Question

Based on the thermochemical equation 2 C₄H₁₀ + 13 O₂ → 8 CO₂ + 10 H₂O ΔH = -5316 kJ,

if (4.75x10^1) g of C₄H₁₀ (MM = 58.14 g/mol) reacted with excess oxygen, how many kJ of heat would be released?

Please show work

Answer 1

Given 2 C4H10 + 13 O2 → 8 CO2 + 10 H2O ΔH = -5316 kJ,

Now the ΔH indicates the net amount of heat relased or absorbed in a reaction

Since here the value of ΔH is negative, it indicates from the combustion of 2 moles of C4H10, 5316 kJ of heat is released.

Now given mass of C4H10 taken = (4.75x10^1) g = 47.5 g

So moles of C4H10 taken = mass / molar mass of C4H10

= 47.5 g / 58.14 g/mol

= 0.8 moles

So heat relased from combustion of 0.8 moles of C4H10 = 5316 kJ / 2 * 0.8

= 2,171.5 kJ

So 2,171.5 kJ of heat is released from complete combustion of  (4.75x10^1) g of C4H10