Question

The combustion of palmitic acid is represented by the chemical equation: C16H32O2(s) + 23O2(g) → 16 CO2(g) + 16 H2O(l) The magnitude of ΔrU is ____________ in comparison to the magnitude of ΔrH a. The same b. Smaller c. Greater d. Need additional information

Answer 1

Answer:

The correct option is C

Explanation:

From the question we are told that

The reaction is

$C_{16}H_{32}O_2(g) + 23O_2(g) \to 16 CO_2(g) + 16 H_2O(l)$

Generally $\Delta H = \Delta U + \Delta N* RT$

Here $\Delta H$ is the change in enthalpy

$\Delta U$ is the change in the internal energy

              $\Delta N$  is the difference between that number of moles of product and the number of moles of reactant

Looking at the reaction we can discover that the elements that was consumed and the element that was formed is $O_2$ and  $CO_2$ and this are both gases so the change would occur in the number of moles

So  

$\Delta H = \Delta U + [16 -23]* RT$

$\Delta H = \Delta U -7RT$

The  negative sign in the equation tell us that the enthalpy$\Delta_r H$ would be less than the Internal energy $\Delta_r U$