How do you calculate enthalpy given the temperature?

Answer 1

Specific Heat is:

-the amount of energy required to raise the temperature of 1g of a substance 1°C

-specific heat is symbolised as Cp or C

-has units of J/g °C

-J stands for Joules, which is a unit of energy

Most often used in equation: q = mΔTCp

q = energy in J

m = mass in g

ΔT = change in temperature

Cp = specific heat

ExampleHow much energy is required to raise the temperature of 345.34g of Aluminium from 35.0°C to 250.00°C ? The specific heat of Aluminium is .90 J/Cp

q = mΔTCp

q = 345.34g(250.00°C - 35.0°C)0.09J/g°C

from there its just simple Algebra.

q = 66,823.29J

However, not all problems will be as simple as the one above. Some may require up to 3+ equations that can include Enthalpy or ΔH which leads to using a Change of State Graph.

Answer 2

(Enthalpy is the heat content of a system at constant pressure).

(A thermochemical equation is a chemical equation that includes enthalpy change).

The change in enthalpy is represented in equations as delta H.

Make sure that the thermochemical equation is balanced. Then determine whether this is an endothermic or exothermic. ( if the delta H value given is positive, then the reaction is endothermic. if it is negative, then it is exothermic). If the reaction is endothermic, then add the delta H value to the reactants (right side of the equation) in kJ. If it is exothermic, add it to the products (left side) in kJ.

****If needed use Hess' Law

1. if reverse equation, then change the sign on the delta H value

2. if multiply/divide the equation, then do the same to the delta H value

3. add equations and add delta H values

Answer 3

Draw a born-haber cycle.

Remember that the sum of the reactions enthalpy change is all of the individual changes added together.

You could use Hess' law to draw one of his triangle things, but i find that difficult.

Answer 4

Enthalpy of a chemical species is expressed in joules/mol. No temperature unit is included in enthalpy and thus temperature does not play a role in its calculation.

change in enthalpy = enthalpy of reactants - enthalpy of products

enthalpy values of chemical species can be found in a merck index

Answer 5

To calculate enthalpy given the temperature, you would need additional information such as the specific heat capacity of the substance. The formula for calculating enthalpy change is ΔH = mcΔT, where ΔH is the enthalpy change, m is the mass of the substance, c is the specific heat capacity, and ΔT is the temperature change.

Answer 6

There are many possible types of chemistry problems; it is not possible to give a generic answer for all of them.