# How Much Lead Can Be Melted with 1000 Joules Starting at 20°C?

• mawalker
In summary, the question is asking for the maximum mass of lead that can be melted with 1000 J of heat, starting from 20 degrees Celsius. The melting point of lead is 328 degrees Celsius, and its specific heat and latent heat of fusion are also given. The final temperature would be 328 degrees Celsius, and the total energy required for melting and raising the temperature would be 1000 J. Therefore, to find the mass, we can use the equation Q = Mc delta T, where delta T is equal to the change in temperature during the first step (raising the temperature) and 0 during the second step (melting). Solving for the mass gives us 25.36 grams. However, this is
mawalker
This is the question...

What is the maximum mass of lead you could melt with 1000 J of heat, starting from 20C?

Tm = 328 degrees C
Lf (j/k) = 0.25 x 10 ^5
Tb = 1750 degrees C
Lv = 8.58 x 10^5

but I'm not really sure what i need to use. Q = Mc delta T

but how can you figure this without having an ending temperature? I'm confused. Anyone have an idea?

Hint: Assume the lead has just melted. What's its final temperature?

Hint2: Think of there being two steps:
(1) Raising the temperature

the lead begins to melt at 328 degrees celsius. so this would be the final temperature?

Sounds right to me.

ok so delta T = 308. c of lead = 128, setting up my equation 1000J = M(128)(308)... 1000 = 39424M M = .02536 kg. M = 25.36 g and this is the wrong answer.

mawalker said:
ok so delta T = 308. c of lead = 128, setting up my equation 1000J = M(128)(308)... 1000 = 39424M M = .02536 kg. M = 25.36 g and this is the wrong answer.
Looks like you only considered the first step (raising the temperature) and not the second (the actual melting). The total energy of those two steps equals 1000 J.

i don't really understand. what would be the change in temperature during the melting? wouldn't it just be zero? or would it just keep increasing?

During the state change (step 2) the temperature doesn't change, but energy is still required to melt a given mass of lead. Consider the latent heat of fusion.

## What is the maximum amount of lead that can be melted?

The maximum amount of lead that can be melted depends on various factors such as the size and capacity of the melting equipment, the type of heating method used, and the purity of the lead. Generally, smaller melting equipment can melt up to a few hundred pounds of lead, while larger industrial equipment can melt several thousand pounds.

## How is the maximum amount of lead that can be melted determined?

The maximum amount of lead that can be melted is determined by the melting point of lead, which is approximately 327 degrees Celsius or 621 degrees Fahrenheit. However, the actual amount that can be melted also depends on the melting rate and the melting efficiency of the equipment being used.

## What happens if the maximum amount of lead is exceeded during melting?

If the maximum amount of lead is exceeded during melting, it can lead to overheating of the equipment and potentially cause damage. It can also affect the melting efficiency and the quality of the melted lead. It is important to follow the manufacturer's recommended maximum capacity for safe and efficient melting.

## Is there a limit to how much lead can be melted at once?

Yes, there is a limit to how much lead can be melted at once. This limit is usually determined by the size and capacity of the melting equipment. Attempting to melt more lead than the recommended maximum capacity can be dangerous and can also affect the quality of the resulting melted lead.

## Can the maximum amount of lead that can be melted be increased?

The maximum amount of lead that can be melted cannot be increased beyond the capacity of the melting equipment. However, upgrading to a larger or more efficient melting equipment can increase the maximum amount of lead that can be melted at one time. It is important to consult with a professional and follow safety guidelines when increasing the maximum melting capacity.

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