Question 4

[drillr042980]

If we assume that sucrose breaks down into glucose and fructose, wouldn't the molality be higher in the sucrose + water beaker thus making it have a higher elevated boiling point?

I guess the question is, does sucrose dissolve in water?

[nedaa.asba6809]

Sucrose dissociates completely in water, therefore what you probably meant in your question whether it is a complete or a partial dissociation. And to answer the question of dissociation, sucrose (under standard conditions) will require a catalyst (ie enzyme) to completely dissociate.

Regarding the question, molality is the factor to be considered. Since there is greater number of moles in the case of the glucose (of course comparing between equal masses of sucrose and glucose), as a result glucose will have a higher molality and a greater boiling point.

[admin]

Bump.

[shahj21772]

I chose answer A for this question. I thought the complete equation for BP elevation was deltaTb = KBim, where i is the number of ions. I thought sucrose would create more particles (being a dissacharide) which would outweigh the effect caused by the larger molality value exhibited by the glucose. Could you please explain to me why this thought process is incorrect?

Thank you!