you take 295.5 g of a solid at 30.0 c and let it melt in 425 g of water. the water temperature decreases from 85.1 c to 30.0 c. calculate the heat of fusion of this solid

Explanation:

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In this case, since the heat of fusion of a solid substance stands for the energy required to melt it, which is a phase transition from solid to liquid, we can see that the heat lost by water is that gained by the solid, so we can write:

Thus, by using the water data and its specific heat (4.184), we obtain:

Next, since the heat of fusion of a substance is usually represented in terms of energy per amount of substance, we use the mass of solid to obtain:

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atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8