CHEMMMMMMMMMMM`

用戶242031

2008-05-05 9:07 am

1(a) calculate the % by mass of sodium in sodium carbonate-10-water,
Na2CO3．10H2O.

(b) find the masses of carbon and water of crystallization in 80g of
Na2CO3．10H2O.

回答 (1)

用戶7636

2008-05-05 9:28 am

✔ 最佳答案

1.a)
Molar mass of Na2CO3 ．10H2O
= 23(2) +12+16(3) +10(18)
=286
% by mass of sodium = 23(2) /286 x100%=16.1%

b)% by masses of carbon and water =[ 12+10(18) ]/286 x100% =67.1%
the masses of carbon and water of crystallization in 80g of
Na2CO3．10H2O
= 80 x 67.1% =53.7g

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