For the reaction of one mole of zinc dust with one mole of sulphuric acid in a bomb calorimeter, ∆U and w correspond to

Bomb calorimeter is commonly used to find the heat of combustion of organic substances which consists of a sealed combustion chamber, called a bomb.  li a process is run in a sealed container then no expansion or compression  is allowed, so w=0 and  ΔU=q. ΔU<0,w=0