Answer:
The nucleus represents a major evolutionary transition. As a consequence of separating translation from transcription many new functions arose, which likely contributed to the remarkable success of eukaryotic cells. Here we will consider what has recently emerged on the evolutionary histories of several key aspects of nuclear biology; the nuclear pore complex, the lamina, centrosomes and evidence for prokaryotic origins of relevant players.
Answer:

Explanation:
To convert from atoms to moles, we must Avogadro's number:
This number tells us the amount of particles (atoms, molecules, etc.) in 1 mole of a substance. In this case, it is atoms of magnesium in 1 mole.
- 6.022 *10²³ atoms Mg / 1 mol mg
Now, let's set up an expression using:

Multiply this by the given number of atoms.

Flip the fraction so the atoms of magnesium can cancel.


Multiply and condense this into 1 fraction.


The original measurement had 3 significant figures, so our answer must have that many as well. For the number we calculated, that is the tenth place. The 6 in the hundredth place tells us to round the 1 to a 2.

It is about <u>92.2 moles of magnesium.</u>
Answer : The correct option is, (B) Salicylic acid
Solution :
First we have to calculate the moles of salicylic acid and acetic anhydride.


Now we have to calculate the limiting and excess reagent.
The balanced chemical reaction is,

From the balanced reaction we conclude that
As, 2 moles of salicylic acid react with 1 mole of acetic anhydride
So, 0.507 moles of salicylic acid react with
mole of acetic anhydride
The excess of acetic anhydride = 0.783 - 0.2535 = 0.5295 moles
That means the in the given balanced reaction, salicylic acid is a limiting reagent because it limits the formation of products and acetic anhydride is an excess reagent.
Hence, the limiting reagent is, salicylic acid.
Answer:
8×10^(-3) mol/L
Explanation:
The formula for finding the hydrogen ion concentration is...
[H⁺] = 10^-ph
[H⁺] = 10^(-2.1)
[H⁺] = 0.00794...mol/L = 8×10^(-3) mol/L
The answer is to 1 significant digit because the pH has one decimal place.