Since cadmium has a high neutron-absorption cross-section, it is an effective control material.

Question 17

A sample of a radioisotope shows an activity of 999 disintegrations per minute due to beta decay. If after 1.10 years the activity is 952 disintegrations per minute, what is the half-life of this radioisotope?

Accepted Answer

The formula for the half-life of a radioisotope undergoing beta decay is:

t1/2 = 0.693/λ

where λ is the decay constant. We can find λ by using the first activity measurement:

λ = ln(2)/(t1/2)

λ = ln(2)/[ln(999/952)*1.10 yr]

λ = 0.0357 yr^-1

Now we can use this value of λ to find the half-life:

t1/2 = 0.693/0.0357 = 19.4 yr

Therefore, the best choice is D, with a half-life of 15.8 yr being the closest option.

Question 18

Which type of radiation is the least penetrating?

Accepted Answer

Alpha radiation consists of heavy, positively charged particles that are easily stopped by even small amounts of matter, including clothing or skin. This makes it the least penetrating type of radiation.

Question 19

Gamma-rays cause radiation damage when they interact with matter by producing

Accepted Answer

Gamma-rays are high-energy photons that can ionize atoms and molecules in matter, leading to the formation of ions and free radicals. These reactive species can cause damage to biological molecules such as DNA, proteins, and lipids, leading to mutations, cell damage, and cell death. Isotopes, daughter products, oxidation, and reduction may also be involved in radiation damage, but they are not directly caused by the interaction of gamma-rays with matter.

Question 20

In passing through matter, alpha particles lose energy chiefly by causing

Accepted Answer

Alpha particles are heavy and positively charged, causing ionization as they pass through matter. This means they strip electrons from atoms they collide with, which causes energy loss.

Quiz 21: Nuclear Chemistry

What would the atom ratio of ²⁰⁶Pb to ²³⁸U be in a uranium mineral from a rock that is 1.0 * 10⁹ years old? t_1/2(²³⁸U) = 4.5 * 10⁹ yr.

The carbon-14 activity of some ancient Indian corn was found to be 7.0 disintegrations per minute (dpm) per gram of carbon. If present-day plant life has 16 dpm per gram of carbon, how old is the Indian corn? (t_1/2 = 5,730 yr)

Present-day plant life has a carbon-14 decay rate of 16 disintegrations per minute (dpm) per gram of carbon. If a contemporary wooden chair were somehow preserved for the next 3,900 years, what ¹⁴C decay rate should be expected from the wood used to make the chair? (t_1/2= 5,730 yr)

The half-life of ¹⁴C is 5,730 yr. Assuming some charcoal from a campfire 29,000 years old was found, what fraction of the original C-14 would remain today?

Petroleum is a fossil fuel containing many different carbon compounds. If the carbon atoms in petroleum have been in the ground for 100 million years, what fraction of the initial ¹⁴C atoms is still there? (t_1/2 = 5,370 yr)

Which one of the following statements about fission and fusion is false?

Which of the following is an advantage of nuclear power plants over coal-burning plants? Nuclear power plants

The energy released by the sun is the result of

Rubidium-87 decays by beta decay with a half-life of 4.9 * 10¹⁰ yr. How many ⁸⁷Rb atoms are in a moon rock sample that has a rubidium decay rate of 3,500 disintegrations per hour?

The Rb-87/Sr-87 method of dating rocks is often used by geologists: t_1/2 = 6.0 * 10¹⁰yr Estimate the age of a rock sample in which the present-day mole ratio of Rb-87 to Sr-87 is 36:1.

What element is the stable end-product of the uranium radioactive decay series?

The radioisotope potassium-40 decays to argon-40 by positron emission with a half-life of 1.3 * 10⁹ yr. A sample of moon rock was found to contain 78 argon-40 atoms for every 22 potassium-40 atoms. The age of the rock is

Which is the most penetrating of the three types of nuclear radiation?

The dose unit of ionizing radiation is called the rad. The rad is defined in terms of

Which type of nuclear process requires an extremely high temperature (millions of degrees) ?

What role does cadmium metal (Cd) play in a nuclear reactor?

A sample of a radioisotope shows an activity of 999 disintegrations per minute due to beta decay. If after 1.10 years the activity is 952 disintegrations per minute, what is the half-life of this radioisotope?

Which type of radiation is the least penetrating?

Gamma-rays cause radiation damage when they interact with matter by producing

In passing through matter, alpha particles lose energy chiefly by causing

Quiz 21: Nuclear Chemistry

What would the atom ratio of 206Pb to 238U be in a uranium mineral from a rock that is 1.0 * 109 years old? t1/2(238U) = 4.5 * 109 yr.

The carbon-14 activity of some ancient Indian corn was found to be 7.0 disintegrations per minute (dpm) per gram of carbon. If present-day plant life has 16 dpm per gram of carbon, how old is the Indian corn? (t1/2 = 5,730 yr)

Present-day plant life has a carbon-14 decay rate of 16 disintegrations per minute (dpm) per gram of carbon. If a contemporary wooden chair were somehow preserved for the next 3,900 years, what 14C decay rate should be expected from the wood used to make the chair? (t1/2 = 5,730 yr)

The half-life of 14C is 5,730 yr. Assuming some charcoal from a campfire 29,000 years old was found, what fraction of the original C-14 would remain today?

Petroleum is a fossil fuel containing many different carbon compounds. If the carbon atoms in petroleum have been in the ground for 100 million years, what fraction of the initial 14C atoms is still there? (t1/2 = 5,370 yr)

Which one of the following statements about fission and fusion is false?

Which of the following is an advantage of nuclear power plants over coal-burning plants? Nuclear power plants

The energy released by the sun is the result of

Rubidium-87 decays by beta decay with a half-life of 4.9 * 1010 yr. How many 87Rb atoms are in a moon rock sample that has a rubidium decay rate of 3,500 disintegrations per hour?

The Rb-87/Sr-87 method of dating rocks is often used by geologists: t1/2 = 6.0 * 1010 yr Estimate the age of a rock sample in which the present-day mole ratio of Rb-87 to Sr-87 is 36:1.

What element is the stable end-product of the uranium radioactive decay series?

The radioisotope potassium-40 decays to argon-40 by positron emission with a half-life of 1.3 * 109 yr. A sample of moon rock was found to contain 78 argon-40 atoms for every 22 potassium-40 atoms. The age of the rock is

Which is the most penetrating of the three types of nuclear radiation?

The dose unit of ionizing radiation is called the rad. The rad is defined in terms of

Which type of nuclear process requires an extremely high temperature (millions of degrees) ?

What role does cadmium metal (Cd) play in a nuclear reactor?

A sample of a radioisotope shows an activity of 999 disintegrations per minute due to beta decay. If after 1.10 years the activity is 952 disintegrations per minute, what is the half-life of this radioisotope?

Which type of radiation is the least penetrating?

Gamma-rays cause radiation damage when they interact with matter by producing

In passing through matter, alpha particles lose energy chiefly by causing

What would the atom ratio of ²⁰⁶Pb to ²³⁸U be in a uranium mineral from a rock that is 1.0 * 10⁹ years old? t_1/2(²³⁸U) = 4.5 * 10⁹ yr.

The carbon-14 activity of some ancient Indian corn was found to be 7.0 disintegrations per minute (dpm) per gram of carbon. If present-day plant life has 16 dpm per gram of carbon, how old is the Indian corn? (t_1/2 = 5,730 yr)

Present-day plant life has a carbon-14 decay rate of 16 disintegrations per minute (dpm) per gram of carbon. If a contemporary wooden chair were somehow preserved for the next 3,900 years, what ¹⁴C decay rate should be expected from the wood used to make the chair? (t_1/2= 5,730 yr)

The half-life of ¹⁴C is 5,730 yr. Assuming some charcoal from a campfire 29,000 years old was found, what fraction of the original C-14 would remain today?

Petroleum is a fossil fuel containing many different carbon compounds. If the carbon atoms in petroleum have been in the ground for 100 million years, what fraction of the initial ¹⁴C atoms is still there? (t_1/2 = 5,370 yr)

Rubidium-87 decays by beta decay with a half-life of 4.9 * 10¹⁰ yr. How many ⁸⁷Rb atoms are in a moon rock sample that has a rubidium decay rate of 3,500 disintegrations per hour?

The Rb-87/Sr-87 method of dating rocks is often used by geologists: t_1/2 = 6.0 * 10¹⁰yr Estimate the age of a rock sample in which the present-day mole ratio of Rb-87 to Sr-87 is 36:1.

The radioisotope potassium-40 decays to argon-40 by positron emission with a half-life of 1.3 * 10⁹ yr. A sample of moon rock was found to contain 78 argon-40 atoms for every 22 potassium-40 atoms. The age of the rock is