A sample of 0.1 g of water at 100^@ C and normal pressure (1.013 xx 10^5 Nm^(-2)) requires 54 cal of heat energy to convert to steam at 100^@ C. If the volume of the steam produced is 167.1 cc, the change in internal energy of the sample is ____

A sample of 0.1 g of water at 100^@ C and normal pressure (1.013 xx 10

1.	A sample of 0.1 g of water at 100^@ C and normal pressure (1.013 xx 10^5 Nm^(-2)) requires 54 cal of heat energy to convert to steam at 100^@ C. If the volume of the steam produced is 167.1 cc, the change in internal energy of the sample is ____
Answer» <P>84.5 J 104.3 J 42.2 J 208.7 J Solution :`DeltaQ`=54 cal = `54xx4.18`J =225.72 J …(1) `DeltaW=PDeltaV` `=P(V_2-V_1)` `V_2`=volume of steam `V_1`=volume of water `=1.013xx10^5[167.1xx10^(-6)- 0.1xx10^(-6)]` [`because` 1CC=`10^(-6) m^3`] `=1.013xx10^5xx167xx10^(-6)` `DeltaW` = 16.917 ..(2) Now `DeltaU=DeltaQ-DeltaW` =225.72 - 16.917 [`because` From equ. (1) and (2)] =208.8 J `therefore DeltaU` = 208.7 J nearest value