Answer:
3.25×10²⁴ molecules
Explanation:
From the question given above, the following data were obtained:
Mass of H₂O = 97.2 g
Number of molecule of H₂O =?
From Avogadro's hypothesis, we understood that:
1 mole of H₂O = 6.02×10²³ molecules
Next, we shall determine the mass of 1 mole of H₂O. This can be obtained as follow:
1 mole of H₂O = (2×1) + 16
= 2 + 16
= 18 g
Thus,
18 g of H₂O = 6.02×10²³ molecules
Finally, we shall determine the number of molecules in 97.2 g of H₂O. This can be obtained as follow:
18 g of H₂O = 6.02×10²³ molecules
Therefore,
97.2 g of H₂O = 97.2 × 6.02×10²³ / 18
97.2 g of H₂O = 3.25×10²⁴ molecules
Thus, 97.2 g of H₂O contains 3.25×10²⁴ molecules.
It means it depends on how much of the chemical you have. For ex. if 1 drop of snake venom might not kill you, but 20 drop could definitely kill you. Hope this helps!
Preparing 15 mg/gl working standard solution from a 20 mg/dl stock solution will require the application of the dilution principle.
Recalling the principle:
initial volume x initial molarity = final volume x final molarity
Since we were not given any volume to work with, we can as well just take an arbitrary volume to be prepared. Let's assume that the stock solution is 10 mL and we want to prepare 15 mg/gl from it:
Applying the dilution principle:
10 x 20 = final volume x 15
final volume = 200/15
= 13.33 mL
This means that in order to prepare 13.33 mL, 15 mg/l working standard solution from 10 ml, 20 mg/dl stock solution, 3.33 mL of the diluent must be added to the stock solution.
More on dilution principle can be found here: brainly.com/question/11493179
