I think it’s ffibtidgdggdy
Answer:
the first line
Explanation:
A rarefaction is a region in a longitudinal wave where the particles are furthest apart. ... The region where the medium is compressed is known as a compression and the region where the medium is spread out is known as a rarefaction.
use this picture as a reference:
Answer:
Equal to 0.253 mol.
Explanation:
Hello,
In this case, since hydrogen and water are in a 2:2 molar relationship, the number of moles of hydrogen necessary to produce 0.253 mol of water will be also 0.253 mol as shown on the following stoichiometric factor:

Therefore, The number of moles of hydrogen that is needed to produce 0.253 mol of water is equal to 0.253 mol.
Best regards.
Answer:
Negatively charged.
Explanation:
Hello!
In this case, since nonmetals arranged in groups 5A, 6A and 7A are able to attract the ionized form of metals (positive), we infer they are become negatively charged as they tend to gain electrons.
Some examples may be:

Regards!
The molarity is calculated using the following rule:
molarity = number of moles of solvent / volume of solution (in liters)
We have the volume of solution = 250 ml = 0.25 liters and the molarity = 3 m
Substituting in the equation, we get:
3 = number of moles / 0.25
number of moles = 3 x 0.25 = 0.75 moles