`CS_2` is a colourless, highly inflammable liquid used in the manufacture of rayon and cellophane. A sample contains 0.0205 mol `CS_2`. Calculate the mass of `CS_2` in the sample.

Boric acid, H_3 BO_3 is a mild antiseptic and is often used as an eye wash. A sample contains 0.543 mol H_3 BO_3 . What is the mass of boric acid in the sample?.

A water sample contains 1 millimole of Mg^(2+) ion per litre. Calculate the hardness of the water sample in ppm unit.

Nitric acid, HNO_3 is a colourless, corrosive liquid used in the manufacture of Nitrogen fertilizers and explosives. In an experiment to develop new explosives for mining operations, a 28.5 g sample of HNO_3 was poured into a beaker. How many moles of HNO_3 are there in this sample of HNO_3 ?

A water sample contains 1 millimole of Mg^(2+) ion per litre. calculate the hardness of water sample in ppm unit.

Calculate the number of O-atoms in 0.5 mol of SO_(2) .

Chlorophyll contains 2.68% of magnesium by mass. Calculate the no. of Mg atom in 2g of chlorophyll

Estimate the hardness of a sample of water 1L of which contains 0.001 mol of dissolved "MgCl"_(2)

10 g of a sample of Ca(OH)_2 is dissolved in 10 mL of 0.5 N HCL solution . The excess of HCl was titrated with 0.2 N NaOH. The volume of NaOH used was 10 cc. Calculate the percentage of Ca(OH)_2 in the sample.

2.5 g of an inpure sample of sodium bicarbonate when strongly heated gave 300ml of carbondioxide measured at 27^(@) and 760 mm pressure. Calculate the percentage purity of the sample. (Na=23, C=12, O=16).

A 2.5 mol sample of an ideal gas is compressed in reversible isothermal process from a volume of 12L to a volume of 5 L at 27^(@)C . Calculate the work done on the gas.