How much heat is absorbed by 15.5g of steam to turn into liquid water when its temperature is decreased from 120.0°c to 100.0°c?

- 618.8 J.

Explanation:

Q = m.c.ΔT,

where, Q is the amount of heat released by steam (Q = ??? J).

m is the mass of the steam (m = 15.5 g).

c is the specific heat of the steam (c of steam = 1.996 J/g.°C).

ΔT is the difference between the initial and final temperature (ΔT = final T - initial T = 100.0°C - 120.0°C = - 20.0°C).

∴ Q = m.c.ΔT = (15.5 g)(1.996 J/g.°C)(- 20.0°C) = - 618.8 J.

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation: