Question

Calculate the enthalpy for the following reaction. During the reaction, the temperature changes from 42.5 C to 37 C. The specific heat of HCl is 4.04J/g*C. Is the reaction endothermic or exothermic?

Answer 1

`q = 0.810` Kj/mol

Its an endothermic reaction

Step-by-step explanation:

Enthalpy can be evaluated by using following formula -

`q = m * c* \delta T`

where

q is the enthalpy or change in internal energy

m is the mass in kg

c is the specific heat

and
`\delta T` is the change in temperature

Mass of HCl is equal to
`36.46` g/mol

or

Mass of HCl is equal to
`0.03646` Kg/mol

Substituting the given values in above equation, we get-

`q = 0.03646 * 4.04 * (42.5 - 37)\\q = 0.03646 * 4.04 * 5.5 \\`

`q = 0.810` Kj/mol

Enthalpy is positive thus it is an endothermic reaction