Answer:
There’s a particular way of writing what’s in a molecule called a chemical formula. The chemical formulae for all the elements that form each molecule and uses a small number to the bottom right of an element’s symbol to stand for the number of atoms of that element. For example, the chemical formula for water is H 2 O.
Explanation:
First we have to understand what a half life is. A half life is a measure of time when the amount of a certain object is 50% of the original amount. Hence the answer for this is letter A. The initial amount is 100. fifty percent of 100 is 50 and that happens after 15 hours. Hence, 15 hours is the half life period.
Na2SO4(aq)+Ba(NO3)2(aq)------------2NaNO3(aq)+BaSO4(s)
The mass of water that contains 2.5×10²⁴ atoms of Hydrogen is 74.79 g
<h3>Avogadro's hypothesis </h3>
From Avogadro's hypothesis,
6.02×10²³ atoms = 2 g of H
Therefore,
2.5×10²⁴ atoms = (2.5×10²⁴ × 2) / 6.02×10²³
2.5×10²⁴ atoms = 8.31 g of H
<h3>How to determine the mass of water </h3>
- 1 mole of water H₂O = (2×1) + 16 = 18 g
- Mass of H in 1 mole of water = 2 g
2 g of H is present in 18 g of water.
Therefore,
8.31 g of H will be present in = (8.31 × 18) / 2 = 74.79 g of water.
Thus, 2.5×10²⁴ atoms of Hydrogen is present in 74.79 g of water.
Learn more about Avogadro's number:
brainly.com/question/26141731
