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.

Question

The group 14 elements A and B have the first ionisation enthalpy values of 708 and 715 kJ mol$^{-1}$ respectively. The above values are lowest among their group members. The nature of their ions A$^{2+}$ and B$^{4+}$ respectively is:

Answer 1

Given enthalpy of combustion of carbon:

C(s) + O2(g) -> CO2(g)}, (Delta)H = -393.5 kJ mol^-1

This means formation of 1 mol (44 g) of CO₂ releases 393.5 kJ of heat.

Step 1: Moles of CO₂ in 35.2 g

CO2 = 44g mol}^{-1} = 35.2 44 g mol^-1 = 0.8 mol

Step 2: Heat released for 0.8 mol CO₂

(Delta) H = 0.8 (-393.5) kJ = -314.8 kJ

The heat released upon formation of 35.2 g of CO₂ from carbon and dioxygen is: \[ \boxed{q \approx -3.15 \times 10^{2}\ \text{kJ} \; \text{(i.e. } -314.8\ \text{kJ)}} \]

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.

Solution and Explanation

Top Questions on Enthalpy change

Questions Asked in CBSE Class XI exam

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.

Solution and Explanation

Top Questions on Enthalpy change

Questions Asked in CBSE Class XI exam

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.