June 2010: Chemistry

<p>ok lets say you burn it. hows that going to help you titrate it?</p>

<p>oh shoot you might be right with the analytical balance think because it measures mass, i don’t think mass is necessary for a titration</p>

<p>but at the same time, I’ve never heard of burning a solid for a titration</p>

<p>Yea but it’s like evaporation. You have to evaporate all the water for the thing to be Solid, so you use the bunsen burner for that.</p>

<p>wait for the titration question, it said a solid mixture of NaCl and NaOH? </p>

<p>i thought the NaCl was a buffer for the HCl, was HCl stated as a liquid?</p>

<p>Uh NaCl is a salt, HCl is a strong acid, its conjugated base is weak so its not a buffer. And yea the problem said SOLID; I’m pretty sure.</p>

<p>I think HCl was just stated as an acid</p>

<p>wait sike nvm yeah buffers = weak acids/bases and their conjugate bases/acids </p>

<p>i’m still convinced it’s a bunsen burner though</p>

<p>Umm it said “a mixture of solid NaOH and NaCl.” I checked it like three times to make sure cuz I was confused. =.=</p>

<p>Was the molarity of HCl known? Was it the titrant?</p>

<p>I’m not sure the molarity was given, but the base was the thing in the buret-that’s standard titration setup.</p>

<p>Oh dammit yeah it was balance, because knowing the mass of a mixture doesn’t do you any good does it? Wow I feel like crying…</p>

<p>2 omits + who knows how many wrong</p>

<p>If HCl was the titrant, and it wasn’t stated whether it was solid or solution, then a balance would help determine the # of moles and thus the molarity of Hcl</p>

<p>and wouldn’t bunsen burner be a little dangerous? use a hot plate!</p>

<p>for the mendeleev thing i put FF because it said physical properties.but u can only like determine chemical property through periodic table thing right??..and for the Temeprature will increase the rate to reach equilibrium…is that true??..because i was kind of thinking when u increase the temperature…u change the equilibrium constant too…so…</p>

<p>^^^yeah i just realized that </p>

<p>you’re not given the specified molarity so you’ll have to make the base solution yourself to determine the M of the HCl by measuring the amount of solid NaOH and NaCl on an analytical balance and then making a solution</p>

<p>Oh well, since everyone says its bunsen burner, I’m probably wrong. :(</p>

<p>IAmCool-</p>

<p>That’s my thinking also. You do not need a bunsen burner to heat up the NaOH pellets to dissolve in the water. It will dissolve by itself to form a basic solution.</p>

<p>Can someone explain to me the T/F question about evaporation/lowering temperature/increasing entropy?</p>

<p>H20 (liquid) -> H2 (gas) + 02 (gas)
This is an endothermic process (you need to put in energy to make this process work), and entropy increases (liquid to gas). So just TT.</p>

<p>Here’s one I remember: Low temperature and high pressure = deviation from ideal gas</p>

<p>u guys remember the 4L Hydrogen and 3 L Oxygen? was it just 1L oxygen remaining?</p>