3.0e23 atoms Ne
"E" means 10^
Then we multiply it by a mole of Ne. By the definetion of a mole, it is always 6.022e23 atoms of an element.
So now, we do this:
3.0e23 atoms Ne x (1 mol Ne / 6.022e23 atoms Ne)
After that, we use molar mass. A mole of Neon is equal, in terms of grams, to its avg. atomic mass. This goes true for any element.
It ends up like this:
3.0e23 atoms Ne x (1 mol Ne / 6.022e23 atoms Ne) x (20.1797 g Ne / 1 mol Ne)
Now cancel out the "atoms Ne" and "1 mol Ne"
You end up with a grand total of...
*plugs everything into a calculator*
10.05298... g Ne.
We need to round to 2 sig. figs. (3.0) so now it's....
10 g Ne.
Note that this method can only be used for converting atoms of an element to mass in grams.
Source(s):
A periodic table for the atomic mass of neon.
A chemistry textboook
A chemistry class.
Answer:

Explanation:
Hello,
In this case, it is widely known that for isochoric processes, the change in the enthalpy is computed by:

Whereas the change in the internal energy is computed by:
So we compute the initial and final temperatures for one mole of the ideal gas:

Next, the change in the internal energy, since the volume-constant specific heat could be assumed as ³/₂R:

Then, the volume-pressure product in Joules:

Finally, the change in the enthalpy for the process:

Best regards.
Answer:
See explanation below
Explanation:
You are missing the structure, therefore, I will do an example with one that I found on another place to try to explain.
This acid mechanism always involves carbocations, and positive charges, never negative because we are in acidic mediums.
In the first step, the lone pairs of the oxigen from the epoxide, substract one hydrogen of the reactant.
Second step, the lone pairs of the oxygen from the reactant, do a nucleophylic attack to the carbon of the epoxide. In this case, it will do it to the most substitued carbon.
Then, in the third step by acid base equilibrium, the hydrogen from the reactant that attacked, is substracted from the molecule by a molecule of water (We are in acid medium, therefore, there is traces of water) and the final structure is formed.
Check picture for mechanism: