Question

Consider the following thermodynamic formula for the combustion of acetone (C3H60): C3H60 (I) + 4 02 (g) 1 mole 4 moles 3CO2(g) 3 moles 3 moles + 3H2O (g) AH'on = -1790 kI a) How much heat is released if 3.48 g of acetone is completely burned at constant pressure? b) How many grams of acetone must be burned to release 267 kJ of heat?

Answer 1

C3H60 (I) + 4 02 (g) ----> 3CO2(g) + 3H2O (g)

So, 1 mole of acetone (C3H6O) gives -1790 kj/mol of heat

1 mole of acetone (58g) of acetone gives -1790 kJ/ mol

Now, using unitary method

3.48g of acetone will give

`(1790)/(58)\text{ * 3.48 = -107.4 KJ/ mol}`This answers a)

b) Since, 1790 kJ of heat is released by 58 g of acetone

267 kJ of heat will be released by

`(58)/(1790)*267\text{ =8.65 g}`