[PwnageBR]

So I got a few small chunks of potassium alum, and wanted to melt it to make 1 big chunk

According to many websites, potassium alum melts at ≈ 92°C (200 °F). It is also transluscent

So I took a small piece of it, to test if it really worked

When I got it heated up, it started bubbling, and instead of melting, it transformed into a opaque hard white solid. Probably if you melted sugar it would be very simillar to what I just got.

Now, just out of curiosity I put a piece of it in water, and it dissolved, actually being pretty solluble. But when I put potassium alum, it didn't dissolve at all.

Any one could answer why this happened and how I could properly melt potassium alum?


Thanks

[Arkcon]

Greetings, PwnageBR:, I'd like to welcome you and all the new students to the Chemical Forums.  But I'd like to ask you to trouble yourself to read our Forum Rules{click}. You already accepted them when you signed up for our forum, and they apply to you, whether you agree with them or not, or even if you're unaware of them.

Our rules specify that we want to see your work, and then, we want to give you hints, so that you learn for yourself.  It doesn't matter if you're a new student, or a dedicated amateur, we need to know what you know, and what you think, so we know what level you're at, so we can give useful hints, so your knowledge can grow.

So let's get started:

So I got a few small chunks of potassium alum, and wanted to melt it to make 1 big chunk

According to many websites, potassium alum melts at ≈ 92°C (200 °F).

It is also transluscent

So far, so good.  Sound like what I found on Wikipedia.

So I took a small piece of it, to test if it really worked

When I got it heated up, it started bubbling, and instead of melting, it transformed into a opaque hard white solid.

OK.  These are good observations, that match what we can read about.

Probably if you melted sugar it would be very simillar to what I just got.

Now, just out of curiosity I put a piece of it in water, and it dissolved, actually being pretty solluble. But when I put potassium alum, it didn't dissolve at all.

These observations don't match what we can read.

Any one could answer why this happened and how I could properly melt potassium alum?

Uh ... lots of random stuff here.  Hard to know where to begin.

Thanks

We're glad to help, but if you want to learn, the steps and conclusions have to be real, make sense, and follow logically.  We can't really help otherwise.

Try this link: https://en.wikipedia.org/wiki/Alum#Chemical_properties

[Intanjir]

You did in fact melt it. It would be unusual to see bubbles form inside a solid.
So for a moment at least, you had liquid.

What kind of gas was inside those bubbles?

[Borek]

You did in fact melt it. It would be unusual to see bubbles form inside a solid.
So for a moment at least, you had liquid.

What kind of gas was inside those bubbles?

Actually I am not convinced "melted" is the best word to use here. That's why it is so difficult case to analyze and explain to someone not knowing anything about hydrates.