Question

Enthalpy of combustion of carbon to CO2 is –393.5 kJ mol–1 . Calculate the heat released upon formation of 35.2 g of CO2 from carbon and dioxygen gas.​

Answer 1

Answer :

• Heat released = 314.8 kJ.

Step-by-step explanation:

Given that,

• Change in enthalpy(heat), ΔH = -393.5 kJ/mol.

Also,

• Molar mass of CO₂ = 44 g/mol.

$\rule{350}{1}$

The balanced chemical reaction for the combustion of C to CO₂ is as follows:-

$\rm{C(s)+O_2(g)\longrightarrow{}CO_2(g)\:;\:{\Delta}H=-393.5\:kJ\:mol^{-1}}$

Therefore, according to the reaction, 393.5 kJ of heat is released in the formation of 44 g(1 mol) of CO₂

Then, the formation of 35.2 g of CO₂ releases heat:-

$:\implies\rm{\dfrac{393.5\:kJ}{44\:g}\times{}35.2\:g}$

$:\implies\rm{\dfrac{393.5\times{}35.2}{44}}$

$:\implies\rm{\dfrac{13851.2}{44}=}\:\bold{314.8\:kJ.}$

Answer 2

Answer:

We know,

The reaction of combustion of carbon is

C(s) + O2(g)--->CO2(g);∆H=-393.5 KJ/mol

393.5 KJ heat released for the formation of 1 mole of CO2 gas.

e.g., for 44g CO2 formation heat released = 393.5 KJ

For 1g CO2 formation heat released = 393.5/44 KJ

So, heat released in the formation of 35.2 g of CO2 gas = 393.5 ×35.2/44 = 314.8 KJ

Hence, 314.8 KJ heat released upon the formation of 35.2 g of CO2.