Найти массу оксида бария, который образуется при разложении 80 грамм карбоната бария, содержащего 5% примесей?

ПОМОГИТЕ, ПОЖАЛУЙСТА! желательно со всеми формулами и объяснениями...

 

 

Probably each person has the favourite toy - a childhood memory which it is difficult to leave. And I have a favourite toy - the small monkey with a white shaggy paunch, the rag legs put in checkered boots, filled by foam rubber. Small black eyes look at you from the hitretsy. This monkey to me presented on the kindergarten termination - I was six years old. In my hands the toy revived: could laugh or cry, use cunning or be angry. She was with me everywhere. The most important that the favourite toy bears with itself is associations. In me the passing on this toy causes tens memoirs of my childhood. First, carefree laughter which didn't die away in our house. Secondly, at the same time, this regret about the left childhood and how it was a little necessary for happiness. Whatever happened in my life, I could be firmly sure that its look will remain the same: derisive the consoling. Everything in life changes, but the person of a toy - a look in which your baby face and, unconscious then, sincere belief in good is reflected is invariable. Исправьте ошибки!

Какова массовая доля меди в оксиде меди 2? Пожалуиста помогите надо к завтрешнему!!

помогите решить KY+SO3--->K2SO3+Y2; ZnS+O2---->ZnO+SO2; SO2+N2S---->S+H2O; Cu+HNO3--->Cu(NO3)2+NO+H20