Вариант 2.
1.
1) 4
2) 2
3) 2
4) 3
5) 1
6) 1
7) 35
8) 522
9) Na > Na2O > NaOH > Na2SO4.
1. 4Na + O2 >2 Na2O (натрий взят в избытке)
2. Na2O + H2O > 2NaOH
3. 2NaOH + H2SO4 > Na2SO4 + 2H2O.
10) Na2CO3 + Ca(OH)2 > 2NaOH + CaCO3.
m(Na2CO3) = 21,2 г
n(Na2CO3) = 21,2 / 106 = 0,2 моль
n(CaCO3) = n(Na2CO3) = 0,2 моль
> m(CaCO3) = 0,2 * 100 = 20 грамм.
ответ: m(CaCO3) = 20 грамм
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