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votes
2answers
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Safe endothermic reaction that gets below freezing?

I have a project/idea I am working on but I am only 14 years old and I need some help. I'm looking for an endothermic reaction that gets below freezing, but the chemicals before the reaction and ...
5
votes
4answers
14k views

How do I control the negative temperature in an experiment?

If one were to adjust the positive temperature in an experiment, they would use a heating plate, or a stovetop. How would one adjust negative temperatures in an experiment? (Not keeping the ...
3
votes
1answer
559 views

50-90'C color changing chemical to use as warning marker for hot electronics?

I am testing electronics with many potentially unstable contacts, and I wish to monitor if they rise above 50 to 90 degrees Celsius, i.e. using carbon paper that would darken progressively from 50 to ...
4
votes
1answer
993 views

Determining which hydrate of calcium chloride I have?

I have calcium chloride in the form of small (1-2 mm) round white pellets, originally bought at a home-brew shop. The packaging gives no indication what hydrate it is. Since each water molecule adds ~...