Economic importance of vanadium and chromium
Hard springs, a busy oxide and a strong oxidizing agent
1. Economic importance of the first transition series
2. Springs that last
A car spring is squeezed thousands of times on bumpy roads. Why doesn't it crack or rust away?
Pick the right answer
Predict: the steel of car springs contains vanadium. How much?
- A. A small portion added to the steel
- B. About half of the spring is vanadium
- C. The spring is made of pure vanadium
Explanation
A small portion of vanadium is added to the steel. It forms an alloy of high hardness that resists corrosion, so it is used to make car springs.
3. 3- Vanadium in steel
Remember: corrosion slowly eats a metal away in air and moisture.
When we add a small portion of vanadium to steel, an alloy of high hardness forms. It has a great ability to resist corrosion. So it is used in the manufacture of car springs.
An alloy is a metal mixed with other elements. You'll study alloys later.
- Steel + a small portion of vanadium → High hardness alloy that resists corrosion
- High hardness alloy that resists corrosion → Car springs
4. Vanadium pentoxide (V₂O₅)
V2O5
Dyes
In the manufacture of ceramics and the glass industry
Catalyst
Speeds up a reaction without being used up
Magnetic conductors
In the manufacture of strong magnetic conductors
5. Vanadium check
Pick all that apply
Which of these are uses of vanadium pentoxide (V2O5)? Choose all that apply.
- A. Dyes in the manufacture of ceramics and glass
- B. A catalyst
- C. Manufacture of strong magnetic conductors
- D. Car springs
- E. Leather tanning
Explanation
V2O5 has three uses: dyes for ceramics and glass, a catalyst, and strong magnetic conductors.
6. 4- Chromium and its compounds
Chromium is a chemically active metal, but it resists the effect of atmospheric air. Chromium is used in metal plating and leather tanning.
| Substance | Use |
|---|---|
| Chromium (Cr) | Metal plating; leather tanning |
| Chromium III oxide (Cr2O3) | Manufacture of dyes |
| Potassium dichromate (K2Cr2O7) | Oxidizing agent |
Why does an active metal resist air? A later lesson explains it.
7. An oxidizing agent
Remember: an oxidizing agent oxidizes another substance. It is itself reduced.
Potassium dichromate, K2Cr2O7, is used as an oxidizing agent. It makes other substances undergo oxidation.
| Agent | What it does | Example in this lesson |
|---|---|---|
| Oxidizing agent | oxidizes another substance and is itself reduced | K2Cr2O7 |
| Reducing agent | takes oxygen away from another substance | H2, CO |
8. Vanadium or chromium?
Sort into groups
Sort each use by the element it comes from (the metal or one of its compounds).
Car springs (added to steel)Metal platingLeather tanningA catalystStrong magnetic conductorsAn oxidizing agent
Pick the right answer
A lab adds potassium dichromate to a reaction mixture. What is its job?
- A. It oxidizes another substance, and is itself reduced
- B. It takes oxygen away from another substance
- C. It speeds up the reaction and is not used up
- D. It colours the mixture as a dye
Explanation
Potassium dichromate (K2Cr2O7) is used as an oxidizing agent: it oxidizes another substance and is itself reduced.
9. Summary
Back to the springs: a small portion of vanadium makes steel very hard and corrosion resistant.
- V in steel: high hardness alloy, resists corrosion: car springs.
- V2O5: dyes in ceramics and glass, a catalyst, strong magnetic conductors.
- Cr: metal plating and leather tanning. Cr2O3: dyes.
- K2Cr2O7: an oxidizing agent.
Can you explain why V2O5 is more than just a dye?
Reveal
Besides dyes for ceramics and glass, V2O5 is an important catalyst (it speeds up a reaction and is not used up) and is used in the manufacture of strong magnetic conductors.