Australia's Science Forum

Can anyone tell me what reaction (endo or exothermic) is adding water to plaster of Paris? Our yr11Chem students did it and teacher asked ME, what kind of reaction it is.

Lada

tell the teacher you could tell them for a consultation fee....

Hi, exothermic gives off heat,endothermic cools.Thet person is teaching Science????!!!!!

Yes, I know which is which, but just the one with plaster of Paris is puzzling us.
Lada

measure the temperature of the water, then add the plaster of paris, stir, measure temp again and you will have your answer. Just be sure to remove the thermometer before it sets! Perhaps it is heat-neutral (if there is such a thing!). I don't know that all chemical reactions have a change in heat.

The reaction of POP with water is normally exothermic ie it gives off heat.

Yeah it is exothermic. I remember the moulds getting warm in my hands when making them for my kids, years ago.

It has to be used carefully as it can cause burns. Google "plaster of paris burns" for some scary stories.

Plaster of Paris is exothermic.. and take care - students have had burns from making face masks with it...