Calculate the molar mass of the following compounds. 
i) urea [CO(NH₂)₂]
ii) Acetone [CH₃ COCH₃]
iii) Boric Acid [H₃ BO₃]
iv) Sulphuric  Acid [H₂ SO₄]

The reaction between aluminium and ferric oxide can generate temperatures up to 3273 K and is used in welding metals. (Atomic mass of AC = 27 u atomic mass of O = 16 u )
2Al + Fe₂O₃ \(\longrightarrow \) Al₂O₃ + 2Fe;  If in this process, 324 g of aluminum is allowed to react with 1.12 kg of ferric oxide
i) Calculate the mass of Al₂O₃ formed
ii) How much of the excess reagent is left at the end of the reaction ?

A Compound on analysis gave Na = 14.31% S = 9.97% H = 6.22% and 0 = 69.5%.
Calculate the molecular formula of the compound if all the hydrogen in the compound is present in combination with oxygen as a water of crystallization. (molecular mass of the compound is 322).

Balance the following equations by ion electron method.
i) \({ KMn }O_{ 4 }+{ SnCl }_{ 2 }+HCI\longrightarrow MnCI_{ 2 }+{ SnCI }_{ 4 }+{ H }_{ 2 }O+KCI\)
ii) 
iii) 
iv) 

Calculate the percentage composition of the elements present in magnesium carbonate. How many kilogram of CO₂ can be obtained by heating 1 kg of 90 % pure magnesium carbonate.