Question

I'm stuck on this problem. "You mix 100 ml 60 degree C water with 100ml 20 degree C water. Find the final temperature" Changing 100 ml to .1kg, I set .1*4186*(60-final temp.) + .1*4186*(final temp-20)=0 but my t's cancel out. I know it would work if I set my first half of equation to (Final temp-60) but writing it this way doesn't make sense to me since the final temp. is somewhere between 20 and 60. Please help!!

Answer 1

Your should take final-initial temperature on both sides. On left hand side, u r taking initial minus final whereas on right hand side u r taking final minus initial which is wrong