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Consider two flasks that contain different pure substance at 20 degree C. The su

ID: 979382 • Letter: C

Question

Consider two flasks that contain different pure substance at 20 degree C. The substance in one flask (substance A) has a molar mass of 100g/mol and can form hydrogen bonds between molecules. The other substance (B) has a molar mass of 105 g/mol and has dipole-dipole IMF. Assuming that both molecular structures are similar (no significant difference in surface area), which flask contains substance A? Explain. If the temperature of each flask is increased by 15 degree C, how would the pictures change (assuming you stay below the boiling points of both)?

Explanation / Answer

a) due to presence of hydrogen bonds in substance A . the attractions

between the molecules is more.so that, No of gas molecules in vapour state is less.
therefore, the flask with less no of molecules in vapour state is having substance A.

b) if the temperature increases,the vapour pressure increases,that results more no of gas molecules

in vapour state.