# Determine the latent heat of an unknown substance

I need to determine the latent heat of an unknown substance X in kcal/g if 3.0g of boiling liquid X are completely vaporized in 1.5 hours by an energy source of 10kcal/hr.

Thanks a million!!!!!!!!!!

Dave

berkeman
Mentor
Welcome to the PF, dhkdl1. Homework and coursework questions like this need to be posted in the appropriate forum in the Homework Help section of the PF, and not in the general technical forums. I've moved your thread to the Homework Help forums, leaving a redirect in the general technical forum.

And on questions like these, you are required to show us the relevant equations and some of your own work, in order for us to be able to provide some tutorial help to you.

So what equations do you think apply here?

still need help!!!!

I need to determine the latent heat of an unknown substance X in kcal/g if 3.0g of boiling liquid X are completely vaporized in 1.5 hours by an energy source of 10kcal/hr.

Thanks a million!!!!!!!!!!

Dave

The formula my book show for Q=cmdelta T, I guess what I reaaaallllyyy need to know is how to find deltaT given the above problem and then the Lv(latent heat of the unknown substance). This too is a distance learning experience. So please point me in the right direction