18-0 g of water completely vapourises at 100 deg-C and 1 bar pressure and the enthalpy change in the process is 40-79 kJ mol ndash-1- What will be the enthalpy change for vapourising two moles of water under the same conditions- What is the standard enthalphy of vapourisation for water-

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Byju's Answer

Standard XII

Biology

Osmotic Pressure and Osmotic Potential

18.0 g of wat...

Question

18.0 g of water completely vapourises at 100°C and 1 bar pressure and the enthalpy change in the process is 40.79 kJ mol –1. What will be the enthalpy change for vapourising two moles of water under the same conditions? What is the standard enthalphy of vapourisation for water?

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Solution

$N o o f m o l e = \frac{G i v e n m a s s i n g}{M o l a r m a s s} = \frac{18}{18} = 1 m o l e F o r 1 m o l e o f w a t e r t h e e n t h a l p y c h a n g e f o r t h e v a p o u r i s a t i o n = 40.79 k J / m o l F o r t w o m o l e s o f w a t e r t h e e n t h a l p y c h a n g e f o r t h e v a p o u r i s a t i o n = 2 \times 40.79 = 81.58 k J S \tan d a r d e n t h a l p y o f v a p o u r i s a t i o n ∆ H_{f}^{0} = 40.79 k J / m o l I t s s a m e a s t h e g i v e n v a l u e . B e c a u s e t h e g i v e n c o n d i t i o n i s t h e s \tan d a r d c o n d i t i o n - 1 b a r$

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Similar questions

18.0 g of water completely vaporises at $100^{\circ} C$ and 1 bar pressure and the enthalpy change in the process is 40.79 kJ $m o l^{- 1}$ . What will be the enthalpy change for vaporising two moles of water under the same conditions? What is the standard enthalpy of vaporisation for water?

Q. Standard enthalpy of vapourisation

Δ_{v a p} H^{0}

for water at

100^{0} C

40.66 k J . m o l^{- 1}

. The internal energy change of vapourisation of water at

100^{0} C

(i n k J . m o l^{- 1})

is:

Assuming that water vapour is an ideal gas, the internal energy change $(Δ U)$ when 1 mol of water is vapourised at 1 bar pressure and 100 $^{0}$ C will be:

[Given molar enthalpy of vapourisation of water at 1bar and 373 K=41 kJ mol $^{- 1}$ ]

Q. Standard enthalpy of vapourisation