5moles of an ideal gas (cp = 3r, cv 2r ) are heated from 25°c to 300°c. calculate (a) the change in internal energy of the gas (b) the change in enthalpy of the gas.

Answer :

(a) The change in internal energy of the gas is 22.86 kJ.

(b) The change in enthalpy of the gas is 34.29 kJ.

Explanation :

(a) The formula used for change in internal energy of the gas is:

where,

= change in internal energy = ?

n = number of moles of gas = 5 moles

= heat capacity at constant volume = 2R

R = gas constant = 8.314 J/mole.K

= initial temperature =

= final temperature =

Now put all the given values in the above formula, we get:

The change in internal energy of the gas is 22.86 kJ.

(b) The formula used for change in enthalpy of the gas is:

where,

= change in enthalpy = ?

n = number of moles of gas = 5 moles

= heat capacity at constant pressure = 3R

R = gas constant = 8.314 J/mole.K

= initial temperature =

= final temperature =

Now put all the given values in the above formula, we get:

The change in enthalpy of the gas is 34.29 kJ.

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.