Melting Ice With Aluminum?

In summary, the problem involves calculating the amount of aluminum at 90 degrees C needed to melt 10 g of ice at 0.0 degrees C. This can be solved by finding the heat energy required to melt the ice (333.7 kJ) and using the specific heat capacities of aluminum and ice to determine the mass of aluminum needed with a temperature difference of 90 degrees C.
  • #1
BlueSkyy
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0
Melting Ice With Aluminum??

Homework Statement



How many grams of aluminum at 90 degrees C would have to be dropped into a hole in a block of ice at 0.0 degrees C to melt 10 g of ice?

Homework Equations



Q = (m)(c)(deltaT)
c of aluminum = 0.9
c of ice = 2.1
c of water = 4.186
333.7 kJ is needed to get past the ice/water boundary

The Attempt at a Solution



I've tried setting up a few different equations, like:
(.01 kg)(2.1)(+45) + (x kg)(0.9)(-45) = 0
(.01 kg)(2.1)(+45) + 333.7 + (x kg)(0.9)(-45) = 0
and a few others I don't have on hand, but I can't seem to get the correct answer. What do I use for delta T? Am I even doing this right at all?

Thanks for your help.
 
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  • #2
No, I think you are missing it. First calculate the heat energy Q needed to melt 10 g of ice. Your latent heat of fusion should read 333.7 kJ/kg. Then solve for the mass of aluminum having this value of Q, using deltaT=90C (since the final temp of the Al is 0C once it's done its job).
 
  • #3


I would suggest using the equation Q = m x c x deltaT to solve this problem. In this case, we want to find the mass (m) of aluminum needed to melt 10 g of ice, so we can rearrange the equation to solve for m:

m = Q / (c x deltaT)

First, we need to calculate the heat required to melt 10 g of ice. This can be done using the heat of fusion of water, which is 333.7 kJ/kg. Therefore, the total heat required to melt 10 g of ice is:

Q = (10 g)(333.7 kJ/kg) = 3337 J

Next, we need to determine the change in temperature (deltaT) of the aluminum as it cools from 90 degrees C to 0 degrees C. This can be calculated using the specific heat capacity of aluminum, which is 0.9 J/g x degrees C:

deltaT = 90 degrees C - 0 degrees C = 90 degrees C

Now, we can plug these values into the equation to solve for the mass of aluminum needed:

m = (3337 J) / (0.9 J/g x degrees C x 90 degrees C) = 41.6 g

Therefore, approximately 41.6 grams of aluminum at 90 degrees C would need to be dropped into the ice to melt 10 g of ice at 0 degrees C. Keep in mind that this is an ideal calculation and does not take into account any heat loss or other factors that may affect the actual amount of aluminum needed.
 

1. How does aluminum melt ice?

Aluminum is a highly reactive metal that is able to release a large amount of energy when it comes into contact with water. When aluminum is placed on ice, it reacts with the water molecules, causing a chemical reaction that generates heat. This heat melts the ice, allowing the aluminum to sink into the water and continue the reaction until all the ice has melted.

2. What makes aluminum a good material for melting ice?

Aluminum has a low melting point of 660.32°C, which is much lower than other common metals such as iron and copper. This means that it can easily melt and release its energy when placed on ice, making it an effective material for melting ice.

3. Is aluminum safe to use for melting ice?

Aluminum is generally considered safe to use for melting ice. However, it is important to handle it with care as it can become very hot when reacting with water. It is also important to properly dispose of the aluminum after use to prevent any potential environmental harm.

4. Can aluminum be reused for melting ice?

Yes, aluminum can be reused for melting ice multiple times. However, the effectiveness of the aluminum may decrease over time as it becomes coated with a layer of oxide, which can hinder its reaction with water. To maintain its effectiveness, the aluminum can be cleaned with a mild acid solution before each use.

5. Are there any other materials that can be used to melt ice besides aluminum?

Yes, there are other materials that can be used to melt ice such as calcium chloride, sodium chloride, and magnesium chloride. These materials are often used in de-icing salts and work by lowering the freezing point of water, causing the ice to melt. However, these materials can also be harmful to the environment and should be used carefully.

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