The items that are true of early nuclear science are "the first nuclear reactions were done in the 1880s" and "the first nucleus split was uranium-235." <span>The answers are letters A and D. It is impossible that nucleus was lost during the reaction as it will not follow the law of mass conservation.
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The answer would be the third one listed, Refraction
→ is the balanced chemical equation.
<h3>What is a balanced chemical equation?</h3>
A balanced chemical reaction is an equation that has equal numbers of each type of atom on both sides of the arrow.
Half-reaction method:
Unbalanced chemical equation:
→
Oxidation half-reaction:
→ I
Reduction half-reaction:
→
Balanced chemical equation:
→
Oxidation number method:
Unbalanced chemical equation:
→
→
→
Balanced chemical equation:
→
or
→
Hence, → is the balanced chemical equation.
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A chain reaction is a nuclear reaction that occurs when sufficient unstable nuclei are present so that when one splits (decays), its products hit other unstable nuclei, causing them to decay and initiating a chain reaction.
If this reaction goes uncontrolled, a massive explosion occurs. Such a reaction is the type that went uncontrolled when nuclear bombs were dropped over Hiroshima and Nagasaki in World War II. A chain reaction is much like dominoes all in a row; when one goes down, they all go down in order. The only way to block the chain reaction is to pull out a domino or to block the fall so the "chain" is broken.
The amount of fissionable material needed to accomplish a spontaneous chain reaction is called the critical mass. The critical mass for U-235 is about 1 kg. This explosive fission process takes place quickly, and an incredible amount of energy is released when it occurs.
So it would be C.