<span>2,5 х моль
</span>
<span>2KMnO4 = K2MnO4 + MnO2 + O2</span>
<span>2 моль 1 моль</span>
<span>n = m/M</span>
<span>M(KMnO4) = 39 + 55 + 16*4 = 158 г/моль</span>
<span>n(KMnO4) = 395 <span>г</span> / <span>158 г/моль</span> = 2,5 моль</span>
<span><span><span>2,5</span></span> = <span><span>х</span></span></span>
<span> 2 1</span>
<span>х = 1,25</span>
<span><span>n(O2) = 1,25 моль</span></span>
<span><span>V = Vm*n</span></span>
<span><span>V(O2) = 22,4 дм3/моль * 1,25 моль = 28 дм3</span></span>
<span><span>Ответ: 28 дм3</span></span>