148,290 views
12 votes
12 votes
Been struggling on this one someone please help me.

Been struggling on this one someone please help me.-example-1
User Wube
by
2.6k points

1 Answer

6 votes
6 votes

Answer:

-1706.6 kJ/mol

Step-by-step explanation:

For this question, they're asking us to solve for delta H and give us the numbers we will be using under certain molecules.

The formula for this problem (also known as Hess's Law) is:

ΔHf = ΣΔH products − ΣΔH reactants

First let's plug in for the first part asked, the product part:

In our equation we have 2ZnO(s) + 2SO2(g) on our product side. Below these molecules we will be using the values given in the question.

Let's go ahead and plug in the values:

[2(-350.5) + 2(-296.8)]

**Notice I am including a 2 in front of the values. This is because they have a coefficient (number in front of the molecule) that means there is 2 of those molecules present.

Now let's do for the second part of the equation:

In our reactant side we have 2ZnS(s) + 3O2(g). Notice how Oxygen has a value of 0. This is because all elements (not combined with some other element) will always have a value of 0 when solving for Hess's Law.

Now let's go ahead and plug in the values:

[2(-206.0) + 3(0)]

Let's now combine the two and solve for the final answer:

[2(-350.5) + 2(-296.8)] - [2(-206.0) + 3(0)]

-1706.6 kJ/mol.

User Greg Tatum
by
2.7k points