Question

when 1 gram of anhydrous oxalic acid is burnt at 25 degree Celsius the amount of heat liberated is 2.835 kilos Delta which combustion is

Answer 1

 

Well, the question is not too much clear but I assume you want to know about the heat of combustion.

So, Heat of combustion of a substance is actually the heat which is liberated when 1 mole of substance undergoes the full and complete combustion with the help of oxygen while pressure is kept constant.

So Molar mass o anhydrous oxalic acd( C2H2O4) is equals to 90.03 g/mol

In the question it I mentioned that 1 g oxalic acid  combustion at 25 degree celsius gives heat  = 2.835 KJ

Thus, 90 g oxalic acid combustion at 25 degree celsius will liberat heat =  2.835 * 90.03 = 255.23 KJ/mole (delta H)

Answer 2

Molar mass of C2H2O4 = 90g

Burning of 1g of C2H2O4 = - 2.835KJ

Burning of 90g of C2H2O4 =90×-2.835

=-255.15kJ