<span>The characteristics of a wave are given certain names to describe them, and this helps scientists to accurately describe any given wave. The characteristic known as frequency describes the number of waves that pass a point, and it is measured in waves per second, or Hertz, which is given the symbol Hz, but can also be described using the inverse of the SI unit for second, s^-1.</span>
Answer:

Explanation:
Hello there!
In this case, for these problems about collecting a gas over water, we must keep in mind that once the gas has been collected, the total pressure of the system is given by the atmospheric pressure, in this case 1.01 atm. Next, since we also have water in the mixture, we can write the following equation:

Thus, by solving for the pressure of nitrogen and using consistent units, we obtain:

The balanced equation is
4Fe+3O₂⇒2Fe₂O₃
We know that the mole of Fe₂O₃ is 6, and since the ratio between oxygen and <span>Fe₂O₃ is 3:2, we can see that
3:2 = x:6 (3 oxygen moles can make 2 </span>Fe₂O₃ moles = x oxygen moles can make 6 <span>Fe₂O₃ moles)
</span><span>
Multiply outside and inside (3*6 , 2*x) and put them on opposing sides of the equation
2*x = 3*6
2x=18
x=9
Therefore 9 moles of oxygen is needed.
</span>
Answer:
B. Changes in the Moon's visibility.
Explanation:
The moon's shifting of position makes it "appear" as being smaller or bigger. This is simply because the moon is rotating and the sun's light shines on a certain area of the moon, and depending on where we are on the Earth is how the moon looks or appears to our perspective.
Answer:
Hi
The Fermi Level is a term used to describe the set of electron energy levels at a temperature of absolute zero. Fermi's energy concept is important for the understanding of the electrical and thermal properties of solids. Both electrical and thermal processes involve energy values of a small fraction of an electron-volt. In thermal equilibrium, the net current of both electrons and holes is zero.
Explanation: