Answer:
a) 
b) 
Explanation:
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In this case, for this acid-base reaction which also known as a neutralization because sulfuric acid is neutralized with sodium hydroxide, we can write the undergoing chemical reaction as shown below:

However, it needs to be balanced as two sodium atoms are yielded:

Next, since there is a 1:2 mole ratio between the acid and the base, at the equivalence point, at which the moles of acid and base are consumed, we write:

Which can also be written in terms of the given volumes and concentration of the base:

In such a way, we solve for the concentration of sulfuric acid as shown below:

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Answer:
Element Y, or the third option
Explanation:
Alkanes are insoluble in water, but soluble in ether. Their boiling points are pretty low, barely reaching 200 degrees, so element Y is an alkane.
Answer:
Density is a physical quantity, defined as the ratio of body mass to the volume occupied by this body. The average body density is the ratio of body weight to its volume.
Since the mass in a body can be distributed unevenly, a more adequate model defines the density at each point of the body as a derivative of mass over volume.
Thus, to obtain the density of a sample, its mass must be divided by its volume. Thus, the density of the sample is 1.2 / 1.1, that is, 1.09 g/cm3.
Answer:
Option A. to build new cells.
Explanation:
All living things need nitrogen for the production of new cell because nitrogen is the main structural component of the cell. Protein is made up of amino acid and amino acid made of nitrogen. Without nitrogen atom, enzymes formation is impossible and we know that enzymes are necessary to speed up the chemical process. So nitrogen is very important for living organisms.
Answer:
A- Small ice pellets that may fall to the ground in a mixture of rain and snow in the form of a solid
Explanation:
Small ice pellets that may fall to the ground in a mixture of rain and snow in the form of a solid best describes hail.