3. Mothballs in a clothes closet gradually disappear over time. What happens to this material?
1 answer:
Mothballs in a clothes closet gradually disappear over time, because their components sublime.
Mothballs are small balls of chemical pesticide and deodorant, sometimes used in closets where clothes are susceptible to damage from mold or moths. Mothballs are usually made of naphthalene, 1,4-dichlorobenzene or camphor. What all the compounds have in common is that they sublime at room temperature. Sublimation is a physical change in which matter changes from the solid to the gas state. Once the components are in the gaseous state, the diffuse, and that's why there are no visible remainings over time.
Mothballs in a clothes closet gradually disappear over time, because their components sublime.
You can learn more about sublimation here:
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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
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.