Economic importance of nickel
Batteries, hot coils and a powder catalyst
1. Economic importance of the first transition series
2. The red-hot coil
A hair dryer coil glows red hot every day, yet it lasts for years. What does it need?
Pick the right answer
Predict: what must a heating coil resist?
- A. Corrosion at high temperature
- B. Nothing: it only needs to conduct electricity well
- C. Magnets near the coil
Explanation
A heating coil is hot and meets air all day, and hot metal reacts faster with air, so the coil must resist corrosion at high temperature. That is why nickel-chromium alloys are used in heating coils.
3. 8- Nickel: batteries, alloys, plating
| Use | What the book says |
|---|---|
| Nickel-cadmium battery | can be recharged |
| Nickel-steel alloys | hard; resist rust and the effect of acids |
| Nickel plating | protects other metals from oxidation and rust; gives them a beautiful appearance |
Remember: rusting is the corrosion of iron in moist air.
An alloy is a metal mixed with other elements. You'll study alloys later.
4. Heating coils
Nickel-chromium alloys are used in heating coils and electric furnaces because they resist corrosion at high temperature.
True or false?
The book's reason for using nickel-chromium alloys in heating coils is that they conduct electricity well.
Explanation
The book says nickel-chromium alloys are used in heating coils and electric furnaces because they resist corrosion at high temperature, not because of how well they conduct.
5. Nickel check
Pick the right answer
A bakery oven has heating coils that glow red hot for hours every day. Why use a nickel-chromium alloy for them?
- A. They resist corrosion at high temperature
- B. They are good conductors of electricity
- C. They can be recharged
Explanation
Coils that glow red hot for hours need a material that resists corrosion at high temperature; that is the book's reason for using nickel-chromium alloys in heating coils. Recharging belongs to the nickel-cadmium battery.
Pick the right answer
A company wants steel bicycle handlebars that don't rust and look shiny. Which nickel use fits best?
- A. Nickel plating
- B. A nickel-cadmium battery
- C. Finely divided nickel
Explanation
Nickel plating covers other metals, protecting them from oxidation and rust and giving them a beautiful appearance, which is what the handlebars need.
6. Finely divided nickel
Remember: a catalyst speeds up a reaction without being used up.
Finely divided nickel is used as a catalyst in the hydrogenation of oils.
Hydrogenation of oils
Adding hydrogen to liquid oils, for example to make solid ghee.
arraycoil + H2\\ \ finely divided Ni\\ hydrogenated oilarray
7. Why a fine powder?
Cut a 1 cm cube of nickel into smaller cubes. The mass stays the same. Watch the surface.
Pieces along each edge 1
Small cubes 1
Total surface area 6 cm²
True or false?
A lump of nickel works as well as the same mass of finely divided nickel.
Explanation
The reaction happens on the surface of the nickel. The same mass as a fine powder has a much larger total surface area than a lump, so finely divided nickel works better as a catalyst.
8. Match the reason
Sort into groups
Sort each reason under the nickel use it explains.
Resists corrosion at high temperatureGives metals a beautiful appearanceHas a very large surface areaProtects other metals from oxidation and rust
Pick the right answer
Two flasks hold oil and hydrogen. One gets 5 g of nickel lumps; the other gets 5 g of finely divided nickel. What happens?
- A. The finely divided nickel gives faster hydrogenation
- B. Both work at the same rate, because the mass is the same
- C. The lumps work faster, because they are heavier pieces
Explanation
Both flasks have 5 g of nickel, but the finely divided nickel has a much larger surface area, and the reaction happens on the surface, so its flask is hydrogenated faster.
9. Summary
Back to the coil: nickel-chromium alloys resist corrosion at high temperature.
| Nickel use | What the book says |
|---|---|
| Nickel-cadmium battery | can be recharged |
| Nickel-steel alloys | hard; resist rust and the effect of acids |
| Nickel-chromium alloys: heating coils, electric furnaces | resist corrosion at high temperature |
| Nickel plating | protects other metals from oxidation and rust; gives them a beautiful appearance |
| Finely divided nickel | catalyst in the hydrogenation of oils |
Can you explain why the nickel catalyst is used as a fine powder?