Question

when some amount of copper at 60 degrees centigrade is added to 1 litre water at room temperature(27 degrees centigrade)the resultant temperature is found to be 40 degrees centigrade.the amount of copper used is.....

Answer 1

     Mixtures:

Let the amount of copper be M1 grams.         Temperature T1 = 60°C
amount of Water M2 = 1 litre = 1000 grams        temperature T2 = 27°C

Resultant temperature of the mixture = T = 40°C
$T = \frac{M1 T1 + M2 T2 }{M1 + M2}\\\\.\ \ 40 =\frac{M1*60+1000*27}{M1+1000}\\\\40\ M1+40,000=60\ M1+27,000\\\\M1=650\ gms=0.65\ kg$