Question

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Answer 1

Answer:

Here's what I get  

Explanation:

i. E = mc²

E = energy

m = mass

c = the speed of light

"Energy equals mass times the square of the speed of light.”

The equation says that energy and mass are interchangeable. If you multiply the mass of an object by c², you get its equivalent and of energy.

The SI base units for energy are kg·m²s⁻².  

The most common derived unit is the joule (J). Others are the newton-metre (N·m), kilowatt-hour (kWh), watt-second (W·s), and volt-coulomb (V·C).

ii. Nuclear vs chemical reactions

a. Alpha decay

$\rm _{92}^{238}\text{U} \longrightarrow \, _{2}^{4}\text{He} + \, _{90}^{234}\text{Th}$

A nuclear reaction — like α decay — takes place in the nucleus of an atom.

An element becomes a different element.

b. Chemical reaction

Na· + ·Cl ⟶ Na⁺ + Cl⁻

A chemical reaction — like the formation of NaCl — involves rearranging the electrons, which are outside the nucleus.

The elements do not change.

Salt still consists of sodium and chlorine.