Answer : 0.25 M
explanation :
- Molarity is the number of moles of solute per liters of solvent.
- Molarity (M) = (n) / V (liter) = 2 / 8 = 0.25 M
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:
pH value of a solution depends on the concentration of hydrogen ions
(pH = -log[H+(aq)].
Hydrochloric acid is a strong acid, while ethanoic acid is a weak acid. Strong acids ionize completely in water (to give ions which includes H+(aq)), while weak acids only ionize partially in water.
Therefore, even if both hydrochloric acid and ethanoic acid are monobasic acids (each molecule can ionize completely to give 1 hydrogen ion), since hydrochloric acid ionizes completely in water and ethanoic acid does not ionize completely, the concentration of hydrogen ions in hydrochloric acid is higher than that of ethanoic acid, leading to a lower pH value for hydrochloric acid, while higher for ethanoic acid.
Answer : (C) Hafnium is the most likely identity of the given substance.
Solution : Given,
Mass of given substance (m) = 46.9 g
Volume of given substance (V) = 3.5 
First, find the Density of given substance.
Formula used :
Now,put all the values in this formula, we get
= 13.4 g/
So, we conclude that the density of given substance (13.4 g/) is approximately equal to the density of Mercury and Hafnium (13.53 and 13.31 g/ respectively).
According to the question the substance is solid at room temperature but Mercury is liquid at room temperature. So, Mercury is not identical to the given substance.
Another element i.e, Hafnium is the element whose density is approximately equal to the given substance and also solid at room temperature. And we know that the melting point of solid is high.
So, Hafnium is the most likely element which is the identity of the given substance.
