Question

90g of water spilled out from vessel in the room on the floor.assuming the water vapour behaving as an ideal gas,calculate the internal energy change when the spilled water undergo complete evaporation at 100c .(given the molar enthalpy of vaporisation of water at 1 bar and 373k=41kjpermole)

Answer 1

Answer: =201.8 KJ

Explanation:

△U=?

H

2

O(l)⟶H

2

O(g)

[41×10

3

J/mol]

∴ For 18g⟶41×10

3

For 90g⟶?=

18

90×41×10

3

=205 KJ/mol

△H=△U+△nRT

⇒205×10

3

=△U+1×8.314×373

⇒△U=205000−3101.12

=201.8 KJ