<p>Hey guys!
Good to know everyone did well! =D
I guess Chemistry was my best subject, so I’m just cheering for an 800!
The unsafe lab procedure… I put rinsing the buret with the titrant solution (why would anyone do that? seemed pretty illogical to me haahha)
And the element that couldn’t be found in its elemental state was sodium… Just had a lab class yesterday about alkali metals and electrodeposition… hehehe lucky me!</p>
<p>@brazbloke
dude it is right to rinse buret with titrant solution. Because there might be air bubbles in the edge of the buret, you want to make sure that 100% of the stuff in the buret is the titrant solution.
I put the 4th one i dont 100% remember</p>
<p>@brazbloke
Mulgrave is right, actually you want to rinse with the titrant not water because it might throw off the calculations because water is neutral. I read it in the Barron’s I think?
The correct one, I think, is using a graduated cylinder and a bunsen burner with the hood or something like that.</p>
<p>@brazbloke, I also put the fourth one like mulgrave, but can’t remember what the answer was, just that it would melt haha.</p>
<p>Na will not exist in nature in its elemental form because it’s highly reactive. Exposing it to the water vapors in the atmosphere can be enough to make it react with water. </p>
<p>You have to rinse the burette with the titrant not water because water can affect the pH of the titrant when it’s added into the burette.</p>
<p>ahh it is so nerve-wracking reading all of this. what was the question about diamond and graphite? i forget what it was but i know i wasnt sure about it.</p>
<p>oh and also can H2O act as a very weak acid?</p>
<p>Diamond and Graphite are both allotropes (same element different structures) of Carbon (C). </p>
<p>The H2O part I’m not that sure… what was the question? I remember an answer choice that sounded better than H2O… I believe CO2.</p>
<p>The H2O question asked which of the statements were false. It said like, “it’s denser at 4C than at 0C”, “it can act as a very weak acid,” and some other stuff that was obviously true. I said the weak acid one.</p>
<p>Ohhh now I remember. It asked for which of the statements was true.</p>
<p>I believe it’s the one with 4C and 0C water.
Water at 4C IS denser than water at 0C…
4C water is a liquid, where 0C is a solid (and partial liquid too).
For water, because of its special property, 0C water (Ice) is less dense than 4C water (Liquid Water).</p>
<p>Edit- Now I’m confused… it asked for the false one? I thought it asked for true… I might have gotten that wrong for not reading the question properly… </p>
<p>BTW Water CAN act as a weak acid*</p>
<p>Edit2- Maybe the questino asked which of the statement is false, and said that water at 0C is denser than one at 4C. That’s what I think I saw.</p>
<p>Oh maybe 
that would make sense. Another question. The one where it said the temperature was like 200 K and the pressure was 1.50 and then everything was halved, the volume stayed the same (8 L) right?</p>
<p>Temperature / Pressure Directly/Indirectly affect volume.
If temperature is doubled then pressured halved, it’s essentially</p>
<p>Volume x 2 / 2</p>
<p>so it would go back to the original volume, so yes.</p>
<p>Thanks! By the way, I was looking at another discussion of this test and everyone’s saying that the one about water and the false statement was that it’s a strong electrolyte. Got that wrong…oops.</p>
<p>OHHH yes NOW I remember. Thanks for telling me.</p>
<p>That was the answer I put, since water is NOT an electrolyte in its purest form (only when it has dissolved ions in it)</p>
<p>I originally chose the 0C 4C one then I got out of the trap after re-reading the question… then I was able to choose the correct one. Whew!</p>
<p>what was the answer to the question about the pH of HCl
It was like .01M or .001M concentration of HCl has a pH of
a)-.01
b)2
c)13
d)?
e)?
anyone remember this, what was the answer?</p>
<p>@bren216</p>
<p>pH= -log[H+]
pH= -log[0.01]</p>
<p>Therefore, the pH of HCl is 2.</p>