The Thermit process is used for repairing cracks in railway tracks on site.
(a) Write the equation for the reaction taking place in the process, mentioning the physical states of the reactants and products.
(b) What information in the chemical equation indicates that the reaction is exothermic?

What is a thermochemical equation? Explain why is it essential to mention the physical states of reactants and products in thermochemical equations.

No chemical reaction takes place when granules of a rusty brown solid A re mixed with the powder of another solid B. however, when the mixture is heated, a reaction takes place between its components. One of the products C is a metal and settles down in the molten state while the other product D floats over it. it was observed that the reaction is highly exothermic. (a) What could the solids A and B be? (b) What are the products C and D most likely to be? (c) Write the chemical equation for the reaction between A and B leading to the formation of C and D. Mention the physical states of all the reactants and products in this equation and indicate tthe heat change which takes place. (d) What is the special name of such a reaction? State one use of such a reaction. (e) Name any two types of chemical reaction under which the above reaction can be classified.