Question

Calculate the percentage composition of various elements in Na₂SO₄.10H₂O​

Answer 1

Explanation:

Your goal here is to figure out how many grams of water you have in

100 g

of sodium sulfate decahydrate,

Na

2

SO

4

⋅

10

H

2

O

.

To do that, start with what you know. More specifically, start with the fact that

1

mole of sodium sulfate decahydrate contains

one mole of sodium sulfate,

1

×

Na

2

SO

4

ten moles of water,

10

×

H

2

O

You also know that sodium sulfate has a molar mass of

142.04 g mol

−

1

and that water has a molar mass of

18.015 g mol

−

1

. This means that

1

mole of sodium sulfate decahydrate contains

1

×

142.04 g

→

sodium sulfate

10

×

18.015 g

→

water

and has a total mass of

142.04 g

.

+

10

×

18.105 g

=

322.19 g

This means that

100 g

of sodium sulfate decahydrate will contain

100

g Na

2

SO

4

⋅

10

×

18.015 g H

2

O

322.19

g Na

2

SO

4

=

55.9 g H

2

O

Therefore, you can say that the percent composition of water in this hydrate is equal to

% H

2

O

=

55.9

%

−−−−−−−−−−−−−−−

Keep in mind that the

%

sign means out of

100 g

of hydrate.

Answer 2

Explanation- Molar mass of Na

2

SO

4

.10H

2

O=323

Molar mass of water in it t is mass of 10H

2

O=180

∴ % of water of crystallisation =

323

180

×100

=55.72%

I hOpe iTs hElP yOu...

pLz mArK mE bRaInLieSt :):):)