ICSE Class 10 Chemistry 2013 Solved Paper

Show Para  Hide Para 
O2 is evolved by heating KClO3 using MnO2 as a catalyst
2KClO3
MnO2
─────▸
2
‌KCl
+3O2
© examsnet.com
Question : 78
Total: 84
Calculate the number of moles of oxygen present in the above volume and also the number of molecules.
Solution:  
245g of KClO3 contains
=3‌ moles of oxygen ‌
∴24.5g of KClO3 contains
‌=‌
3×24.5
245

‌=0.3‌ mole. ‌ Ans.
Since, 1 mole of oxygen contain
=6.022×1023‌ molecules ‌
Therefore, 0â‹…3 mole of oxygen contain
‌=6.022×1023×0.3
‌=1.8066×1023‌ molecules ‌
© examsnet.com
Go to Question: