Determining Whether An Object Is Actually Gold

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In summary, a gold crown with a mass of 14.7 kg is found to have a mass of 13.4 kg when submerged in water. The question is whether the crown is made of pure gold or a gold and copper compound, and what the ratio of gold to copper would be in the latter case. The density of gold is 19.32 and the density of copper is 8.96. Using the law of buoyancy, which states that the weight of fluid displaced is equal to the buoyant force, this information can help in determining the composition of the crown.
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chucas11
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A gold crown hangs from a spring scale reading it's mass as 14.7 Kg. When the crown is submerged in water while still hanging from the spring scale, it's mass now reads 13.4 kg. Knowing that its either all gold, or a gold and copper compound, figure out which of the two it is. If it is a gold and copper compound, what are their ratios. Density of Au=19.32, Density of Cu=8.96.

I'm stuck, not really even sure where to start. :(. Any tips or help would be greatly appreciated. I do not by any means want anyone to do this for me. A nudge in the right direction would be great.
 
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A law of buoyancy says the difference between the two weights is the weight of fluid displaced. Is that enough of a nudge?
 
  • #3
More simply put: The buoyant force is equal to the weight of the displaced fluid.
 

FAQ: Determining Whether An Object Is Actually Gold

How can I determine if an object is made of real gold?

There are a few ways to determine if an object is actually made of gold. One method is to use a magnet - gold is not magnetic, so if the object is attracted to the magnet, it is not gold. Another method is to scrape the surface of the object and apply a drop of nitric acid - if the area turns green, the object is not gold. However, the most accurate way to determine if an object is made of gold is to have it tested by a professional using specialized equipment.

What are some common characteristics of real gold?

Real gold is typically a bright, yellow color and has a high level of luster or shine. It is also very malleable and can be easily bent or shaped without breaking. Additionally, real gold is usually quite heavy and dense compared to other metals of the same size.

Can an object be partially made of gold?

Yes, it is possible for an object to be made of a combination of materials, including gold. For example, a piece of jewelry may have a gold-plated surface over a base metal. In this case, the object would not be considered entirely made of gold, but would still contain some gold content.

Are there any other materials that can be mistaken for gold?

Yes, there are several materials that can be mistaken for gold, such as pyrite (also known as "fool's gold"), brass, and bronze. These materials may have a similar appearance to gold, but they have different properties and can be easily differentiated with the proper testing methods.

Is it possible for the gold content in an object to be fake or altered?

Yes, it is possible for the gold content in an object to be fake or altered. For example, some counterfeit coins or jewelry may have a thin layer of real gold on the surface, but the majority of the object is made of a different, less valuable metal. It is important to have the gold content of an object tested by a professional to ensure its authenticity.

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