Q = m . C . Δ T
q : Heat absorbed
m : mass of the sample
C : The specific heat of the substance.
Δ T : The change in temperature (Final T - initial T)
So:
q = 15.5 x 4.18 x (50 - 25) = 1619.75 J
V2O5 is the formula. Vanadium has a charge of +5 and oxygen is -2, so to make them equal, you need to double the vanadium charge and multiply the oxygen charge by 5
First, we determine the energy released by the reaction using the heat capacity and change in temperature as such:
Q = cΔT
Q = 32.16 * 0.42
Q = 13.51 kJ
Next, we determine the moles of ammonia formed as the heat of formation is expressed in "per mole".
Moles = mass / molecular weight
Moles = 5/17
Moles = 0.294
Heat of formation = 13.51 / 0.294
The heat of formation of ammonia is 45.95 kJ/mol
Occurs at a specific temperature