Answer : The amount of heat released is, -121.04 KJ
Solution : Given,
Enthalpy of reaction, [tex]\Delta H_{rxn}[/tex] = -890 KJ
Mass of methane = 6 g
Molar mass of methane = 44 g/mole
First we have to calculate the moles of methane.
[tex]\text{Moles of methane}=\frac{\text{Mass of methane}}{\text{Molar mass of methane}}=\frac{6g}{44g/mole}=0.136moles[/tex]
The given balanced reaction is,
[tex]CH_4+2O_2\rightarrow CO_2+2H_2O[/tex]
From the balanced reaction we conclude that
1 mole of methane releases heat = -890 KJ
0.136 moles of methane releases heat = [tex]\frac{0.136moles}{1mole}\times -890KJ=-121.04KJ[/tex]
Therefore, the amount of heat released is, -121.04 KJ
Answer:
-333.75 KJ
Explanation:
From the reaction CH₄ + 2O₂ ⇒ CO₂ + 2H₂O ΔHrxn = -890 KJ.
From the reaction, 1 mole of CH₄ combusts to give -890 KJ.
We now calculate the number of moles, n of CH₄ in 6.00g
n = mass of CH₄/molar mass of CH₄
molar mass of CH₄ = 12 g/mol + 4 × 1 g/mol = (12 + 4) g/mol = 16 g/mol
mass of CH₄ = 6.00 g
n = 6.00 g /16 g/mol = 0.375 mol
So we have 0.375 mol of CH₄ in 6.00g
From the reaction, 1 mole of CH₄ produces -890 KJ
then 0.375 mol produces 0.375 mol × -890 KJ/1 mol = -333.75 KJ
