Apatient arrives in the emergency with a burn caused by steam. calculate the heat that released when 17.7 g of steam

The steam releases 39.9 kJ when it condenses..

The steam condenses and transfers its energy to the skin.

q = mΔH_cond = 17.7 g × (-2257 J/1 g) = -39 900 kJ = -39.9 kJ

The negative sign shows that the steam is releasing energy

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%