A 0.24 g sample of compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144g of oxygen. Calculate the percentage composition of the compound by weight.

The density of lake water is found to be 1.25 g mL^(-1) and contains 90 g Na^+ ions per Kg water. Calculate the molality of Na^+~ in the lake

In the estimation of sulphur by carius method, 0.468g of an organic sulphur compound yeilded 0.668g of barium sulphate.Find the percentage of sulphur in the given compound.

0.5g KCl was dissolved in 100g water and the solution originally at 20^@C , freeze at -0.24^@C . Calculate the percentage ionization of salt, K_f for per 1000g of water = 1.86K .

A sample of concentrated sulphuric acid used in the laboratory is 98% by mass in aqueous solution. If the density of the solution is 1.835 g mL^-1 . Calculate the molarity of the sulphuric acid sample.

Define the term 'mole'. Calculate mass in g of one atom of oxygen.

A solution of sucrose (molecular mass 342 u) is prepared by dissolving 6.84g in 100g of water at 298K. Calculate the boiling point of the solution. ( K_b for water, 0.52K mol^-1 )

A solution of sucrose (molecular mass 342 u) is prepared by dissolving 0.84 g in 100g of water at 298K. Calculate the freezing point of water in the solution. (K_f for water = 1.86 K kg mol^-1)

0.05 g of an organic compound was treated according to Kjeldahl's method. The ammonia evolved was absorbed in 50 ml of 0.5 MH_2SO_4 . The residual acid required 60ml of 0.5 M solution of NaOH for neutralization. Find the percentage composition of nitrogen in the given compound.