Tube worms that survive near geothermal vents of hydrogen sulfide rely on bacteria living inside them to obtain energy by the oxidation of H2S to SO4^2-. What is the overall change in the oxidation number of sulfur for this reaction?
-2 in H2S
+6 in SO4^2-
To determine the overall change in the oxidation number of sulfur in the given reaction, let's break it down and track the oxidation state of sulfur.
The reaction can be represented as follows:
H2S (hydrogen sulfide) + O2 (oxygen) → SO4^2- (sulfate)
First, let's assign oxidation states to the elements based on their usual rules:
- Hydrogen (H) typically has an oxidation state of +1.
- Oxygen (O) typically has an oxidation state of -2.
Now, let's assign the oxidation state of sulfur (S) in each compound:
- In H2S, hydrogen typically has an oxidation state of +1, so the overall oxidation state of sulfur must be -2 to balance it out. Therefore, sulfur in H2S has an oxidation state of -2.
- In SO4^2-, oxygen typically has an oxidation state of -2. Since there are four oxygen atoms, the total negative charge is -8. To neutralize this, the oxidation state of sulfur must be +6 to balance out the charges. Therefore, sulfur in SO4^2- has an oxidation state of +6.
So, let's calculate the change in the oxidation number of sulfur:
Initial oxidation state of sulfur in H2S = -2
Final oxidation state of sulfur in SO4^2- = +6
To get the overall change, subtract the initial oxidation state from the final oxidation state:
+6 - (-2) = +8
Therefore, the overall change in the oxidation number of sulfur in this reaction is +8.
To determine the overall change in the oxidation number of sulfur in the reaction where H2S is oxidized to SO4^2-, we need to examine the oxidation states of sulfur in each compound.
The oxidation state of hydrogen is usually +1, and oxygen is typically -2.
For H2S (hydrogen sulfide), hydrogen has an oxidation state of +1, so the oxidation state of sulfur is -2.
For SO4^2- (sulfate), each oxygen has an oxidation state of -2. Since there are four oxygen atoms in SO4^2-, the total oxidation state from oxygen is -2 x 4 = -8. The overall charge of SO4^2- is -2, so the oxidation state of sulfur can be calculated by adding the total oxidation state from oxygen to the overall charge.
Let's denote the oxidation state of sulfur in SO4^2- as x.
-8 + x = -2
x = -2 + 8
x = +6
Therefore, the oxidation state of sulfur changes from -2 in H2S to +6 in SO4^2-, resulting in an overall change in oxidation number of +8.