Some Basic Concepts of Chemistry - 1 - JEE MCQ

The hydrated salt Na₂SO₄.nH₂O, undergoes 55% loss in weight on heating and becomes anhydrous. The value of n will be

Insulin contains 3.4% sulphur. What will be the minimum molecular weight of insulin ?

How many moles of electron weight one kilogram ?

The largest number of molecules is present in

25 g of NaOH is dissolved in 50 mL of water. The molarity of the solution is

Calculate percentage change in M_avg of the mixture, if PCl₅ undergo 50% decomposition.

PCl₅ → PCl₃ + Cl₂

Calculate the weight of lime (CaO) obtained by heating 200 kg of 95% pure lime stone (CaCO₃).

A carbon compound containing carbon and oxygen has molar mass equal to 288. On analysis it is found to contain 50% by mass of
each element. Therefore molecular formula of the compound is -

Four one litre flasks are separately filled with the gases hydrogen, helium, oxygen and ozone at the same room temperature and pressure.
The ratio of total number of atoms of these gases present in the different flasks would be

The mass of 2 gram atoms of calcium

What volume of 0.4-M FeCl₃.6H₂O will contain 600 mg of Fe³⁺ ?

At 100ºC and 1 atm, if the density of liquid water is 1.0 g cm^–3 and that of water vapor is 0.0006 g cm^–3, then the volume occupied by water molecules in 1 litre of steam at that temperature is -

Volume of a gas at NTP is 1.12 × 10^–7 c.c. The number of molecules in it will be -