<p>small positive since T can't be negative at least on the Kelvin scale
--+-</p>
<p>I thought it could be negative on the kelvin scale. isn't absolute zero -273K?</p>
<p>Given that a solution is 5% sucrose by mass, what additional information is necessary to calculate the molarity of the solution?</p>
<p>I. The density of water
II. The dnesity of the solution
III.The molar mass of sucrose.</p>
<p>absolute zero is 0 K.</p>
<p>I think absolute zero is 0 K. -273 K means that light has frozen.</p>
<p>I, III 5g/100g 100g solution convert to volume.
then convert 5g of sucrose to moles. Moles of sucrose/ volume of water.</p>
<p>BTW, does anyone have the 1999 or 2002 AP CHEM Multiple Choice by any chance?</p>
<p>I think I have 1999. My teacher handed it out to us. My scanner unfortunately doesn't work.</p>
<p>The question is a real '94 chem question... and the answer is, unfortunately, II and III.</p>
<p>oh yeah. I thought it was density of solute. Oh how stupid of me.</p>
<p>Ask some questions from the 1999... i need it!</p>
<p>appropriate uses of a spectrophotometer?
I determining the concentration of a solution Cu(NO3)2
II measuring the conductivity of a solution of KMnO4
III determining which ions are present in a solution that may contain Na+, Mg2+, Al3+</p>
<p>Temperature must be low in order for the reaction to be spontaneous (Delta G is negative)</p>
<p>Equation used:
G = H - TS (missing deltas)</p>
<p>Le Chatelier's law states that when temperature is increased the reaction will proceed in the _____________ direction.</p>
<p>well it depends if the reaction is exo or endo
exo: left
endo: right</p>
<p>imiracle: Guessing I and II</p>
<p>Meng: Reverse (left) (? not sure on this one)</p>
<p>I believe endothermic (let me look this one up) since the reaction must absorb the heat to compensate for temperature change (equilibrium)</p>
<p>Yep. Endothermic.</p>
<p>First and second laws of thermodynamics...?</p>
<p>I only
spectro whatever is used according to beer's law
Absorbance=e(weird one, some coefficient)C(concentration)l(path length, distance from the beam)
so concentration is proportional to absorbance. So using the molarity with l absorbance can be calculated which is the usuage of a spectro whatever.</p>
<p>for endo if the temperature increases the reaction wants to use up the excess energy shifting to the right. opposite for exo.</p>
<p>1st: energy of the universe is constant
2nd: if a process is spontaneous in one direction, it cannot be in the reverse direction.</p>
<p>Damn.. initally put I only then edited it. lol</p>
<p>well it doesn't apply to equalibrium reactions in which the reaction goes back and forth. If the process is spontaneous in one direction it means that the reverse reaction does occur but at a negligible amount. It's like you disregard the reverse reaction for H+ + OH- _> H2O because it scarcely occurs.</p>