I am dropping back to just one post a day for a while. There is plenty in the back catalogue if you need more.
Happy Christmas!
Melchior is an alloy of copper and nickel used to make coins and cutlery. It is silvery in colour and particularly resistant to corrosion, even in saltwater. One version of the alloy (containing 30% nickel, 0.8% iron, 1% manganese and 68.2% copper) is used to make condenser tubes like the ones shown in the diagram below.
This is rather like an inside out Liebig condenser. Cold water is passed through the tubes then steam is passed into the shell where it condenses and drains out through the bottom. Steam turbines in power stations use an arrangement like this for two purposes. The first is to use hot ‘used’ steam from the turbines to boil more water to generate steam for secondary turbines. The second use is to condense the steam so that the water can be fed back to the boiler. You can see this process in the schematic diagram shown below.
In the middle of the picture is the heat recovery steam generator and below that is the condenser. Melchior alloy would be a good choice for the condenser tubes because it would not be corroded by the steam.
Questions…
- What is the chemical symbol for…
- nickel
- iron
- manganese
- copper
- In saltwater, what is the solute and what is the solvent?
- Suggest one chemical property of iron that makes it different from the other three metals listed above.
- What physical property does nickel have that only one of the other three metals shares?
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