5 gram of water at 30 celsius is heated until it melts and vaporizes into steam at 115 celsius. How many calo

Answer 1

water melts?! anyways :

5 grams water ( 30 c) ------> 5 grams water (100 c)------->5 grams vapor (100 c) ------> 5 grams vapor (115 c)


( 5 x 1 x 70) + ( 5 x 540 ) + ( 5 x 0.5 x 15) = 3087.5 cal


what you needed to know: C water=1 cal/gr.k

C vapor = 0.5 cal/gr.k

Lv water =540 cal/gr.k

and of course: Q=mc(T2-T1) & Q=mLv

good luck

Answer 2

From 30C -> 100C:
H = 5 * (100-30) = 350 cal

Vaporization (given the latent heat of vaporization of water is 540 cal/g):
H = 5 * 540 = 2700 cal

Total: 350 + 2700 = 2850 cal