Unit - Basic Concepts of Chemistry and Chemical Calculations Evaluate yourself : . (i) Element - Copper wire, Silver plate (ii) Compound - Sugar, distilled water, carbon dioxide, Table salt, Naphthalene balls (iii) Mixture - Sea water . (i) C H OH : ( x ) + ( x ) + ( x ) + ( x ) = g (ii) KMnO : ( x ) + ( x ) + ( x ) g (iii) K Cr O : ( x ) + ( x ) + ( x ) g (iv) C H O : ( x ) + ( x ) + ( x ) g . (a) Molar mass of ethane, C H = ( x )+ ( x ) = g mol - n = mass / molar mass = g / g mol - = .
mole (b) At K and atm pressure mole of a gas occupies a volume of . L Therefore, number of moles of oxygen, that occupies a volume of ml at K and atm pressure . Κ mole K atm L L atm mole mole of oxygen contains . x molecules .
mole of oxygen contains = . x x . = . x molecules of oxygen .
(a) Mass of the metal = . g Mass of the metal chloride = . g . g of the metal combines with .
g of chlorine. Mass of the metal that combines with . g of chlorine is = . g eq – .
11th Std Chemistry 11th Std Chemistry - - - - (b) Equivalent mass of a oxidising agent = molar mass number of moles of electrons gained by one mole of the reducing agent g mol eq mol . g eq - . Element