Rank the following in order from the most energy released to the least energy released: (a) uranium-235 splitting into two equal fragments, (b) uranium-235 splitting into three equal fragments, (c) uranium-235 splitting into 92 equal fragments.

Rank the following physical and chemical changes in order of the amount of energy released, from least to greatest: (a) the condensation of rain in a thunderstorm, (b) the burning of a gallon of gasoline in a car engine, $(c)$ the explosion of a firecracker.

When food is irradiated with gamma rays from a cobalt-60 source, does the food become radioactive? Defend your answer.

Distinguish between an atom and an element.

U- 235 releases an average of $2.5$ neutrons per fission, while Pu-239 releases an average of $2.7$ neutrons per fission. Which of these elements might you therefore expect to have the smaller critical mass?

An anorexic girl shows high levels of acetone in her blood. What is this condition called, and what has caused it?

Scientists estimate the age of our universe to be about (a) 5000 years old. (b) 1 billion years old. (c) 14 billion years old. (d) 42 billion years old.

If a pair of carbon nuclei were fused and the product emitted a beta particle, what element would be produced?

Determine (a) the number of protons and neutrons in the missing fragment of the reaction shown below and (b) the mass of that fragment: $_{0}^{1} \mathrm{n}+_{92}^{235} \mathrm{U} \rightarrow ?+$ $_{54}^{136} \mathrm{Xe}$ $+12_{0}^{1} \mathrm{n}+126.5 \mathrm{MeV}$.

Why is there more carbon-14 in living bones than in once-living ancient bones of the same mass?

Rank these isotopes in order of their radioactivity, from the most radioactive to the least radioactive: (a) nickel-$59$, half-life $75,000$ years; (b) uranium-$238$, half-life $4.5$ billion years; $(c)$ actinium-$225$, half-life $10$ days.

Rank these isotopes in order of their radioactivity, from the most radioactive to the least radioactive: (a) nickel-59, half-life 75,000 years, (b) uranium-238, half-life 4.5 billion years, (c) actinium-225, half-life 10 days.

Which process would release energy from gold-fission or fusion? From carbon? (a) gold: fission; carbon: fusion (b) gold: fusion; carbon: fission $(c)$ gold: fission; carbon: fission (d) gold: fusion; carbon: fusion

What exactly is a chain reaction?