# Question ce200

##### 1 Answer
Feb 25, 2016

The reaction will release 159.0 kJ.

#### Explanation:

Given:

Balanced equation

Mass of ${\text{SO}}_{2}$

ΔH_f

Find:

Heat released

Strategy:

1. Use the molar mass to convert mass of $\text{S}$ to moles of $\text{S}$.
2. Use the molar ratio from the equation to convert moles of $\text{S}$ to moles of ${\text{SO}}_{3}$.
3. Use ΔH_"f" to calculate the heat released.

Solution:

1. Moles of $\text{S}$

$\text{Moles of S" = 6.44 color(red)(cancel(color(black)("g S"))) × "1 mol S"/(32.06 color(red)(cancel(color(black)("g S")))) = "0.2009 mol S}$

2. Moles of ${\text{SO}}_{3}$

$\text{2S" + "3O"_2 → "2SO"_3; ΔH_f = "-791.4 kJ}$

${\text{Moles of SO"_3 = 0.2009 color(red)(cancel(color(black)("mol S"))) × (color(red)(cancel(color(black)(2))) "mol SO"_3)/(color(red)(cancel(color(black)(2))) color(red)(cancel(color(black)("mol S")))) = "0.2009 mol SO}}_{3}$

3. Heat released

ΔH = 0.2009 color(red)(cancel(color(black)("mol SO"_3))) × "-791.4 kJ"/(2 color(red)(cancel(color(black)("mol SO"_3)))) = "-159.0 kJ"#

The reaction releases 159.0 kJ of heat.