`MnO_(2)` on ignition converts into `Mn_(3)O_(4)`. A sample of pyrolusite having 75% `MnO_(2)`, 20% inert impurities and rest water is ignited in air to constant mass. What is the percentage of Mn in the ignited sample ?

40 g Ba(MnO_(4))_(2) (mol.mass=375) sample containing some inert impurities in acidic medium completely reacts with 125 mL of "33.6 V" of H_(2)O_(2) . What is the percentage purity of the sample ?

The average atomic mass of a sample of an element X is 16.2 u, what are the percentages of isotopes "_8^16X and "_8^18X in the sample?

A certain sample of cuprous sulphide is found to have composition Cu_(1.8)S, , because of imcroporation of Cu^(2+) ion in the lattice, What is the mole % of Cu^(2+) in total content in this crystal?

Total charge required to convert three moles of Mn_(3)O_(4) to MnO_(4)^(c-2) in present of alkaline medium

Oleum is considered as a solution of SO_(3) in H_(2)SO_(4) , which is obtained by passing SO_(3) in solution of H_(2)SO_(4) When 100 g sample of oleum is diluted with desired mass of H_(2)O then the total mass of H_(2)SO_(4) obtained after dilution is known is known as % labelling in oleum. For example, a oleum bottle labelled as ' 019% H_(2)SO_(4) ' means the 109 g total mass of pure H_(2)SO_(4) will be formed when 100 g of oleum is diluted by 9 g of H_(2)O which combines with all the free SO_(3) present in oleum to form H_(2)SO_(4) as SO_(3)+H_(2)O to H_(2)SO_(4) 1 g of oleum sample is diluted with water. The solution required 54 mL of 0.4 N NaOH for complete neutralization. The % free SO_(3) in the sample is :

Oleum is considered as a solution of SO_(3) in H_(2)SO_(4) , which is obtained by passing SO_(3) in solution of H_(2)SO_(4) When 100 g sample of oleum is diluted with desired mass of H_(2)O then the total mass of H_(2)SO_(4) obtained after dilution is known is known as % labelling in oleum. For example, a oleum bottle labelled as ' 019% H_(2)SO_(4) ' means the 109 g total mass of pure H_(2)SO_(4) will be formed when 100 g of oleum is diluted by 9 g of H_(2)O which combines with all the free SO_(3) present in oleum to form H_(2)SO_(4) as SO_(3)+H_(2)O to H_(2)SO_(4) If excess water is added into a bottle sample labelled as "112% H_(2)SO_(4) " and is reacted with 5.3 g NaCO_(3) then find the volume of CO_(2) evolved at 1 atm pressure and 300 K temperature after the completion of the reaction :

2.0g of a sample contains mixture of SiO_2 and Fe_2O_3 . On very strong heating, it leaves a residue weighing 1.96 g . The reaction responsible for loss of mass is given below. Fe_2O_3(s)rarrFe_3o_4(s)+O_2(s) , (unbalance equation) what is the percentage by mass of SiO_2 in original sample ?

A sample containing HAsO_2 (mol. mass =180 ) and weighing 3.78g is dissolved and diluted to 250mL in a volumetric flask. A 50mL sample (aliquat) is withdrawn with a pipet and titrated with 35mL of 0.05 M solution of I_2 . Calculate the percentage HAsO_2 in the sample :