Hi friend
--------------
Your answer
-------------------
Water = H2O
Number of molecules in one mole of water = 6.022 × 10²³ [Avogadro's constant]
Given number of molecules = 2.52 × 10²³
So,
------
Number of moles =

HOPE IT HELPS
The question is incomplete, here is the complete question:
The decay constant for 14-C is
In 1947, the famous cave paintings in Lascaux, France were discovered and testing revealed that charcoal in the cave contained 20% of the 14-C found in living trees. Write a formula for the age of the charcoal (hence of the associated paintings). Show your work to find this formula.
<u>Answer:</u> The formula for the age of the charcoal is 
<u>Explanation:</u>
Carbon-14 isotope is a radioisotope and its decay process follows first order kinetics.
Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = 
t = time taken for decay process = ? yr
= initial amount of the sample = 100 grams
[A] = amount left after decay process = (100 - 20) = 80 grams
Putting values in above equation, we get:

Hence, the formula for the age of the charcoal is 
sorry what us this i don't get it
Answer:
5 g of H₂ are contained in the vessel
Explanation:
A typical excersise of conversion:
We determine molar mass of H₂.
This is a dyatomic molecule, as molar mass of H is 1g/mol, molar mass of H₂ will be 2g/mol.
Let's make the conversion of units:
2.5 mol . 2g/mol = 5 g
5 g of H₂ are contained in the vessel