Nuclear Chemistry

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What is the critical condition for an atomic bomb to work?

The size of the fissile material should not be less than the critical size (correct)
The size of the fissile material should be exactly equal to the critical size
The size of the fissile material should be less than the critical size
The size of the fissile material should be more than the critical size

What happens when the amount of U 235 exceeds a few kilograms?

Neutrons emitted during fission escape
Neutrons emitted during fission are absorbed by adjacent nuclei causing further fission (correct)
Neutrons emitted during fission cancel each other out
Neutrons emitted during fission react with other elements

What is the result of a nuclear chain reaction caused by U 235 fission?

No energy is released
A vast quantity of energy is released (correct)
The energy released is unpredictable
A small amount of energy is released

What is the difference between nuclear fission and spallation reactions?

Spallation reactions involve high energy bombarding particles or photons (B) Signup and view all the answers

What is the most common element capable of undergoing nuclear fission?

Uranium (B) Signup and view all the answers

What is the name of the process by which U 235 undergoes fission?

Nuclear fission (C) Signup and view all the answers

What is the term used to describe the phenomenon of certain elements undergoing spontaneous disintegration without external influence?

Radioactivity (D) Signup and view all the answers

Who is credited with the discovery of radioactivity in 1891?

Henry Becquerel (C) Signup and view all the answers

What is the term used to describe the study of the composition of atomic nuclei and nuclear transformations?

Nuclear Chemistry (A) Signup and view all the answers

What is the term used to describe the process in which a non-radioactive substance becomes radioactive after exposure to radiation?

Induced Radioactivity (C) Signup and view all the answers

What is the purpose of devices such as ionisation chamber, Geiger Muller counter, and scintillation counter?

To detect and measure radioactivity (A) Signup and view all the answers

What is the term used to describe nuclear reactions that involve the combination of atomic nuclei to form a heavier nucleus?

Nuclear Fusion (C) Signup and view all the answers

What is the type of nuclear reaction that occurs when a heavier atom like uranium-235 is split into smaller fragments?

Nuclear fission (C) Signup and view all the answers

Which of the following isotopes of uranium undergoes fission by slow moving neutrons?

U-235 (C) Signup and view all the answers

What is the purpose of a nuclear reactor?

To obtain nuclear energy in a controlled way for peaceful purposes (B) Signup and view all the answers

Which of the following elements is used in a nuclear reactor to slow down neutrons?

Graphite (D) Signup and view all the answers

What was the composition of the atomic bomb used in Hiroshima?

U-235 (C) Signup and view all the answers

Who discovered that uranium-235 splits up into two relatively lighter elements when bombarded with neutrons?

Hahn and Startsman (A) Signup and view all the answers

What happens when the neutron-to-proton ratio in a nucleus is higher than required for stability?

The nucleus emits a β- ray (D) Signup and view all the answers

What is the relationship between the rate of radioactive decay and the amount of the radioactive element present?

The rate of radioactive decay is directly proportional to the amount of the radioactive element present (A) Signup and view all the answers

What is the significance of the decay constant λ in the equation for radioactive decay?

It is independent of temperature and is a characteristic of the radioactive element (A) Signup and view all the answers

What is the effect of a lower neutron-to-proton ratio in a nucleus than required for stability?

Any of the above options (D) Signup and view all the answers

What is the order of the reaction in radioactive decay?

First order (B) Signup and view all the answers

What is the energy of activation for radioactive decay?

Zero (D) Signup and view all the answers

What is the primary reason why Radium is about 3 million times more radioactive than uranium?

Radium has a more unstable nucleus (D) Signup and view all the answers

What is the characteristic of α-rays emitted by a radioactive substance?

They have a positive charge and a 4-unit mass (D) Signup and view all the answers

What is the result of a radioactive substance emitting radiations by itself?

The substance exhibits natural radioactivity (C) Signup and view all the answers

What is the difference between β-rays and γ-rays emitted by a radioactive substance?

β-rays have a negative charge and γ-rays have no charge (D) Signup and view all the answers

Why do certain elements undergo spontaneous disintegration without external influence?

Due to their unstable nucleus (D) Signup and view all the answers

What is the primary reason why Rutherford was able to split the radiations emitted by a radioactive substance into α, β, and γ-rays?

He applied electric and magnetic fields to the radiations (B) Signup and view all the answers

What is the result of a decrease in the neutron-proton ratio in a radioactive nucleus?

An increase in the stability of the nucleus (A) Signup and view all the answers

What is the consequence of a radioactive nucleus emitting an alpha-particle?

A decrease in the atomic number of the nucleus by 2 (B) Signup and view all the answers

What is the relationship between the packing fraction and the stability of a nucleus?

A lower packing fraction indicates a more stable nucleus (A) Signup and view all the answers

What is the role of the neutron-proton ratio in determining the stability of a nucleus?

A lower neutron-proton ratio indicates a more stable nucleus (A) Signup and view all the answers

What is the consequence of a radioactive nucleus emitting a beta-particle?

An increase in the atomic number of the nucleus by 1 (C) Signup and view all the answers

What is the relationship between the binding energy and the stability of a nucleus?

A higher binding energy indicates a more stable nucleus (B) Signup and view all the answers