Question

Calculate the amount of heat transferred when 24.0g of CH3OH(g) is decomposed by this reaction at constant pressure.For a given sample of CH3OH , the enthalpy change during the reaction is 82.6kJ . What mass of methane gas is produced?How many kilojoules of heat are released when 38.7g of CH4(g) reacts completely with O2(g) to form CH3OH(g) at constant pressure?

Answer 1

Answer:

94,4 kJ of heat transferred.

10,5 g of CH₄ gas are produced.

304 kJ are released.

Explanation:

The reaction is:

2 CH₃OH(g) → 2 CH₄(g) + O₂(g) ΔH = +252 kJ

24,0 g of CH₃OH(g) are:

24,0g CH₃OH×$\frac{1mol}{32,04186g}$ = 0,749 moles of CH₃OH(g)

As two moles of CH₃OH(g) transferred +252 kJ, 0,749 moles of CH₃OH(g) transferred:

0,749 molesCH₃OH×$\frac{+252 kJ}{2moles}$ = 94,4 kJ

When 2 moles of CH₄ are produced, the enthalpy change is +252 kJ. 82,6 kJ are:

82,6kJ×$\frac{2moles}{252 kJ}$= 0,656 moles of CH₄

0,656 moles of CH₄ are:

0,656 moles of CH₄×$\frac{16,05 g}{1mol}$ = 10,5 g of CH₄

38,7 g of CH₄(g) are:

38,7g CH×$\frac{1mol}{16,05g}$ = 2,41 moles of CH₄(g)

As two moles of CH₄ released 252 kJ, 2,41 moles of CH₄(g) released:

2,41 moles CH₄×$\frac{+252kJ}{2moles}$ = 304 kJ

I hope it helps!