Question

How many molecules of H2O are contained in 2.48 g of Na2 S2 03.5H2 O (at .wt.ofNa=23,S= 32​

Answer 1

Answer:

The number of molecules of water in 2.48g of that compound would be

$3 \times {10}^{22} \: molecules$

Explanation:

First of all convert the given mass into moles by the relation

$number \: of \: moles \: = \: \frac{mass \: in \: grams}{molar \:mass}$

Thus the number of moles = 2.48 / 248

= 0.01 mol

Now we know that there are

$6.023 \times {10}^{23} \: molecules$

in one mole of a compound,

and also from the formula it is clear that each one molecule of that compound contain Five molecules of water hence the total number of water molecules woul be

$= 0.01 \times 5 \times 6.023 \times {10}^{23} \\ = 0.301 \times {10}^{23} \\ = 3.01 \times {10}^{22} \: molecules$