General chemistry question from chads videos

[adamrose]

"higher Intermolecular forces lead to higher bp, mp,"- from one of the first lessons

"freezing point depression: solute is added which raises the Intermolecular forces" - solubility lesson
so does freezing point (which is the same as melting point?) go higher or lower when solute is added?

thank you

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[DustFreeEraser]

Solute wouldn't "raise" the IMF per se, it would disrupt it, lowering the bp/mp

 

[100%permwinner]

The freezing point decreases in the presence of solute. The most common example is when salt is added to water. In pure water, water molecules form perfect hexagonal crystal. When salt ions are introduced, the formation of perfect crystal is disrupted. The new solution takes a longer time to freeze.
Review: ΔTf = ikfm where i = moles of ions, kf = freezing point depression constant (1.86 for water), and m is the molality of the solution (mol of solute/kg solvent)
Freezing point of water + solute = freezing point of pure water - ΔTf

 

[100%permwinner]

Solute wouldn't "raise" the IMF per se, it would disrupt it, lowering the bp/mp

Agree that present of solute lowers the melting point. The presence of solute actually increases the boiling point. The solute particles become a barrier that the solvent molecules must have greater energy to overcome.
This video should be valuable.

 

[DustFreeEraser]

Err yes, I meant increase bp, decreases mp

Actually I'm lost

 

[whitepapertree]

Err yes, I meant increase bp, decreases mp

Actually I'm lost

The solute decreases the vapor pressure of the solvent (higher BP) and disrupts the ability to form crystals which requires a lower melting point (needs it to be colder in order to freeze)

 

[adamrose]

The solute decreases the vapor pressure of the solvent (higher BP) and disrupts the ability to form crystals which requires a lower melting point (needs it to be colder in order to freeze)

10/10 concise answer